The effect of acute aerobic exercise on stress related blood pressure responses: A systematic review and meta-analysisIntroductionMethodsSearch strategy and inclusion criteriaMeta-analysisQualitative examination of moderatorsResultsPost-exercise stress related BP responseParticipant characteristicsDesign characteristicsExercise characteristicsStressor characteristicsDiscussionPotential mechanismsImplicationsConclusions and recommendations for future studiesReferencesDTD 5The effect of acute aerobic exercise on stress related blood pressureresponses: A systematic review and meta-analysisMark Hamera,*, Adrian Taylorb, Andrew SteptoeaaDepartment of Epidemiology and Public Health, Psychobiology Group, University College London, 1-19 Torrington Place, London WC1E 6BT, UKbSchool of Sport & Health Sciences, University of Exeter, UKReceived 2 February 2005; accepted 4 April 2005AbstractThe beneficial impact of regular exercise on cardiovascular health is partly mediated by psychobiological mechanisms. However, the effectof acute exercise on psychobiological responses is unclear. Thus, we performed a systematic review of randomised controlled trials (RCTs)that examined the effect of acute aerobic exercise on blood pressure (BP) responses (the change from baseline to stress) to psychosociallaboratory tasks. Fifteen RCTs met inclusion criteria of which ten demonstrated significant reductions in post-exercise stress related BPresponses compared with control (mean effect sizes for systolic and diastolic BP, 0.38 and 0.40). Studies involving greater exercise dosestended to show larger effects, with the minimum dose to show a significant effect being 30 min at 50%˙VO2max. No other moderators emergedfrom the examination of participant characteristics, research designs and stressor characteristics. In conclusion, an acute bout of aerobicexercise appears to have a significant impact on the BP response to a psychosocial stressor.# 2005 Elsevier B.V. All rights reserved.Keywords: Cardiovascular health; Aerobic exercise; Blood pressure response; Mental stress; Meta-analysis1. IntroductionEmerging and recently published scientific evidence hasdemonstrated a prospective relationship between heightenedblood pressure (BP) response to psychosocial stress andhypertension development (Carroll et al., 2001, 2003;Matthews et al., 2004) and progression of carotid athero-sclerosis (Barnett et al., 1997; Kamarck et al., 1997;Jennings et al., 2004). Cardiovascular reactivity tests havetherefore been proposed as a possible clinical tool fordetecting the likelihood of hypertension (Turner, 1994) andprovide a useful research paradigm for understandingpsycho-physiological mechanisms. The potentially detri-mental role of stress highlights the importance of examiningand implementing healthcare interventions that control theimpact of stress on health. A variety of practical interven-tions for stress management (to control physiological stress–reactivity) have been proposed including aerobic exercise.Exercise has been proposed to reduce sympathetic responsesto stress (Crews and Landers, 1987) thereby limitingexposure to repeated pathophysiological hypersympatheticarousal. Although there is a general consensus that chronicaerobic exercise (a physiological adaptation to exercisetraining) exerts a significant anti-hypertensive effect(Whelton et al., 2002) and acute exercise (the physiologicalresponse to one bout of exercise) results in post-exercisehypotension (Pescatello and Kulikowich, 2001), therelationship between chronic/acute exercise and stressrelated BP responses is less clear. Investigators havegenerally given much more attention to the effects ofchronic exercise on stress related cardiovascular responses(Crews and Landers, 1987) due to the cross-stressoradaptation hypothesis. However, repeated exposure to acutebouts of exercise with resulting multiple episodes of reducedcardiovascular reactivity may cumulatively result incardiovascular health benefits. Earlier studies that examinedthe effects of chronic exercise on stress related BP responsesgenerally used cross-sectional designs which showed rathersmall and inconsistent effects (Crews and Landers, 1987).www.elsevier.com/locate/biopsychoBiological Psychology xxx (2005) xxx–xxx* Corresponding author. Tel.: +44 20 7679 1804; fax: +44 20 7916 8542.E-mail address: [email protected] (M. Hamer).0301-0511/$ – see front matter # 2005 Elsevier B.V. All rights reserved.doi:10.1016/j.biopsycho.2005.04.004Cross-sectional studies are potentially confounded by anumber of variables, such as psychological and geneticfactors, therefore, further studies have used randomisedcontrolled trials (RCTs) to examine chronic exercise effects.However, more recent findings from RCTs have also providedrather mixed and disappointing results. For example, Kinget al. (2002) demonstrated a significant reduction in the BPresponse to a speech task after a 12-month-exerciseintervention in caregivers, although Georgiades et al.(2000) did not see any changes in stress related BP responsesafter a 6-month intervention in hypertensive participants,despite observing reductions in absolute BP. Steffen et al.(2001) have also demonstrated an absolute reduction in BPduring daily life stressors after a 6-month-exercise interven-tion, although stress related BP responsiveness was notreported. One potentially confounding factor is that thebenefits of exercise for reducing stress related BP responsesare confined to a post-exercise window. Thus, if mental stresstesting is performed in chronically trained individuals outsidethis window it is possible that no effects will be observed.Therefore, the main benefits of chronic exercise may be due tothe fact regular exercisers are more often in the post-exercisewindow when they encounter stressors, in addition todemonstrating lower absolute BP levels. Given the potentiallyconfounding impact of acute exercise it is important to studychronic and acute effects separately and also how they mayrelate to one another. The present review considers the lesswell-explored issue of acute exercise as a modulator of stressrelated BP responses. All of the reviewed studies were RCTsand involved an acute bout of aerobic exercise followed by acardiovascular stress–reactivity test that was compared with anon-exercise control condition.2. Methods2.1. Search strategy and inclusion criteriaThe present review expanded on a recent review ofliterature (Taylor, 2000) that examined the