Table 1.

Systemic hemodynamic responses

	1 ATA (21% O2)		2.82 ATA (7.4% O2)		2.82 ATA (100% O2)
	Rest	Exercise	Rest	Exercise	Rest	Exercise
Heart rate, beats/min	68 ± 1	68 ± 1	66 ± 1*	68 ± 1	66 ± 1*	66 ± 1*†
Mean arterial pressure, mmHg	86 ± 2	90 ± 2	91 ± 3*	94 ± 3*	92 ± 2*	98 ± 3*†
Cardiac output, l/min	5.8 ± 0.2	5.8 ± 0.2	5.9 ± 0.3	5.9 ± 0.2	5.8 ± 0.2	5.8 ± 0.2

Values are means ± SE.

^*P < 0.05 vs. 1 atmospheres absolute (ATA) at 21% O₂;

^†P < 0.05 vs. 2.82 ATA at 7.4% O₂.