Exercise Above Critical Power Elicits Greater Post-Exercise Hypotension than Heavy Exercise Performed to Task Failure.

Abstract

We have previously shown that critical power (CP) is a key threshold determining the magnitude of post-exercise hypotension (PEH); however, whether this finding depended upon 1) the attainment of task failure or 2) could be augmented by increasing exercise duration above CP remained unclear. To determine 1) whether a similar magnitude of PEH would occur after exhaustive heavy versus supra-CP exercise, and 2) whether the magnitude of PEH depended upon exercise duration above CP. Eighteen healthy participants (14 males and 4 females) performed 3 criterion trials involving exercise performed to task failure at power outputs that elicited exhaustion in either 6 min ( WR6 ), 12 min ( WR12 ), or at a heavy intensity (50%ΔGET-CP, halfway between the gas exchange threshold [GET] and CP) and all were followed by 60 min of seated recovery. Although time to exhaustion was greatest in 50%ΔGET-CP (2606 ± 732 s) versus WR12 (790 ± 67 s) and WR6 (397 ± 42 s, P < 0.001), the magnitude of PEH, as indicated by the change in mean arterial pressure (MAP) from baseline ( WR6 vs 50%ΔGET-CP: -12.9 ± 3.3 mm Hg vs -9.4 ± 3.6 mm Hg; WR12 vs 50%ΔGET-CP: -12.8 ± 3.7 mm Hg vs -9.4 ± 3.6 mm Hg, main effect P < 0.01) was greater in WR6 and WR12 than 50%ΔGET-CP (all P < 0.05). However, the changes in MAP were not different between WR6 and WR12 ( P = 0.90). These findings reinforce the notion that CP is a key threshold determining the magnitude of PEH. Specifically, the magnitude of PEH after exhaustive supra-CP exercise remained greater than heavy exercise when the heavy bout was performed to task failure.