Review: Physical activity lowers blood pressure
ACP J Club. 1992 Nov-Dec;117:80. doi:10.7326/ACPJC-1992-117-3-080
Arroll B, Beaglehole R. Does physical activity lower blood pressure: a critical review of the clinical trials. J Clin Epidemiol. 1992 May;45:439-47.
To examine the effect of physical activity on normal and elevated blood pressure through a review of the literature.
A MEDLINE search for English-language articles using the terms blood pressure, hypertension, exercise, and exertion. Further studies were sought through the bibliographies of relevant articles.
Experimental studies of physical activity among humans were included if they had been published since 1980 and not reviewed by Seals and Hagberg (1984), the patients had no systemic disease except hypertension, and blood pressure (BP) was a main outcome. 22 studies were selected.
Study methods, patient characteristics, group mean BP (and standard deviation [SD]) in mm Hg, and details of exercise regimens were extracted.
13 studies analyzed habitual activity and included a control group (7 were randomized controlled trials); 6 studies had no control group, and 3 studies investigated only 1 episode of physical activity. More men than women participated; 10 studies included or had only normotensive persons in them.
Overall, 21 studies reported reduced resting, post-exercise systolic (S) BP, and all reported reduced diastolic (D) BP. Among the 13 controlled studies, in those whose participants had initial SBP < 139, the mean reductions in SBP and DBP were 7.0 (SD 3.1) and 5.8 (2.7), respectively. In studies in which participants had initial SBP ≥ 139, the mean reductions were 10.3 (7.3) in SBP and 7.5 (3.0) in DBP. For the 5 studies using better methods, the mean reduction in BP after exercise was smaller than for 7 poorer-quality studies (mean reductions SBP 6.4 [4.4] vs 9.4 [7.1]); DBP reductions were similar (6.9 [2.7] vs 6.5 [3.0]). In 2 controlled studies with blinded measurement of BP, reductions were smaller (SBP 6.0, DBP 4.0). In 3 trials of low-intensity habitual activities (e.g., walking), after-exercise reductions in SBP and DBP were 11.3 (10.3) and 7.5 (4.0), respectively, whereas in 6 trials of higher-intensity activities (e.g., jogging), after-exercise reductions in SBP and DBP were 9.0 (4.2) and 7.3 (2.3), respectively. A greater reduction in BP was reported with more frequent training sessions and over a longer period (duration of training, 1 session to 9 mo).
Exercise is an effective strategy for reducing resting blood pressure in normotensive and hypertensive participants. Reductions are smaller in the higher-quality studies.
Source of funding: Not stated.
For article reprint: Dr. B. Arroll, Department of General Practice, School of Medicine, University of Auckland, Private Bag, Auckland 1, New Zealand.
Arroll and Beaglehole have done a criteria-based review of recent studies that address the effectiveness of exercise in lowering blood pressure. In this analysis, studies are classified as to their methodologic strengths and weaknesses, and a synopsis of results is presented. The authors concluded that physical activity lowers blood pressure and that this effect is independent of weight reduction, a confounding variable in many studies.
It should be noted, however, that the summary reductions in pressures are simply the sum of the mean reductions in each study divided by the number of studies, so that the studies including large numbers of patients contributed no more information than those with few patients (in methodologic terms, there was no weighting). The consistency of the results of the studies, however, supports the conclusion that some lowering of blood pressure occurred.
What is the clinician to recommend? It is generally accepted that nonpharmacologic approaches to the management of hypertension, such as weight reduction, sodium restriction, and exercise, have a role both as the primary intervention and as adjuncts to pharmacologic treatment (1), especially in mild hypertension. It is likely that the efficacy of these interventions, that is, the effect in motivated patients who can be compliant with such regimens, may be comparable to pharmacologic therapy, even in elderly patients (2).* Given concerns about side effects, costs, and negative metabolic effects of antihypertensive medications, the identification of these patients and their treatment by nonpharmacologic means should be a goal of the primary care provider.
Richard A. Davidson, MD, MPH
University of FloridaGainesville, Florida, USA
Richard A. Davidson, MD, MPH
University of Florida
Gainesville, Florida, USA
*See abstract and commentary for Weight reduction, dietary sodium restriction, and an increase in exercise reduced mildly raised blood pressure in older patients.— The Editor