Gas Exchange

In conclusion, maximal arm crank exercise resulted in an impressive improvement in P&02 (85 to 97 mm Hg) with no significant changes in Sa02 and P(A-a)02 (3 to 5 mm Hg) and an appropriate trending decrease in Vd/Vt (0.22 to 0.17). Compared to cycle exercise, arm crank exercise elicited a higher Pa02, Sa02, Vd/Vt, and […]

At comparable levels of Vo2 and power, PaC02 was identical for arm and leg exercise despite a greater minute ventilation and respiratory frequency and similar tidal volumes for arm crank vs lower extremity exercise; this was probably due to the increased Vco2 (Table 2). Also, it is possible that control of breathing during arm exercise […]

However, their blood samples were obtained after exercise from free-flowing digit punctures. Although such samples may be representative of arterial blood during lower extremity exercise, the technique may not be valid for upper extremity exercise or for comparing acid-base status during upper and lower extremity exercise. It is possible that arm crank exercise has a […]

Another possible explanation for the large difference between P(A-a)02 responses is that diffusion does not limit 02 exchange during maximal arm crank, but may, as has been suggested by Dempsey et al, limit exchange during exhaustive lower extremity exercise. Wagner and associates began to appreciate a diffusion component to the P(A-a)02 during leg exercise performed […]

The most important of these factors include ventilation-perfusion (V/Q) inequality and diffusion limitation. The increase in Pa02 during arm crank exercise was associated with a nonsignificant widening of the P(A-a)Os (Table 4); this suggests an overall minimal effect on ventilation-perfusion matching in the lungs at this level of submaximal cardiopulmonary stress. Better perfusion of the […]

The determinants for PkOs include those factors which affect the Pa02 and/or the P(A-a)02. At peak exercise, similar values for PaO£ flable 3) would suggest that factor(s) which affect the P(A-a)02 magnitude difference between arm crank and cycle exercise (5 mm Hg vs 21 mm Hg, respectively) must be responsible for the observed Pa02 differences. […]

Their subjects were slightly older (27 ±1.2 years) than ours (Table 1) and the power increments utilized were smaller (15 W/min); however, it is not likely that these differences would have had a significant effect on gas exchange. False arterial desaturation using the ear oximeter has been reported in subjects with a cardiovascular limitation to […]

Sawka has reviewed several studies which have compared the cardiopulmonary response to maximal arm crank and cycle exercise in untrained subjects. With the exception of peak heart rate, the differences measured in the present study are comparable to studies which had used the same subjects for both arm crank and cycle exercise. The lower heart […]

In this study, we characterized gas exchange responses to progressive arm crank exercise in untrained healthy young subjects in order to help define the normal pattern(s) of response based on direct measurement of arterial blood gases. Arm crank results have been referenced to lower extremity exercise values extracted from a previous study since an extensive […]

Gas Exchange Data Mean (± SEM) values for arterial blood gases during progressive arm crank exercise are shown in Table 4. The Pa02 significantly increased (p<0.05) in all subjects during arm crank exercise (range 1 to 20 mm Hg) while arterial oxygen saturation remained stable or increased (NS, p>0.05). The PaC02 decreased slightly in most […]