Effects of acute exercise on inspiratory muscle strength and endurance in untrained women and men.
OBJECTIVE
The purpose of this study was to determine if sex differences are present in exercise-induced inspiratory muscle function in untrained humans.


METHODS
Eight young untrained women (23.8 ± 1.5 y, VO2max = 33.7 ± 4.0 mL/kg/min) and men (26.1 ± 2.0 y, VO2max = 36.7 ± 1.2 mL/kg/min) performed high-intensity cycling exercise (80% WRmax) to exhaustion. Inspiratory muscle strength and endurance were assessed pre- and post-exercise by measuring maximal inspiratory pressure (PImax) and time to task failure during a constant-load breathing test (CLBT), respectively.


RESULTS
Relative intensity and time to exhaustion during high-intensity exercise was similar between women and men. Prior to exercise, PImax was similar between sexes. After exercise, women and men showed similar reductions in PImax (W: 140.4 ± 9.9 to 124.6 ± 6.7 cm H2O, P<0.05; M: 147.7 ± 10.2 to 128.1 ± 11.1 cm H2O, P<0.05). No sex difference was found in the magnitude change in PImax following exercise (W: 15.8 ± 7.9 vs. M: 19.6 ± 4.7 cm H2O). Time to task failure on the CLBT was reduced following exercise in women (360 ± 54 to 135 ± 29 s, P<0.05) and men (270 ± 36 to 150 ± 17 s, P<0.05). Women exhibited a greater reduction in time to task failure following exercise than men (W: 225 ± 55 vs. M: 120 ± 38 s, P=0.05).


CONCLUSIONS
These data demonstrate that women exhibit a greater reduction in inspiratory muscle endurance following an acute bout of high-intensity exercise than men.
Gonzales
J U
JU
Texas Tech University, Lubbock, TX, USA. jw88@txstate.edu
Williams
J S
JS
D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000502:physiology*; D012737:Sex Factors; D014939:Work of Breathing