L. Cordain et al., RESIDUAL LUNG-VOLUME AND VENTILATORY MUSCLE STRENGTH CHANGES FOLLOWING MAXIMAL AND SUBMAXIMAL EXERCISE, International journal of sports medicine, 15(3), 1994, pp. 158-161
In order to evaluate a mechanism which may be responsible for the ofte
n observed acute increase in residual lung volume (RV) following exerc
ise, 12 non-smoking males (20-30yrs) performed two bouts of exercise o
n separate days; one to maximal heart rate (HRmax) and one to 85 % of
HRmax for 20 min. Prior to exercise and at 5, 15, 30, 60 and 120 min p
ost-exercise, the following parameters were measured: RV, forced vital
capacity (FVC), forced expiratory volume (FEV(1.0)), forced expirator
y flow (FEF(75-85)), maximal expiratory pressure (PEmax), and maximal
inspiratory pressure (PImax). Significant (p <0.05) increases occurred
in RV at 5, 15 and 30 min following maximal exercise and at 5 and 30
min after submaximal exercise. Changes in RV between the two exercise
bouts were generally greater (p < 0.05) for maximal exercise. Accompan
ying the increases in RV were significant (p < 0.05) decreases in PEma
x and decreases in FVC, while FEV(1.0) and FEF(75-85) remained general
ly unchanged or were slightly elevated. The data suggest that decrease
s in expiratory muscle strength due to fatigue may in part be responsi
ble for increases in RV.