'Arterial oxygen saturation during running, cycling and arm-cranking

Wood, R.J. and Morton, A.R., 'Arterial oxygen saturation during running, cycling and arm-cranking', Proceedings of the Sports Medicine Australia State Conference, 1995.

During exercise, arterial oxygen saturation (%SaO2) usually remains high. However in many elite endurance athletes, %SaO2 as been observed to decrease significantly during maximal exercise. Studies on cyclists have shown that a high VO2 is necessary for desaturation to occur. Although a relationship between %SaO2 and Ve/VO2 has also been suggested, not all studies have been able to consistently demonstrate this. Most studies on %SaO2 have been on cyclists; however both Ve and VO2 can vary with exercise mode. The purpose of this study was therefore to investigate the effect of exercise mode induced changes in Ve and VO2 on %SaO2.

Thirteen well-trained triathletes performed three continuous incremental maximal exercise tests on separate occasions and in a randomised order: one each of treadmill running (T), cycling (C) and aim-cranking (A). %SaO2 was recorded in duplicate each minute using pulse oximetry (Ohmeda Biox 3700e & Criticare US504). The results (ave ± sd) are presented below.

peak VO2 (ml.kg-1.min-1) * 68.6 ±5.4 65.3 ± 5.0 50.5 ± 4.3
peak Ve (l.min-1)^ 163.2 ± 22.5 166.9 ±21.1 140.8 ± 24.0
Ve/VO2* 27.2 ± 2.4 29.0 ±2.8 32.0 ± 4.2
min. ave-%Sa02 ** 91.0 ± 3.3 93.9 ± 1.9 95.7 ±2.0

*: A significantly different from T & C     **: T significantly different from A & C

The lowest %SaO2 was found for T, which corresponded to the highest VO2 and the lowest Ve/VO2. Within each exercise mode, %SaO2 did not correlate with any other variable. When data from all three exercise modes were combined, %SaO2 was significantly correlated with VO2 (r=-0.42, p<0.01) and Ve/VO2 (r=0.36, p<0.05).  Significant correlations were only found when all data were combined, probably due to achieving a greater range of scores. These combined results are similar to that found previously within groups exercising on a single exercise mode.

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