Effect of acute exercise-induced fatigue on maximal rate of heart rate increase during submaximal cycling.
Different mathematical models were used to evaluate if the maximal rate of heart rate (HR) increase (rHRI) was related to reductions in exercise performance resulting from acute fatigue. Fourteen triathletes completed testing before and after a 2-h run. rHRI was assessed during 5 min of 100-W cycling and a sigmoidal (rHRIsig) and exponential (rHRIexp) model were applied. Exercise performance was assessed using a 5-min cycling time-trial. The run elicited reductions in time-trial performance (1.34 ± 0.19 to 1.25 ± 0.18 kJ · kg(-1), P < 0.001), rHRIsig (2.25 ± 1.0 to 1.14 ± 0.7 beats · min(-1) · s(-1), P < 0.001) and rHRIexp (3.79 ± 2.07 to 1.98 ± 1.05 beats · min(-1) · s(-1), P = 0.001), and increased pre-exercise HR (73.0 ± 8.4 to 90.5 ± 11.4 beats · min(-1), P < 0.001). Pre-post run difference in time-trial performance was related to difference in rHRIsig (r = 0.58, P = 0.04 and r = 0.75, P = 0.003) but not rHRIexp (r = -0.04, P = 0.9 and r = 0.27, P = 0.4) when controlling for differences in pre-exercise and steady-state HR. rHRIsig was reduced following acute exercise-induced fatigue, and correlated with difference in performance.
a Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research , University of South Australia , Adelaide , Australia.
Rebecca L
RL
Thomson
a Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research , University of South Australia , Adelaide , Australia.
Daniel K
DK
Rogers
b Clinical Nutrition Research Centre , University of Newcastle, Callaghan , New South Wales , Australia.
Peter R C
PR
Howe
a Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research , University of South Australia , Adelaide , Australia.
Jonathan D
JD
Buckley
D000328:Adult; D056352:Athletes; D054874:Athletic Performance; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005221:Fatigue; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D010807:Physical Endurance / Q000502:physiology
athletic performance; exercise onset; exercise-induced fatigue; heart rate kinetics; heart rate response