Half dozen healthy non-smoking SL citizen victims (two female, five guys; Table step 1) provided authored told say yes to be involved in the study. The brand new methods and you does airg work may protocols were authorized by the Federal Browse Council (CNR, Italy) as part of the Ev-K2-CNR search program and was basically presented in accordance with the Declaration out-of Helsinki.
Standards
Into the date step 1, this new victims did fundamental pulmonary setting assessment and you may got acquainted that have this new maximum progressive exercise decide to try. For the then date, the fresh new official maximum incremental get it done decide to try is actually conducted up to fatigue.
The HA phase of the study was conducted at the CNR Pyramid Laboratory, Lobuche, Khumbu, Nepal (5,050 m, barometric pressure approximately 410 Torr). After travelling by plane through Kathmandu (1,340 m) up to Lukla (2,860 m), all subjects performed a 10-day trek to the Pyramid Laboratory with the following intermediate stops for acclimatization: 3 days at Namche Bazaar (3,450 m) and then 2 days at Pheriche (4,252 m). Symptoms of acute mountain sickness and resting arterial O2 saturation (SpO2) were monitored. After 1 day of rest at the Pyramid Laboratory, the experimental phase started. On day 2, the subjects performed standard pulmonary function tests. Calibration of the spirometer (photoelectric digital turbine, diameter 28 mm, resolution 4 ml, Micro Kit, COSMED, Rome, Italy) was performed prior to each test, using a 3-l syringe.
Progressive do so test
On day 3, each subject performed a maximal incremental exercise test on a cycle ergometer. The pedaling frequency was set at 60 ± 5 rpm by subjects following an electronic audio signal generated each second. The test protocol consisted (a) 2 min of rest, (b) 4 min of exercise at 20 W, (c) the incremental phase with work rate increments of 15 W/min at HA and 25 W/min at SL, (d) 6 min of recovery pedalling at 20 W. O2 uptake ( V ? O 2 , standard temperature and pressure, dry (STPD)), CO2 output ( V ? CO 2 , STPD), minute ventilation ( V ? E , body temperature and pressure saturated BTPS), and end-tidal partial pressures for O2 and CO2 (PMais aussiO2, PAinsi queCO2) were obtained breath-by-breath and edited to exclude occasional outlying breaths (>±4 SD of the local mean) as a result of coughs, swallows, sighing, or gasping. A 10-s average was utilized for subsequent analysis.
For VCP estimation by analysis of the ? V ? E / ?HR relationship ( VCP V ? E / HR ), we utilized a least squares regression analysis. Using a dedicated software, we applied a ‘best fit’ line to the data which extended from end-exercise back to the sub-maximal point at which the linearity was lost (S2 region); this breakpoint was compared with the standard approach for VCP estimation ( VCP V ? E / V ? CO 2 ) based on the V ? E / V ? CO 2 relationship, where V ? E started to change out of proportion of V ? CO 2 and PAinsi queCO2 started to fall . From the aforementioned breakpoint, a second best fit line (S1) was applied to the data extending from the end of the warm-up phase upwards into the exercise data. If a second breakpoint was discernible, the S1 line was then divided in two different regions (S1” from the breakpoint to VCP V ? E / HR and S1‘ from the end of warm-up up to the observed breakpoint), and the HR value at this breakpoint was then compared with the value observed at lactate threshold (?L, estimated by the ‘V-slope method’ and supported by standard ventilatory equivalent and end-tidal gas tension criteria ).
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