Load dependence of changes in forearm and peripheral vascular resistance after acute leg exercise in man.

Abstract

1. It is known that acute exercise is often followed by a reduction in , compared with the control day. Systolic and mean pressure also fell (non-significantly) after 45 min; heart rate was significantly elevated for the whole hour of recovery (at 60 min, +7'23 beats min'). No changes in post-exercise blood pressure and heart rate were observed on the days of moderate and minimal exercises. 4. An increase in cardiac index was observed after maximal exercise compared with control (at 60 min, 2'6 + 0'3 vs. 1'9 + 0'2 1 min' m-2). This was entirely accounted for by the persistent increase in heart rate, with no significant alteration in stroke volume after exercise on any day. 5. Systemic vasodilatation was present immediately after maximal exercise compared with control (after a 5 min rest, total peripheral resistance was 17'9 + 3S5 vs.27'8 + 3-4 mmHg (1 min')-' on the control day) and lasted at least 60 min (at 60 min, 23'3 + 3'5 vs. 31'0 + 3'8 mmHg (1 min`)`o n the control day). No significant changes in total peripheral vascular resistance were observed after moderate or minimal exercise days. 6. After this predominantly leg exercise, minimal and moderate loads significantly increased forearm vascular resistance with respect to baseline pre-exercise resistance (at 60 min, +26'7 % and +20'5%, respectively), but there were no significant differences with respect to the control day; maximal leg exercise significantly decreased the forearm vascular resistance for 1 h (at 60 min, -17'2 % vs. baseline pre-exercise value and -46'0 % compared to the control day). This suggests that prolonged forearm vasodilatation occurred only after higher exercise loads.Hypotension has been shown to follow short periods of exercise

Potential causes, mechanisms, and implications of post exercise hypotension

“…Only one study has reported a difference in the hypotensive response to different exercise intensities. In that study, Piepoli et al 72 found a decrement only after maximal cycle exercise (5 min stages of 25 Watt increments) when compared with moderate (5-min stages of 12.5 Watt increments) and minimal (constant 50 Watt) intensity exercise in normotensive sedentary volunteers. However, in sedentary individuals, maximal exercise could more adversely affect the haemodynamic response to exercise than in the other studies.…”

“…10,11,19,22,24,[31][32][33]35,41,[43][44][45][59][60][61]63,71,72 Treadmill exercise at similar intensities has also been documented to elicit PEH. 14,15,20,25,34,40,[55][56][57][58] Direct comparisons of the effect of exercise intensity have, for the most part, found that PEH occurs independent of exercise intensity.…”

“…In rats, PEH has been documented following treadmill exercise at 30 m/min and 10% grade, 68,72 70% V · O 2 Max , and spontaneous, self selected running. 67 Stimulation of the biceps femoris and gastrocnemius muscles at current intensities of 3 to 25 mA in the awake rat has been found to induce PSH.…”

“…The onset of hypotension following exercise has been found to occur within the initial minutes after exercise 33,72,79 or at some time point between 30 min and 1 h following exercise. 9,16,31,44,49,57,61 Most studies have measured blood pressure for only 1-2 h following exercise 12,13,16,20,22,23,25,34,[36][37][38][39]55,58,75 and the majority of these have found a nadir in blood pressure during that time with a return or trend towards baseline pressure at the cessation of measurement.…”

The effects of exercise intensity on post exercise hypotension

“…[3][4][5][6][7][8][9][10] Treadmill exercise at similar intensities has also been shown to elicit PEH. Direct comparisons of the effect of exercise intensity on PEH have been limited to 40 and 70% of maximal exercise.…”