On the Importance of Relationship Quality: The Impact of Ambivalence in Friendshipson Cardiovascular Functioning

Julianne Holt-Lunstad, Ph.D.Brigham Young University

Bert N. Uchino, Ph.D., Timothy W. Smith, Ph.D., and Angela Hicks, Ph.D.University of Utah

ABSTRACT

Background: Social relationships are reliably related torates of morbidity and mortality. One pathway by whichsocial relationships may influence health is via the impactof relationship quality on cardiovascular reactivity duringsocial interactions. Purpose and Method: This study exam-ined the effects of the quality of a friendship on cardiovascu-lar reactivity when speaking about positive or negative lifeevents with an ambivalent or supportive friend. To examinethis, 107 healthy male and female adults (and their same-sex friend) were recruited. Results: Results revealed thatparticipants exhibited the greatest levels of systolic bloodpressure reactivity when discussing a negative event with anambivalent friend compared to a supportive friend. We alsofound higher resting levels of heart rate and lower respiratorysinus arrhythmia among those who brought in ambivalentfriends than those who brought in supportive friends.Conclusion: Individuals may not be able to fully relax inthe presence of ambivalent friends and may not benefit fromsupport during stress. This research may help clarify thehealth-related consequences of differing types of socialrelationships.

(Ann Behav Med 2007, 33(3):278–290)

INTRODUCTION

Social relationships play a central role in our everydaylives, and evidence suggests that these relationships influ-ence physical health (1,2). Social support is inverselyrelated to the prevalence and incidence of several diseases;the most common being coronary heart disease (CHD)(3–5). These findings are often taken as evidence for thehealth benefits of social relationships, however, even closerelationships are not entirely positive (6). Although socialrelationships can be sources of warmth, caring, nurturance,and understanding, they can also be sources of conflict,criticism, jealousy, and rejection (7). Research from theTerman Life Cycle study suggests that past negativity insocial relationships predicts earlier mortality (8,9).

Therefore, a more complete understanding of the health-related consequences of social relationships requires con-sideration of both their positive and negative aspects. Ofimportance, positivity and negativity are separable dimen-sions (10–13), and many individuals construe their relation-ships as having a mix of positive and negative feelings (e.g.,an overbearing mother, competitive friend, volatileromance [14]). As noted by others, the implications ofthis ‘‘ambivalence’’ within relationships have not beenadequately considered in social support theory or research(7,14,15).

Given that ambivalent relationships are characterizedby a mix of both positive and negative feelings, it is unclearwhat the implications of these relationships may be for ourhealth. Can individuals benefit from the positivity associa-ted with ambivalent relationships or is negativity more sali-ent, leading to harmful effects? Although more research isneeded, our prior findings suggest that ambivalent relation-ships are distinct from supportive (i.e., primarily positive),indifferent (i.e., not particularly positive or negative), andaversive (i.e., primarily upsetting) relationships and maybe related to detrimental outcomes (16). For example,older adults with higher numbers of ambivalent relation-ships within their network had higher levels of depressivesymptoms and greater cardiovascular reactivity (CVR)during stress (14). In addition, ambulatory systolic bloodpressure (SBP) was highest when participants were inter-acting with individuals they rated as normally feelingambivalent toward compared to those toward whom theyfelt primarily positive, indifferent, and primarily negative(17). Thus, individuals may not be able to benefit fromthe positivity associated with ambivalent relationshipsand such ambivalence may be more detrimental than sim-ple negativity.

Prior research indicates that ambivalent relationshipsmay be health relevant; however, they have failed to eluci-date the context in which ambivalent ties may be harmful.For instance, although the ambulatory blood pressurestudy (17) did assess the quality of the interaction, infor-mation on the exact nature of the interaction (e.g., whetherthey were actually seeking support or simply having a cas-ual conversation) was not obtained. In our prior work wehave found that individuals did not benefit from supportreceived from an ambivalent friend compared to a support-ive friend (18). However, this study did not include otherinteraction contexts (e.g., discussion of positive events) as

Reprint Address: J. Holt-Lunstad, Ph.D., Department of Psy-chology, Brigham Young University, 1024 SWKT, Provo, UT84602. E-mail: julianne.holt-lunstad@byu.edu

# 2007 by The Society of Behavioral Medicine.

278

comparisons. Participants in this study were also not ran-domly assigned to relationship conditions, hence makingthis study open to alternative explanations (e.g., due toexisting personality differences). Thus, we need to betterunderstand the context that may explain how such relation-ships impact health.

Two potential broad mechanisms could underlie theassociations between ambivalent relationships and detri-mental cardiovascular outcomes. First, interactions withambivalent ties may entail significant interpersonal stress(i.e., stress enhancing hypothesis). If a social network mem-ber is primarily a source of negativity, one may habituate tothe aversive relationship by using specific coping strategies(e.g., discounting or simply avoiding these people). How-ever, an ambivalent network member (someone you feelparticularly positive and negative toward) may be less pre-dictable, less easily discounted or avoided, and thus maybe associated with heightened interpersonal stress (14,19).Thus, individuals may not be able to relax when in the pres-ence of or while interacting with ambivalent network ties. Asecond pathway involves interference with social support(i.e., support interference hypothesis). Social relationshipsthat are supportive are thought to have an effect on healthby buffering the negative effects of stress. However, despitethe positivity that exists in ambivalent relationships indivi-duals may not be able to benefit from support from such ties,because the coexisting negativity may lead them to eitheravoid disclosure or question the intent, sincerity, or possiblesubsequent consequences of support (20). Although thestress-enhancing and support interference hypotheses rep-resent distinct pathways by which ambivalence may influ-ence health, they are not necessarily competing hypothesesas both may potentially be operating (e.g., it is possible thatstress may be operating to interfere with support).

We tested these hypotheses by examining the impact ofambivalent relationships on CVR in a controlledexperimental design. Exaggerated CVR to stressful situationsmay influence the development and=or expression of CHD(for reviews, see 21,22). We randomly assigned participantsto discuss positive, negative, and neutral life events with anambivalent or supportive friend. If ambivalent relationshipsare general sources of stress (i.e., stress-enhancing hypoth-esis), we would expect increased reactivity when individualsare discussing both positive and negative events with anambivalent friend as compared to a supportive friend. How-ever, if individuals simply do not benefit from support duringtimes of stress (i.e., support interference hypothesis), then weshould see increased reactivity primarily when participantsdisclose negative events to an ambivalent friend.

METHOD

Design

Three between-participants factors were included:relationship quality (supportive, ambivalent), event (positive,

negative), and participant gender (male, female). The depen-dent variables were residualized change scores for physiologi-cal measurements and several self-report measures.Participants were randomly assigned to the conditions ofrelationship quality and event discussion. Relationship typeand partner gender was held constant, with all participantsrequired to bring a same-sex friend.

Participants

Participants were recruited from introductory psy-chology courses at the University of Utah, received extracourse credit, and included 56 women and 51 men(N ¼ 107). The participant’s friend received $15 compen-sation. Consistent with prior research (e.g., 23), the follow-ing self-reported inclusion criteria were used to selecthealthy participants: no hypertension, no cardiovascularprescription medication, no history of chronic disease witha cardiovascular component (e.g., diabetes), no recent his-tory of psychological disorder (e.g., major depressive dis-order), no tobacco use, and no consumption of morethan 10 alcoholic beverages per week.

Procedure

Testing was divided into two sessions. In the first, part-icipants were asked to complete the Social RelationshipsIndex SRI (detailed next) in which they rated their socialnetwork. We then asked the participants to contact andbring in a specific friend from their list of rated relation-ships. This individual was selected by the experimenterbased on each participant’s random assignment to relation-ship (supportive or ambivalent) condition.1 Participantswere unaware of the relationship condition. Approximately2 weeks later, participants brought their friend to the lab-oratory (see Table 1 for summary of procedures and mea-sures). Upon arrival both individuals completed aninformed consent document and a demographic question-naire. Participants’ self-reports of health were checked forreliability against the inclusion criteria. Participants andtheir friend were told that because cardiovascular function-ing can differ according to whether one is speaking or not,we needed to be certain that participant was speaking dur-ing certain portions of the experiment. The friends weretold that part of their responsibility during the experimentwas to keep their friend talking. The friend was told,‘‘Sometimes the best way to do this is to be supportiveand sometimes it is to stir things up a bit; however, allwe ask is that you say what would come natural to youin the situation.’’

Participants were then escorted by themselves to aseparate sound-attenuated room where four mylar bands

1 Two individuals did not have both ambivalent and support-ive relationships listed on their SRI. When dropping these indivi-duals from our analyses the results remain consistent; therefore,results reported include these participants’ data.

Volume 33, Number 3, 2007 Relationship Quality and Cardiovascular Function 279

were placed in the tetrapolar configuration for impedancecardiograph recordings according to published guidelines(24). An occluding cuff was placed on the left arm. Theywere seated in a comfortable chair and asked to completequestionnaires (see measures). Following this adaptationperiod of approximately 20 min, the friend was escortedinto the room and seated next to the participant. The par-ticipant and friend were instructed to relax for the next12 min while resting measures of cardiovascular functionwere obtained. Both were told not to talk during the restperiod, and a curtain was drawn between them. As a neu-tral comparison to the event discussion, the participant andfriend were instructed to discuss with each other for 4 minwhat they do during a normal weekday, alternating speak-ing and listening for 1-min epochs to hold constant speecheffects on CVR (e.g., 25).

Before the event task began, a second baseline was alsoobtained. The procedures were identical to the first withthe exception that it was 7 min in length. Participants werethen asked to list up to five past experiences that wereparticularly negative=positive (depending on randomassignment) that they felt comfortable discussing with theirfriend as part of our experiment. These were rated on ascale of 1 to 5 on degree of importance, positivity, andnegativity, in comparison to all possible negative=positiveevents in their life. The experimenter selected a situation=event that was rated as moderately high such that all dis-cussions, regardless of condition, would be relativelyequivalent on these aspects to control for intensity. Exam-ples of negative events discussed included almost getting ina car accident, making a commitment but then didn’t fol-low through, meeting girlfriend’s family, boyfriend stillmaintains friendship with ex-girlfriend, getting fired frompart-time job, and finals. Examples of positive eventsdiscussed included boyfriend flying in from out of townfor surprise visit, spending the day with Mom, getting

a promotion at work, and making the dance team. Theparticipant and friend discussed the event for a total of6 min. Participants were asked to discuss three aspects ofthe selected situation=event: first to describe in detail theexperience=event, second to talk about his or her thoughtsand feelings regarding this situation=event, and finally todiscuss how they handled the situation=event and=or howthey might have changed anything. After each aspect, thefriend was given 1 min to respond. Thus, again they alter-nated speaking and listening for 1-min epochs to holdconstant speech effects on CVR.

Cardiovascular assessments were taken during each dis-cussion task and the last 5 min of each baseline. Heart rate(HR), impedance-derived measures, and respiratory sinusarrhythmia (RSA) were obtained continuously, while systolicblood pressure (SBP) and diastolic blood pressure (DBP) wereobtained once every 90 sec during baseline and at the begin-ning of each minute during the discussion tasks. Self-reportedstate anxiety was assessed before and after each discussiontask. Perceptions of the friend during each of the discussionswere rated using the Impact Message Inventory (IMI; seedescription next) and completed immediately following eachdiscussion. At the completion of the valenced discussion part-icipants completed a rating of their thoughts and feelingsregarding the discussion as a manipulation check.

Measures

Self-Report Measures

Social relationships index (SRI). The SRI was deve-loped as a self-report version of the social support inter-view (26,27). Participants rated up to 10 friends in termsof how helpful and upsetting they were from 1 to 6(extremely), and on length of time known, amount of con-tact per week, importance, predictability, and how likelythey are to go to this person for support. In our prior work,

TABLE 1

Physiological and Psychological Dependent Measures Taken During Each Experimental Epoch

Experimental Epoch Length of Epoch Measurement(s)

Prescreening SRI: rating up to 10 friendsPrebaseline 1 Consent forms, background and health questionnaires, ratings of friend (e.g.,

SRI, QRI)Baseline 1 12 min SBP, DBP, HR, RSA, PEP, TPR, COPostbaseline1 State anxiety,Neutral discussion 4 min SBP, DBP, HR, RSA, PEP, TPR, COPostneutral Discussion State anxiety, IMIBaseline 2 7 min SBP, DBP, HR, RSA, PEP, TPR, COPostbaseline 2 State anxietyPrep for Discussion 2 Experience ratingDiscussion 2 6 min SBP, DBP, HR, RSA, PEP, TPR, COPostdiscussion 2 State anxiety, IMI, Postdiscussion Rating, and thought listing

Note. SRI ¼ social relationships index; QRI ¼ quality of relationships index; SBP ¼ systolic blood pressure; DBP ¼ diastolic blood pressure;HR ¼ heart rate; RSA ¼ respiratory sinus arrhythmia; PEP ¼ pre-ejection period; TPR ¼ total peripheral resistance; CO ¼ cardiac output;IMI ¼ impact message inventory.

280 Holt-Lunstad et al. Annals of Behavioral Medicine

these measures of positivity and negativity were temporallystable with significant 2-week test–retest correlations(r ¼ .81, p < .001 for positivity; r ¼ .83, p < .001 fornegativity) (14). Scores were used to determine the relation-ship qualities (i.e., supportive, ambivalent, aversive, indif-ferent) in the participant’s social network. We selected afriend who was rated as either supportive or ambivalent(depending on random assignment) for them to bring tothe laboratory. Although our model also includes relation-ships that would be classified as aversive (high negativity,low positivity) and indifferent (low positivity, low nega-tivity), it would have been unfeasible and unlikely that wecould get participants to bring such relationships in withthem to the lab, so we focused primarily on friendships.Friends were rated in terms of three different contexts: (a)when they need support such as advice, understanding, ora favor; (b) when they are excited, happy, or proud of some-thing; and (c) during routine daily interactions, conver-sations, or activities. The individual selected to come inwith the participant was the individual listed who mosthighly characterizes the assigned condition (i.e., supportiveor ambivalent) across all three contexts. Consistent with ourprior work, the criterion used for the classification ofsupportive was a rating of a 3 or greater on measures ofpositivity and a rating of 1 (not at all) on negativity. Forthe classification of ambivalent, a rating of a 3 or greateron the measures of positivity and a rating of greater than1 on negativity were required.

Quality of relationships index (QRI). The QRI (28)assesses supportive and conflictual aspects of relationshipsand was used as an independent check on the SRI-basedrelationship classification. This 29-item inventory includes

three scales that assess perceptions of social support,conflict, and depth in a specific relationship. The internalreliability was found to be high (.85, .91, and .84, respect-ively) for ratings of friends (28).

IMI, form II. The IMI (29) is a circumplex-basedinventory designed to assess perceptions of another’sinterpersonal behavior, along the dimensions of friendlinessversus hostility and dominance versus submissiveness. Itcontains 32-items with 4 items per octant. Kiesler andcolleagues (30) provided evidence supporting the circumplexstructure of the IMI and demonstrated its adequatepsychometric properties. It has been found to be sensitiveto similar interpersonal manipulations in prior research (31).

State anxiety scale. A short form of the SpielbergerState-Trait Anxiety Scale was administered to participantsprior to and following each discussion (32). This measurewas used as a manipulation check of the stressfulness ofdiscussing a negative versus a positive event=situation. Priorwork has found the internal consistency of the scale to behigh (Cronbach’s a ¼ .78–.80).

Additional manipulation checks. To ensure thatmanipulations were having their intended effect, a shortquestionnaire was devised that we refer to as the Post-Discussion rating (see Table 2 for list of items).Participants were asked to rate their current feelings on a6-point scale from 1 (not at all) to 6 (extremely). For

TABLE 2

Mean Post Discussion Ratings as a Function of Relationship Quality

Postdiscussion Ratings Supportive Ambivalent

1. How open were you to disclosing this event with your friend? 5.39 (0.86) 5.33 (0.89)2. How comfortable did you feel discussing this event with your friend?�� 5.44 (0.72) 4.96 (1.13)3. How helpful was your friend during the discussion?�� 4.59 (1.14) 3.98 (1.41)4. How challenging was the event discussion task? 2.81 (1.47) 2.83 (1.40)5. How upsetting was your friend during the discussion?�� 1.19 (0.39) 1.54 (0.88)6. How mixed and conflicted were your thoughts and feelings toward your friend during the discussion?�� 1.30 (0.60) 1.65 (0.78)7. How effortful was it to do the discussion task? 2.70 (1.34) 2.63 (1.26)8. How threatening was the event discussion task? 1.43 (0.86) 1.65 (0.91)9. How difficult did you find the discussion task? 2.11 (1.19) 2.24 (1.33)

10. How natural was this discussion compared to normal discussions with this friend?� 3.52 (1.38) 2.91 (1.42)11. To what extent did your friend respond as normally as he or she would outside this experiment? 4.24 (1.32) 3.85 (1.41)12. How familiar was your friend with the event that you discussed?y 3.56 (1.89) 4.15 (1.64)13. When discussing this event with this person in the past, how helpful has your friend been?� 4.63 (1.31) 4.06 (1.50)14. When discussing this event with this person in the past, how upsetting has your friend been?�� 1.20 (0.53) 1.62 (0.93)15. To what extent have you discussed this event with this friend before? 2.41 (1.11) 2.61 (1.12)16. To what extent have you discussed this event with anyone before? 2.69 (1.10) 2.78 (0.90)

Note. Values are mean (standard deviation).yp < .10. �p < .05. ��p < .01. ���p < .001.

Volume 33, Number 3, 2007 Relationship Quality and Cardiovascular Function 281

Items 15 and 16, the scale was from 1 (never) to 6 (at greatlengths).

Cardiovascular Measures

Blood pressure. A Dinamap Model 8100 monitor(Critikon Corporation, Tampa, FL) was used to measureSBP and DBP. The Dinamap uses the oscillometricmethod to estimate blood pressure. Blood pressureassessments were obtained via a properly sized occludingcuff positioned on the upper left arm of the participantaccording to the manufacturer’s specifications. Mean SBPand DBP for each epoch were averaged across minutes toincrease the reliability of these assessments.

Impedance-derived measures. A Minnesota ImpedanceCardiograph Model 304B was used to measure theelectrocardiogram, basal thoracic impedance, and thefirst derivative of the impedance signal (dZ=dt). Cardiacoutput (CO), total peripheral resistance (TPR), and pre-ejection period (PEP) were derived according topublished guidelines (33). For a more detailed descriptionof these measures and methodology see Uchino et al. (34).

RSA. RSA provides a noninvasive measure ofparasympathetic control of the heart and can varyaccording to age and posture2 (see 35). RSA wascalculated based on the digitized interbeat intervals thatwere checked and edited for artifacts using the detectionalgorithm of Berntson and colleagues (35). After lineardetrending, the heart period time series was band passfiltered from .12 to .40 Hz using an interpolated finiteimpulse response filter (36). RSA was then calculated asthe natural log of the area under the heart periodspectrum (calculated by a Fast Fourier Transform andscaled to msec2=Hz). RSA was calculated on a minute-by-minute basis and aggregated across minutes withineach epoch to increase reliability.

RESULTS

Manipulation Checks and Self-Report Measures

Relationship Classification and Correlates

To verify the classification of relationship types, weexamined its stability across sessions. The ratings of posi-tivity and negativity taken together indicate that our classi-fication criteria were met in most cases, and the overall

classification remained relatively stable.3 The test–retestcorrelations for ratings of positivity and negativity are r¼ .60 (p < .0001) and r ¼ .72 (p < .0001), respectively.

In a second set of analyses we examined the associationbetween our initial social relationship classification withthe independent measure of social relationships (i.e.,QRI). Results revealed a significant main effect forrelationship quality (as rated on the SRI) on the Support,Conflict, and Depth scales of the QRI (see Table 3).Friends classified as ‘‘Supportive’’ on the SRI were alsorated higher on support and depth, and lower in conflict,than were friends classified as ‘‘Ambivalent.’’ Finally, weexamined if friendships characterized as ‘‘ambivalent’’ or‘‘supportive’’ differed on other relationship dimensions.4

There was no significant difference on length of time theyhave known these friends and amount of contact with thesefriends. There was also no significant difference in predict-ability of supportive and ambivalent friends. However,friends classified as supportive had higher ratings of impor-tance than friends classified as ambivalent, although bothtypes of friends were perceived as highly important. Foritems assessing how likely the participant was to go to theirfriend during the three (negative, positive, and neutral)contexts, we found a relationship categorization maineffect for the positive, negative, and neutral contexts. Part-icipants’ were more likely to seek out their supportivefriend than ambivalent friends in positive situations (when‘‘really excited, happy or proud of something’’), duringstressful times (‘‘When you need support such as advice,understanding, or a favor. . .’’), and during ‘‘routine dailyinteractions, conversations, or activities.’’ Despite therelative difference, ratings of likelihood to seek out thefriend were high across both supportive and ambivalentfriends.

2Based on the average age of our sample and RSA beingassessed in the seated position, the relative mean populationRSA value would be 6.6.

3There were 19 participants originally classified as supportivethat increased in negativity at Time 2 such that they no longer metthe initial classification criteria. Likewise, there were 8 parti-cipants that were originally classified as ambivalent that decreasedin negativity at Time 2 such that they no longer met the initial cri-teria. Subsequent analyses were performed dropping these parti-cipants, and all major findings were consistent with what hasbeen reported.

4Despite randomization to the relationship conditions wefound that our groups were not equivalent on numbers of sup-portive and ambivalent friends in their network. That is, indivi-duals randomly assigned to bring in a supportive friend hadsignificantly more supportive network friends (p < .05), whereasindividuals randomly assigned to bring in an ambivalent friendhad significantly more ambivalent network friends (p < .05).Because of this, we reran our main analyses controlling for thenumber of supportive and ambivalent friends, and our physiologi-cal findings were unchanged. Therefore, it is unlikely that thesebroader social network differences were responsible for ourfindings.

282 Holt-Lunstad et al. Annals of Behavioral Medicine

Event Ratings and Postdiscussion Ratings

The second factor that we manipulated was the valenceof the discussion topic. Ratings of topic intensity indicatedno significant group differences (M ¼ 2.9; 3 ¼ moderate),suggesting that the topic selection procedure was effectiveand differences between conditions could not be simplyexplained in terms of the psychological intensity of thepositive and negative events.

A number of other items intended to be manipulationschecks were also included in our Postdiscussion RatingScale. There were several main effects for relationshipclassification (see Table 2). When asked about discussingthe same event with their friend in the past, we found aRelationship�Condition interaction on ratings of upset,F(1, 97) ¼ 7.12, p < .01; x2 ¼ 0.30. In follow-up compari-sons participants perceived their ambivalent friends asmore upsetting in the past than supportive friends whendiscussing the current negative event (p < .05) but notwhen discussing the current positive event.

The IMI

The IMI was completed twice, once after each dis-cussion. Analysis of variance (ANOVA) results revealed amain effect for relationship categorization for ratings on

the Friendliness and Dominance dimension, taken afterboth the neutral discussion and the event discussion (seeTable 3). Supportive friends were perceived as greater infriendliness and less dominant than ambivalent friends dur-ing both discussions.

Anxiety

A mixed ANOVA was used to examine levels of anxi-ety across our four epochs (first baseline, neutral dis-cussion, second baseline, event discussion). There was amain effect for relationship classification during the firstresting baseline, neutral discussion, and the second base-line; however, the final rating taken at the completion ofthe event discussion was not significant (see Table 3). Over-all, the Period�Relationship Classification interactionwas not significant. Thus, ratings of anxiety were consist-ently higher among those who had brought in an ambiva-lent friend than among those who brought in a supportivefriend. We also examined change in anxiety while control-ling for baseline. Results revealed only a main effect for theevent discussion, F(1, 102) ¼ 5.02, p < .05, x2 ¼ 0.16, suchthat discussing negative events was associated withlarger increases in ratings of anxiety than discussing posi-tive events.

TABLE 3

Psychological Variables According to Relationship Quality

Supportive M (SD) Ambivalent M (SD) F x2

SRI Positive Time 1 5.40 (0.63) 4.34 (0.92) 46.59���� 0.30Positive Time 2 5.31 (0.63) 4.66 (0.68) 25.59���� 0.19Negative Time 1 1.03 (0.17) 2.74 (1.03) 140.1���� 0.57Negative Time 2 1.18 (0.30) 2.09 (0.70) 77.11���� 0.42Time known (years) 6.42 (6.28) 6.75 (7.66) 0.06 �0.88Contact (days per week) 4.21 (2.30) 4.31 (2.14) 0.05 �0.91Predictability 4.35 (1.38) 4.33 (1.46) 0.00 �0.99Importance 5.36 (0.99) 4.88 (1.17) 4.81� 0.54Likelihood to seek out friend

Stressful situations 4.97 (1.02) 4.40 (1.23) 6.3� 0.69Positive situations 5.12 (0.99) 4.55 (1.18) 7.24�� 0.67Neutral situations 5.10 (1.07) 4.61 (1.16) 4.6� 0.60

QRI Support 25.64 (2.70) 22.87 (3.27) 21.78���� 0.37Conflict 16.06 (3.08) 22.36 (6.21) 43.2���� 0.54Depth 19.75 (2.76) 17.83 (3.89) 8.5�� 0.18

IMI Friendliness (N) 4.59 (1.13) 3.22 (1.37) 31.01���� 0.46Friendliness (E) 4.52 (1.29) 3.26 (1.72) 17.92���� 0.32Dominance (N) �0.83 (0.63) �0.35 (0.98) 8.63�� 0.18Dominance (E) �0.98 (0.69) �0.62 (1.06) 4.37� 0.09

Anxiety Baseline 1 1.35 (0.40) 1.51 (0.46) 4.19� 0.11Discussion 1 (N) 1.38 (0.40) 1.71 (0.46) 14.71��� 0.33Baseline 2 1.30 (0. 36) 1.55 (0.46) 8.60�� 0.22Discussion 2 (E) 1.69 (0.55) 1.88 (0.58) 2.37 0.05

Note. The scale for SRI ranged from 1 (not at all) to 6 (extremely). SRI ¼ social relationships index; QRI ¼ quality of relationships index; IMI-¼ impact message inventory; N ¼ neutral discussion; E ¼ event (positive or negative) discussion.yp < .10. �p < .05. ��p < .01. ���p < .001. ����p < .0001.

Volume 33, Number 3, 2007 Relationship Quality and Cardiovascular Function 283

Primary Analyses

The major physiological dependent measures wereSBP, DBP, and HR given these measures have been linkedto significant health outcomes (37,38). In addition, becauseblood pressure and HR are multiply determined cardio-vascular endpoints, cardiac impedance derived measuresof PEP, RSA, CO, and TPR were also used as dependentmeasures in an effort to better assess the underlying deter-minants responsible for the changes in CVR across con-ditions.

An average baseline value was calculated for each ofour physiological variables to increase the reliability ofthese assessments (39). During the neutral and event dis-cussions, the participant and friend alternated speakingfor 1 min each so that we had an index of when the partici-pant was speaking versus listening. Because there were nodifferential effects of our manipulations as a function ofspeaking and listening on any of our physiological vari-ables, an average for the neutral and an average for theevent discussion were calculated to increase the reliabilityof these assessments (39). Change scores were then com-puted as an index of reactivity (40). Because basal levelcan affect reactivity scores (41), baseline measures ofphysiological functioning were entered into all of the reac-tivity analyses as a covariate. Finally, effect sizes for signifi-cant findings were calculated using omega-squared (42).

Baseline and Reactivity During the Neutral Task

Because participants were randomly assigned to theconditions of relationship quality and event discussion,we did not expect group differences on any of our cardio-vascular assessments during initial baseline. However, con-sistent with the state anxiety assessment during baseline, wefound a relationship categorization main effect for baselineHR, F(1, 98) ¼ 5.28, p ¼ .02, x2 ¼ 0.11, with higher HRamong those that brought in ambivalent friends than thosewho brought in supportive friends (see Table 4). Consistentwith prior research, there was also a gender main effect forSBP, F(1, 100) ¼ 38.63, p < .0001, x2 ¼ 0.52, with higherresting SBP among men (M ¼ 118.84 mmHg) than women(M ¼ 109.95 mmHg).5

We also examined the impact of the relationship cate-gorization (i.e., supportive, ambivalent) and gender of par-ticipant on CVR during the neutral discussion whilecontrolling for the first baseline. There were no significantmain effects or interactions for SBP, DBP, or HRreactivity.

5Upon inspection, we found a participant who demonstratedextreme baseline data, which was six standard deviations abovethe mean; therefore, this participant’s data were excluded for allanalyses of physiological measures. When this participant wasidentified as an outlier, we reanalyzed our physiological data. Itis important to note that although degree of freedom and meanschanged slightly, none of our findings changed significance.

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284 Holt-Lunstad et al. Annals of Behavioral Medicine

Baseline and Reactivity to Discussing Positive or

Negative Events with Supportive or Ambivalent Friends

Preliminary analyses of the second baseline replicatedthe gender main effects for SBP, F(1, 102) ¼ 33.86,p < .0001, x2 ¼ 0.48, and replicated the relationship maineffect for HR, F(1, 98) ¼ 6.98, p < .01, x2 ¼ 0.15. Due tothe lack of relationship categorization differences in reac-tivity during the neutral task, simple change scores (eventdiscussion� second baseline) were used while controllingfor gender and second baseline for the remainder of ouranalyses.

Even though preliminary analyses showed that parti-cipants perceived the positive and negative events to beequally intense, a significant main effect was found forSBP reactivity, F(1, 100) ¼ 7.74, p < .01, x2 ¼ 0.24. Thenegative event discussion evoked greater SBP reactivitythan the positive event discussion. These data are consist-ent with research suggesting a negativity bias on physio-logical function (43).

We next evaluated our primary hypotheses about thecontext in which ambivalent relationships may be detri-mental. Results revealed a statistical interaction betweenrelationship quality and the event topic on reactivity forSBP, F(1, 100) ¼ 13.05, p ¼ .0005, x2 ¼ 0.36; see Figure 1.Consistent with the support interference hypothesis, con-trasts reveal participants exhibited greater SBP reactivitywhen discussing a negative event with an ambivalent friend(M ¼ 9.6 mmHg D) than with a supportive friend(M ¼ 5.4 mmHg D), F(1, 48) ¼ 8.72, p < .01, x2 ¼ 0.70.Further, among participants interacting with an ambiva-lent friend, those discussing a negative event displayedgreater SBP reactivity (M ¼ 9.6 mHg D) than did those dis-cussing a positive event (M ¼ 3.4 mHg D), F(1,49) ¼ 20.99, p < .0001, x2 ¼ .90. There was no significantdifference between discussing positive and negative eventswith a supportive friend. These results, combined withour results from the neutral interaction, suggest thatambivalent relationships are not just general sources of ten-sion during interactions but may be distressing primarily in

the context of seeking support during stress. However,when discussing positive events there was a significant dif-ference between discussions with supportive and ambiva-lent friends, F(1, 50) ¼ 5.24, p < .05, x2 ¼ 0.19.Unexpectedly, discussing a positive event with an ambiva-lent friend was associated with lower reactivity.

Follow-Up Analyses

Clarification of SBP Finding During

Positive Discussions

Given the unexpected finding that individuals discussinga positive event with an ambivalent friend showed the lowestlevels of reactivity we performed several focused follow-upanalyses. Two possible explanations for this finding are thatparticipants were able to get more excited telling their sup-portive friend about something fantastic that occurredrecently or that participants interacting with ambivalentfriends disengaged from the positive event discussion task.To test these explanations, a repeated measures ANOVA ofthe neutral reactivity and the event reactivity was exploreddirectly contrasting neutral and positive discussions withambivalent friends and supportive friends. Results revealeda significant Relationship�Period interaction, F(1, 49) ¼4.39, p < .05, x2 ¼ 0.16. Upon further inspection, there wasno significant difference in reactivity during the neutral taskand the positive discussion for those talking to theirsupportive friend. In contrast, our data show that there wasa significant decrease in reactivity between the neutral task(M ¼ 8.16 mmHg) and the positive event condition(M ¼ 3.37 mmHg) for those with ambivalent friends,F(1, 25) ¼ 7.78, p ¼ .01, x2 ¼ 0.33. Overall, these data donot support the possibility of exaggerated reactivity amongthose discussing positive events with a supportive friend;rather, the data suggest a possible disengagement from thetask for those interacting with ambivalent friend.

Analyses of Underlying Determinants of Heart Rate and

Blood Pressure

We followed up our significant results by analyzing theimpedance-derived measures associated with the underly-ing determinants of HR (i.e., PEP and RSA) and BP(i.e., TPR, CO). There was also a significant difference dur-ing the first baseline period for relationship categorizationon RSA, F(1, 92) ¼ 17.91, p < .0001, x2 ¼ 0.35, andsecond baseline period, F(1, 92) ¼ 15.92, p < .0001,x2 ¼ 0.32, with greater RSA among those who broughtin a supportive friend than those who brought in anambivalent friend. To examine the potential mediatingeffect of RSA, we reanalyzed the baseline HR data usingRSA as a covariate and the effect became nonsignificant.This was consistent across the first, F(1, 91) ¼ 0.04,p ¼ .84, and the second, F(1, 91) ¼ 0.03, p ¼ .86, baseline.These data suggest that the baseline differences in HR aredue to parasympathetic influences on the heart. There were

FIGURE 1 Systolic blood pressure reactivity according torelationship classification and discussion.

Volume 33, Number 3, 2007 Relationship Quality and Cardiovascular Function 285

no other significant main effects or interactions for RSA,PEP, TPR, or CO (see Table 4 for details). As a result,no clear evidence of the underlying determinants for theRelationship�Event interaction for SBP was found.6

Analysis for Potential Mediation

Because we found a significant interaction on the Post-discussion Rating of past upset between relationship qualityand event discussion valence that was in the same directionas our interaction effect for SBP reactivity, we did explora-tory analyses to examine potential mediation. Thus, wewere interested in the PDR item that asked ‘‘When discuss-ing this event with this person in the past, how upsetting hasyour friend been?’’ Results revealed that past upset was sig-nificantly correlated to SBP reactivity (p < .05). Becausethe primary stress-enhancing effect was found in the nega-tive event discussion, we repeated this analysis looking atambivalent-supportive friend differences only in the nega-tive event discussion. The previously significant simplemain effect was rendered nonsignificant when controllingfor perceptions of how upsetting they had been in the past.Thus, past upsetting feelings toward the friend when theyhad discussed the current negative event mediated therelationship quality differences on SBP reactivity.

DISCUSSION

The purpose of this study was to address two questionsregarding the specificity of the association between socialrelationships and health. First, are ambivalent relationshipsassociated with health relevant processes? Second, underwhat conditions are ambivalent ties detrimental? Our datasuggest that interactions with ambivalent ties were generallyviewed more negatively and that individuals interactingwith an ambivalent friends showed greater SBP reactivityprimarily when disclosing a negative personal event. More-over, this effect was mediated by how upsetting the friendhad been in the past when discussion the negative event.Thus, to the extent that SBP reflects a detrimental health-relevant process, ambivalent relationships are a potentiallynegative influence on health, especially during discussion ofprior stressful personal events.

One main goal of this study was to evaluate two broadmechanisms potentially linking ambivalent ties to detri-mental outcomes. First, it is possible that individuals areunable to receive or perceive effective social support fromambivalent relationships during times of need. Second,social interactions with ambivalent network ties may gener-ally be associated with significant levels of interpersonalstress (44). Our main finding for the physiological data,highest SBP reactivity associated with discussing negative

events with the ambivalent friend, is consistent with thesupport interference hypothesis. Given the joint positivityand negativity associated with ambivalent relationships itmay be that when participants seek out support from anambivalent friend that the support received is not trustedor they may feel blamed instead of understood. It is alsopossible that ambivalent friends may be perceived as morecritical given that they were rated as lower in warmth andhigher in control than relationships characterized assupportive. Together, our data suggest that support fromsuch ambivalent ties in times of stress may be less effective,with such effects being mediated by how upsetting thefriend had been in past discussions of the negative event.These data may also suggest a more context-specificinterpretation of the stress-enhancing hypothesis such thatambivalent friends may be associated with increased inter-personal stress only when discussing negative events.

Although our reactivity data appear consistent withthe support interference hypothesis, other data indicatethat we cannot discount the stress-enhancing hypothesisas our data also demonstrate that ambivalent relationshipsmay have more subtle effects on physiological processes.For example, self-reports of anxiety were consistentlyhigher among those who brought in an ambivalent friendthan a supportive friend across every portion of the experi-ment. We also found consistently higher levels of HR andlower RSA among those who brought in ambivalentfriends than those who brought in supportive friends.Because baseline measures were assessed with only a cur-tain separating them from their friend, it suggests thatthe mere presence or the anticipation of interacting withan ambivalent friend may be taxing for these individuals.Therefore, those paired with ambivalent friends may havebeen unable to fully relax and hence regulate their cardio-vascular system to the extent participants with supportivefriends were able to do. It is important to mention thatalthough RSA is a marker of vagal (parasympathetic) con-trol of the heart (45), respiratory rate and amplitude caninfluence RSA independent of vagal control (46). Somestudies suggest that ‘‘corrected’’ and ‘‘uncorrected’’ assess-ments produce similar conclusions under stress paradigms(47–49). However, one limitation of our findings is thatwe do not have respiratory data to directly examine thisissue. Therefore, it is possible that participants whobrought in an ambivalent friend may have had lowerRSA than those who brought in a supportive friend simplybecause they were breathing at a faster rate during thebaseline period. Future research will be needed to examinethe plausibility of this alternative explanation.

One relatively unexpected but interesting finding indi-cated the lowest levels of reactivity occurred among thoseinteracting with ambivalent friends in positive contexts.Our ancillary analyses suggest the possibility that indivi-duals may have disengaged from the discussion asevidenced by their lower reactivity compared to the neutraldiscussion condition. Relevant research by Gable and

6The lack of findings for impedance-derived measures poten-tially mediating blood pressure changes may be due to the greatermeasurement error inherent in deriving CO and TPR.

286 Holt-Lunstad et al. Annals of Behavioral Medicine

colleagues (50) suggests that this disengagement may haveimportant intra-and interpersonal consequences. Socialcapitalization, telling others about positive events in one’slife, is thought to be associated with greater positive affectover and above the positivity associated with the event.There are multiple potential mechanisms that influence selfand relationship processes including: the process of relivingthe event can boost positive affect, sharing the eventstrengthens the relationship, and=or it can serve to boostself-esteem by being seen favorably in the eyes of others.Thus, if individuals disengage when discussing positiveevents with ambivalent friends, they may not experiencethe upward spiral of positive affect and well-being (51).However, such explanations are speculative and future stu-dies will be necessary to examine these possibilities.

Overall, our data suggest that ambivalent relationshipsdo not afford the same emotional and physical benefits thatsupportive relationships do and may be potentially detrimen-tal. One possible reason for these deleterious influences isthat general perceptions of the relationship may be drivingparticipants’ interpretation of the situation. A person’s his-tory of experiences (positive and=or negative) with a friendprovides a lens or schemata by which current and futureevents are interpreted. For example, an ambivalent friendwho is behaving supportively in our study may be assumedto be ‘‘trying to look good for the experimenters.’’ Thus, itmay not be anything in particular the friend is doing in themoment but rather the individual’s perception of that friendthat may be driving the response. Our mediational analysesare consistent with this interpretation as how upsetting thefriend had been in the past discussions of the negative eventappeared responsible for the differences in SBP reactivity.Taken together, these findings suggest that one’s historyand overall perception of the friend may be more importantthan the behavior during the interaction.

There are several limitations of this study that warrantdiscussion. The first concerns the generalizability of thesample. This study only included college-age participantswho were healthy. In addition, our sample primarily com-prised White participants. The extent to which these find-ings can be expanded to other ages, socioeconomicstatus, health status, and ethnicities cannot be determined.In addition, all participants were required to bring in asame-sex friend. It is possible that participants may havereacted differently if they were interacting with an oppositesex individual and=or someone of a different relationshiptype (i.e., romantic partner, sibling, coworker). It is alsopossible that the effect of relationship type on CVR maybe underestimated in this study due to some degree ofimprecision in the classifications (see footnote 3).

Another limitation of this study is the ecological val-idity to social support or disclosure processes. It is possiblethat the structured (alternating minutes) conversationreduced the naturalness and flow of the discussionsbetween friends. Although it is difficult to determine pre-cisely the extent to which the naturalness was reduced,

we did behavioral code the videotaped interactions,7 andthese data suggest that any effect this may have had wasequivalent when discussing events with supportive andambivalent friends. Alternatively it is possible that peoplemay not actually choose to seek out their ambivalent friendwhen they need support. Although we found that the like-lihood to seek out supportive friends was relatively higherthan ambivalent friends, ratings of likelihood were still(between moderate and very) high.

It is also unclear whether having ambivalent friendswould be better or worse than having no friends at all(social isolation, e.g., 52). Although both may be bad, con-flict and support are separate dimensions (53). There aresome data to suggest that negativity in social relationshipshas a stronger effect than support (26,54,55). Alternatively,because we find that most of our participants have bothsupportive and ambivalent individuals in their network, itis also possible that their supportive relationships can buf-fer the negative effects of having ambivalent relationships(see 56). It is also possible that individuals may benefitfrom noninterpersonal disclosure such as diary=journalentries (57,58) and prayer (59). Future research will beneeded to directly contrast these possibilities.

We should also note that the actual health relevance of thisstudy is less clear, because it was a cross-sectional study usingyoung participants. Many of the health outcomes predicted bysocial relationships, including cardiovascular disease, developslowly over time. Despite our young sample, the average lengthof time they had known their friend was 6.6 years—approxi-mately one third of their lifetime. Our data attest to the stabilityof relationships even among young college students who aretypically in a transitional stage socially. Due to the stabilityof many other types of social relationships (e.g., familial ties,spouse; see 60), the health effects of these ambivalent socialrelationships may be more important. It is also possible thatany potential negative impact of ambivalent relationshipsmay be limited if individuals can avoid contact with them.Our data, however, revealed no difference in the amount ofcontact participants have with ambivalent and supportivefriends. Future studies examining ambivalent feelings amongmarried couples may be especially promising given the stronglinks of marriage to health (61,62). Likewise, studies examiningambivalent relationships among older adults or clinical popu-lations may also provide insight on the relative impact of socialrelationships in more health relevant populations.

Despite the limitations, this study has a number ofstrengths. First, the increased ecological validity is associa-ted with the use of an existing friendship. Many prior lab-oratory studies examining social support have been limited

7We had two raters, blind to condition, rate the videotapedinteractions. Reliability between the coders for each (between.41 and .69) was significant (p < .05). Based on these ratings, itappears that the structured nature of the conversation did not dif-ferentially impact the flow of conversation. Interested readers canget a copy of these analyses by contacting the primary author.

Volume 33, Number 3, 2007 Relationship Quality and Cardiovascular Function 287

(63) by the use of strangers, confederates, or the exper-imenter to operationalize support, in that they fail to cap-ture nuances associated with existing relationships (i.e.,one’s history with that person). A further strength of thisstudy is that we randomly assigned participants to bringin a particular type of relationship (supportive or4ambivalent) from their larger network. By randomlyassigning the type of friend (supportive=ambivalent) forindividuals to bring in as part of the experiment, we areable to prevent individuals from self-selecting their friendand potentially biasing our results. Last, these data werestrengthened by independent confirmation of relationshiptype and the inclusion of standardized measures of basicinterpersonal dimensions (i.e., IMI).

Overall, these results may have important implicationsfor the conceptualization andassessment of social relation-ships in the health domain. Simply assessing levels of socialsupport (e.g., positivity) may obscure the natural hetero-geneity that exists in people’s relationships by ignoring co-occurring levels of negativity. This point may be especiallyimportant to consider in developing social support interven-tions (10). Our results suggest that implementing a supportintervention (without regard to extent of positivity andnegativity within that relationship) could potentially leadto detrimental outcomes. More generally, it is our hope thatsuch a multidimensional approach to the study of socialrelationships may be useful in understanding the underlyingassociations between social relationships and health.

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