Exercise improves recovery of ventilation in male asthmatic subjects in the steady state.
The effect of a three-minute exercise step test (submaximal) on the recovery of tidal volume (V(T)), respiratory frequency (f(R)) and minute ventilation (V(E)) has been investigated in non-asthmatic subjects, asthmatic subjects that exercise regularly and asthmatics that do not participate in regular exercise. Recovery was observed over twenty minutes at two-minute intervals. Ten male non-asthmatic subjects (NAS) (mean age 20.7+/- 0.4 yr), six male asthmatic subjects (20.5+/- 0.5 yr) that exercised regularly (EAS) and six male asthmatic subjects (20.8+/- 0.5 yr) that did not exercise regularly (NEAS) were studied. Exercise significantly increased all the measured variables in all the groups of subjects (P<0.001 in each case). At the end of the 20th minute, magnitude of recovery of V(T) was 123.3+/- 4.5% in NAS, 102.4+/- 5.1% in EAS (p<0.001) and 87.9+ 5.4% in NEAS (p<0.001). Mean rate of recovery of V(T) was highest (6.3%/min) in NAS and least in NEAS (4.4%/min). At the end of the (T)observation period, recovery of respiratory frequency (f(R)) was 100.0+/- 5.0% in NAS, 100.0+/- 4.5% in EAS and 89.2+/- 3.0 in NEAS. Mean rate of recovery of f(R) was 5.0%/min in NAS and EAS subjects respectively and 4.4%/min in NEAS subjects. Also, at the end of the 20th minute, the magnitude of recovery of V(E) was similar between NAS and EAS (105.1+/- 1.5% and 101.6+/- 1.75% respectively). Recovery of V(E) was significantly less in NEAS (93.9+/- 2.5%; p<0.01). Mean rate of recovery of V(E) was similar between NAS and EAS subjects (5.0%/min in each case) and 4.1%/min in the NEAS subjects. Thus regular exercise improves the recovery of ventilatory parameters in asthmatic subjects.
Jaja
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Department of Physiology, College of Medicine, University of Lagos, Lagos - Nigeria, PMB 12003.
Agidigbi
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D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D016022:Case-Control Studies; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D008297:Male; D012123:Pulmonary Ventilation / Q000502:physiology*; D013990:Tidal Volume / Q000502:physiology; D013997:Time Factors