Run for Your Life: A Meta‐Analysis of the Effects of Exercise Intensity on Cardiovascular Outcomes in a Rat Model of Hypertension

Abstract

ObjectiveHypertension increases the risk of pulmonary embolism, stroke, heart attack, and death. To prevent these events in hypertensive patients, regular exercise has been recommended as a nonpharmacological intervention for decades, but it is still not well understood whether cardiovascular benefits vary with exercise intensity. In this meta‐analysis, we explored the effect of treadmill running intensity on systolic blood pressure (SBP), mean arterial pressure (MAP), and resting heart rate (RHR) in a rat model of hypertension, known as spontaneously hypertensive rats (SHR).MethodsA SciFinder Scholar database search returned 817 comparative studies, of which 72 (1505 rats) were included for quantitative analysis. Studies were characterized as low, moderate, or high intensity based on treadmill speed setting or, where available, %VO2max. Aggregate means and standard errors for SBP, MAP, and RHR were extracted and subjected to one‐way ANOVA with post‐hoc Tukey’s test using GraphPad Prism 9.ResultsWhen compared to sedentary hypertensive controls, both low and moderate‐intensity treadmill exercise yielded significant reductions in SBP, MAP, and RHR, but high‐intensity exercise did not. Although the greatest improvement in SBP, MAP, and RHR resulted from low‐intensity treadmill exercise, no statistically significant difference was found between training intensity levels for these cardiovascular outcomes.ConclusionsLow and moderate‐intensity, steady‐state treadmill sessions over several weeks reduced blood pressure and resting heart rate in hypertensive subjects. The failure of high‐intensity exercise to improve cardiovascular outcomes may suggest a role played by oxidative stress and merits further investigation. Overall, these preliminary results suggest that even low‐intensity exercise may serve as a beneficial tool that positively impacts cardiovascular outcomes in chronic hypertension.