Abstract
The effect of high altitude (HA) on exercise-induced diaphragm fatigue in normal subjects was examined. Eight normal subjects completed an incremental exercise test at sea level (SL) and at 3,325 m. Before (baseline), during, and after exercise (recovery), maximal transdiaphragm pressure (Pdi,sniff), breathing pattern, and diaphragmatic effort (PTPdi) were measured. Arterialized blood lactate was measured at baseline and during recovery. At maximal exercise (WRmax) Pdi,sniff fell to 72% and 61% of baseline at SL and HA respectively, recovering to baseline in 60 min at SL, and >60 min at HA. At the 5th min of recovery, circulating lactate was six-fold and seven-fold baseline at SL and HA, respectively. The time course of circulating lactate recovery was as for Pdi,sniff. At WRmax PTPdi was 80.74+/-9.87 kPa.s(-1) at SL and 64.13+/-8.21 kPa.s(-1) at HA. HA WRmax compared to isowork rate, SL data showed a lower Pdi,sniff (8.90+/-0.68 versus 11.24+/-0.59 kPa) and higher minute ventilation (117+/-11 versus 91+/-13 L.min(-1)), PTPdi being equal. To conclude, in normal subjects hypoxia-related effects, and not an increase in diaphragm work, hastens exercise-induced diaphragm fatigue and delays its recovery at high altitude compared to sea level.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
