Table 1 Resting cardiovascular and metabolic responses to acute physiological stressors

VO₂ (L · min^-1 STPD)

69 ± 10

65 ± 10

64 ± 10

 Normoxia

0.32 ± 0.08

0.30 ± 0.07

71 ± 14

73 ± 12*

75 ± 13*

 Heat

0.31 ± 0.07

0.32 ± 0.10

63 ± 9

69 ± 7

74 ± 8

 Hypoxia

0.33 ± 0.06

0.35 ± 0.07

68 ± 9

80 ± 12*

82 ± 10*

 Combined

0.34 ± 0.07

0.33 ± 0.08

Cardiac output (L · min^-1 STPD)

98 ± 1

97 ± 1

97 ± 2

 Normoxia

5.6 ± 1.3

5.4 ± 0.8

98 ± 1

97 ± 1

97 ± 1

 Heat

5.6 ± 1.0

5.9 ± 1.6

98 ± 1

90 ± 2*

89 ± 3*

 Hypoxia

5.4 ± 1.1

5.7 ± 1.0

97 ± 1

91 ± 2*

89 ± 3*

 Combined

5.5 ± 1.3

5.7 ± 1.6

Stroke volume (mL · beat^-1)

-

13.8 ± 4.4

13.3 ± 2.8

 Normoxia

87 ± 18

86 ± 13

-

13.8 ± 3.7

14.4 ± 4.7

 Heat

78 ± 12

79 ± 24

-

15.0 ± 4.3*

14.5 ± 3.6

 Hypoxia

80 ± 18

78 ± 19

-

13.7 ± 2.9

13.1 ± 2.8

 Combined

70 ± 15

68 ± 16

${\mathrm{a}‒\overline{\mathrm{v}}\mathrm{O}}_2$ difference (mL · L^-1)

-

11.3 ± 3.6

10.8 ± 2.2

 Normoxia

6.8 ± 0.5

6.8 ± 0.2

-

11.3 ± 3.0

11.7 ± 3.8

 Heat

6.9 ± 0.2

6.9 ± 0.3

-

12.7 ± 4.8

12.7 ± 3.9

 Hypoxia

6.8 ± 0.3

6.9 ± 0.4

-

11.5 ± 2.7

11.0 ± 2.7

 Combined

6.8 ± 0.2

6.9 ± 0.3

RER

-

0.39 ± 0.11

0.37 ± 0.06

 Normoxia

0.83 ± 0.07

0.82 ± 0.15

-

0.39 ± 0.07

0.41 ± 0.12

 Heat

0.79 ± 0.10

0.79 ± 0.10

-

0.37 ± 0.08

0.39 ± 0.08

 Hypoxia

0.90 ± 0.09*

0.88 ± 0.07*

-

0.38 ± 0.10

0.39 ± 0.13

 Combined

0.89 ± 0.08

0.85 ± 0.09