Potential causes, mechanisms, and implications of post exercise hypotension

Abstract

Post exercise hypotension (PEH) is a phenomenon of a prolonged decrease in resting blood pressure in the minutes and hours following acute exercise. Knowledge of PEH is potentially useful in designing first line strategies against hypertension as well as allowing a further understanding of blood pressure regulation in both Keywords: blood pressure; vascular; cardiac; opioids; exercise Blood pressure responses during exerciseDuring dynamic exercise, cardiac output increases dramatically to ensure adequate perfusion to the working musculature. This increase is achieved by a withdrawal of parasympathetic tone (causing an increased heart rate and contractility), an increase in sympathetic activity (directly and indirectly increasing heart rate and contractility) and pronounced vasoconstriction of the venous vasculature (causing a greater venous return and therefore stroke volume). In parallel, the need for increased blood flow and oxygen delivery to the exercising muscle is achieved through regional vasodilation of those arterioles supplying blood to the exercising tissue in combination with a vasoconstriction of arterioles, which perfuse non-essential tissues. Although the mechanism of vasodilation at the onset of exercise is not fully understood, many compounds (eg, potassium, adenosine, nitric oxide, etc) have been implicated in the exercise induced changes. Contraction of the active muscle mass also assists in returning blood towards the heart. This 'muscle pump' effect further increases venous return and stroke volume.Increased cardiac output and vasoconstriction in non-exercising vascular beds increases systolic blood pressure (SBP), but the significant vasodilation at the exercising muscle beds helps to buffer this increase and results in a minimal rise in diastolic blood pressure (DBP). As exercise continues Correspondence: JR MacDonald, McMaster University Medical Centre, Room 4U18, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada. E-mail: jaymacȰmcmaster.ca health and disease. Following a brief review of blood pressure responses to exercise, this paper will provide a current and comprehensive summary of PEH and integrate the current state of knowledge surrounding it.

Accumulation of 30 min of moderately intense physical activity is a clinically meaningful treatment to reduce systolic blood pressure in prehypertension

“…11 Consistent with this literature, Park et al 8 previously found that the duration of postexercise hypotension following accumulation of 40 min exercise was associated with the magnitude of change in autonomic function, as assessed by frequency domain measures of heart rate variability. In the present study, they additionally explored the possibility that short-term change in autonomic function might also contribute to blood pressure decrease during rest between exercise bouts.…”

Time of day for exercise on blood pressure reduction in dipping and nondipping hypertension

“…The reduction in blood pressure following a single bout of exercise has been reported to persist for up to 11-12 h under free-living conditions for systolic blood pressure (5-8 mmHg) and/or up to 4-8 h for diastolic blood pressure (6-8 mmHg) 13À17 5. Exercise treatment prior to the period of highest blood pressure elevation may result in a more attenuated response because greater blood pressure reductions can be found in higher pressures 18 What this study adds 1. This study observed the effects of the TOD for exercise on the reduction of ambulatory blood pressure in dipping and nondipping hypertension (a) Evening exercise exhibited a greater reduction in nighttime systolic blood pressure for Non-Dippers than for Dippers (b) Morning exercise exhibited similar daytime systolic blood pressure reductions for Dippers and Non-Dippers (c) Morning and evening exercise treatments exhibited similar 24 h systolic blood pressure reduction for both dipping and nondipping hypertension 2.…”

“…[13][14][15][16][17] Presenting an exercise treatment prior to the period of highest blood pressure elevation may result in a more attenuated response because greater blood pressure reductions can be found in higher pressures. 18 Given this fact, morning exercise may be more effective in reducing the elevated daytime pressures in dipping and nondipping hypertension whereas evening exercise may be more effective in reducing the elevated nighttime pressures in nondipping hypertension. Thus, the study of the time of day (TOD) for exercise may be a conceptual approach for a more individualized exercise prescription in nondipping hypertension.…”

Effect of fractionized vs continuous, single-session exercise on blood pressure in adults

“…2 PEH has been reported to be B7-14 mm Hg, can occur within 5 min after exercise, and may persist for up to 22 h. 2,3 Exercise sessions as short as 10 min can produce PEH. 2,4,5 This may have important clinical application for exercise prescription, especially for individuals with time constraints that preclude engaging in traditional, longer exercise sessions (for example, 30-40 min). In addition, fractionized exercise may provide a means to capitalize on the benefits of an acute bout of exercise, even if relatively short (for example, p10 min), multiple times per day.…”

“…4 In addition, because we measured BP hourly, and not acutely after exercise, we may have underestimated the total PEH effect of the fractionized exercise condition, particularly after the last two 3 Â 10-min exercise sessions. 2 The lack of a BP reduction after the 1 Â 30-min exercise session could be due to inconsistent PEH responses in normotensives or to exercise timing. 2,10,11 Although PEH has been observed in normotensives immediately after exercise, 2 lower BP throughout the day after a morning exercise session was observed in hypertensives, but not in normotensives.…”