Gas exchange during maximal upper extremity exercise.
OBJECTIVE
to characterize gas exchange and cardiopulmonary performance during maximal progressive arm crank exercise.


METHODS
Cardiopulmonary variables were measured and arterial blood gases were determined in blood samples obtained from an indwelling radial arterial catheter during arm crank exercise (34 watts/min). Arm crank exercise was compared to maximal leg exercise performed by a different but comparable group of subjects from a previous study.


METHODS
19 healthy young (mean +/- SEM: 20 +/- 1 yr) black males.


RESULTS
Peak arm crank exercise resulted in lower values compared to peak leg exercise for: power (129 +/- 2 vs 253 +/- 10 W), VO2 (2.17 +/- 0.04 vs 3.26 +/- 0.14 L/min); VCO2 (2.9 +/- 0.11 vs 4.32 +/- 0.17 L/min); HR (168 +/- 3 vs 189 +/- 3 beats/min); AT (1.15 +/- 0.05 vs 1.83 +/- 0.07 L/min); and VE (101 +/- 2 vs 144 +/- 8 L/min), respectively. Arm crank exercise (baseline vs peak) elicited an impressive improvement in PaO2 (85 +/- 1 to 97 +/- 1 mm Hg), no change in SaO2 (96 +/- 0.2 to 96 +/- 0.2 percent), no significant increase in P(A-a)O2 (3 +/- 0.7 to 5 +/- 0.9 mm Hg) and an appropriate trending decrease in VD/VT (0.22 +/- 0.01 to 0.17 +/- 0.01). Peak arm crank values were significantly different from peak cycle exercise for PaO2 (82 +/- 2.2 mm Hg), SaO2 (93 +/- 0.4 percent), P(A-a)O2 (21 +/- 1.9 mm Hg) and VD/VT (0.08 +/- 0.01). At comparable levels of VO2 for arm crank and cycle exercise (2.17 +/- 0.04 vs 2.26 +/- 0.08 L/min), significant differences were observed for PaO2 (97 +/- 1.4 vs 81 +/- 1.9 mm Hg); SaO2 (96 +/- 0.2 vs 94 +/- 0.4 percent); P(A-a)O2 (5 +/- 0.9 vs 14 +/- 1.5 mm Hg); and VD/VT (0.17 +/- 0.01 vs 0.08 +/- 0.01), respectively.


CONCLUSIONS
Maximal arm crank exercise represents a submaximal cardiopulmonary stress compared to maximal leg exercise. The differences in gas exchange observed at peak exercise between arm crank and leg exercise for the most part reflect the lower VO2 achieved. However, the persistence of these gas exchange differences even at a comparable level of VO2 suggests that factors other than VO2 may be operative. These factors may include differences in alveolar ventilation, CO2 production, ventilation-perfusion inequality, diffusion, and control of breathing.
Martin
T W
TW
Department of Clinical Investigation, William Beaumont Army Medical Center, El Paso, TX.
Zeballos
R J
RJ
Weisman
I M
IM
D000328:Adult; D015308:Anaerobic Threshold; D001132:Arm; D006339:Heart Rate; D006801:Humans; D008297:Male; D005082:Physical Exertion; D011659:Pulmonary Gas Exchange