The effects of supplemental O2 on recovery from supramaximal exercise and subsequent performance remain unknown. If recovery from exercise could be enhanced in individuals with chronic lung disease, subsequent supramaximal exercise performance could also be improved. Recovery from supramaximal exercise and subsequent supramaximal exercise performance were assessed after 10 min of breathing 100% O2 or room air (RA) in 17 cystic fibrosis (CF) patients (25 +/- 10 (SD) yr old, 53% men, forced expired volume in 1 s = 62 +/- 21% predicted) and 17 normal subjects (25 +/- 8 yr old, 59% men, forced expired volume in 1 s = 112 +/- 15% predicted). Supramaximal performance was assessed as the work of sustained bicycling at a load of 130% of the maximum load achieved during a graded maximal exercise. Peak minute ventilation (VE) and heart rate (HR) were lower in CF patients at the end of each supramaximal bout than in controls. In CF patients, single-exponential time decay constants indicated faster recovery of HR (tau HR 86 +/- 8 and 73 +/- 6 s in RA and O2, respectively, p < 0.01). Similarly, fast and slow time constants of two-exponential equations providing the best fit for ventilatory recovery were improved in CF patients during O2 breathing (tau 1VE 132.1 +/- 10.5 versus 82.5 +/- 10.4 s; tau 2VE 880.3 +/- 300.1 versus 368.6 +/- 107.1 s, p < 0.01). However, no such improvements occurred in controls. Supramaximal performance after O2 improved in CF patients (109 +/- 6% of the 1st bout after O2 versus 94 +/- 6% in RA, p < 0.01). O2 supplementation had no effect on subsequent performance in controls (97 +/- 3% in O2 versus 93 +/- 3% in RA). We conclude that supplemental O2 after a short bout of supramaximal exercise accelerates recovery and preserves subsequent supramaximal performance in patients with CF.

Full text (sometimes free) may be available at these link(s):      help

• DOI
• PubMed
• PDF locator
• publisher