Table 1.
Blood variable responses to whole body heat stress at rest and during exercise
| Control |
Skin Hyperthermia |
Skin and Mild Core Hyperthermia |
Skin and Core Hyperthermia |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Rest | Exercise | Rest | Exercise | Rest | Exercise | Rest | Exercise | ||
| Hb, g/l | a | 146 ± 3 | 152 ± 3 | 145 ± 3 | 150 ± 3 | 147 ± 3 | 151 ± 3 | 149 ± 3 | 152 ± 3 |
| v | 147 ± 3 | 156 ± 3 | 148 ± 3 | 152 ± 3 | 150 ± 3 | 153 ± 3 | 151 ± 3 | 153 ± 3 | |
| O2 Sat, % | a | 97.9 ± 0.2 | 97.9 ± 0.3 | 97.8 ± 0.2 | 98.1 ± 0.1 | 98.0 ± 0.3 | 98.0 ± 0.2 | 98.6 ± 0.2 | 98.3 ± 0.2 |
| v | 67.1 ± 3.5 | 32.3 ± 1.5 | 80.5 ± 1.5 | 37.0 ± 1.5 | 83.5 ± 1.6 | 41.8 ± 2 | 83.7 ± 1.7 | 46.1 ± 1.9 | |
| Po2, mmHg | a | 109 ± 4 | 107 ± 4 | 102 ± 3 | 110 ± 4 | 110 ± 5 | 110 ± 5 | 121 ± 5†# | 113 ± 5 |
| v | 38 ± 2 | 25 ± 1 | 48 ± 2 | 26 ± 1 | 50 ± 2* | 28 ± 1* | 48 ± 2* | 29 ± 1* | |
| CtO2, ml/l | a | 199 ± 5 | 209 ± 5 | 197 ± 5 | 204 ± 5 | 200 ± 7 | 206 ± 5 | 204 ± 6# | 207 ± 6 |
| v | 128 ± 8 | 65 ± 4 | 165 ± 3* | 75 ± 4 | 170 ± 5* | 87 ± 6* | 174 ± 7* | 99 ± 5* | |
| Pco2, mmHg | a | 39 ± 2 | 39 ± 2 | 39 ± 1 | 35 ± 1 | 32 ± 2* | 31 ± 3 | 25 ± 3* | 29 ± 3 |
| v | 49 ± 1 | 67 ± 2 | 42 ± 1* | 58 ± 3 | 36 ± 2*# | 50 ± 3 | 29 ± 3*†# | 43 ± 4 | |
| pH | a | 7.41 ± 0.02 | 7.40 ± 0.02 | 7.40 ± 0.01 | 7.43 ± 0.02 | 7.44 ± 0.02 | 7.45 ± 0.02 | 7.52 ± 0.03*# | 7.48 ± 0.03 |
| v | 7.37 ± 0.01 | 7.27 ± 0.01 | 7.40 ± 0.01* | 7.31 ± 0.02* | 7.43 ± 0.01*# | 7.37 ± 0.02*# | 7.50 ± 0.02*†# | 7.40 ± 0.03 | |
| Na+, mmol/l | a | 139 ± 1 | 142 ± 2 | 139 ± 1 | 142 ± 3 | 138 ± 2 | 140 ± 2 | 137 ± 2 | 139 ± 2 |
| v | 139 ± 2 | 143 ± 1 | 139 ± 2 | 142 ± 3 | 138 ± 1 | 141 ± 0 | 137 ± 2 | 139 ± 2 | |
| K+, mmol/l | a | 4.0 ± 0.1 | 4.6 ± 0.1 | 4.0 ± 0.1 | 4.4 ± 0.1 | 3.9 ± 0.1 | 4.1 ± 0.1 | 3.9 ± 0.1 | 4.0 ± 0.1 |
| v | 4.1 ± 0.1 | 4.9 ± 0.1 | 4.0 ± 0.1 | 4.7 ± 0.1 | 3.9 ± 0.1 | 4.3 ± 0.1 | 3.8 ± 0.1 | 4.1 ± 0.1 | |
| Cl−, mmol/l | a | 108 ± 3 | 108 ± 1 | 108 ± 1 | 108 ± 1 | 107 ± 1 | 108 ± 1 | 107 ± 1 | 105 ± 1 |
| v | 105 ± 2 | 105 ± 1 | 106 ± 1 | 104 ± 1 | 106 ± 1 | 104 ± 1 | 105 ± 1 | 104 ± 1 | |
| Glucose, mmol/l | a | 5.9 ± 0.2 | 5.8 ± 0.1 | 7.5 ± 0.3 | 7.2 ± 0.3 | 9.2 ± 0.5 | 8.2 ± 0.4 | 8.7 ± 0.5 | 7.9 ± 0.4 |
| v | 5.5 ± 0.2 | 5.7 ± 0.1 | 7.0 ± 0.3 | 7.0 ± 0.3 | 8.5 ± 0.4 | 7.8 ± 0.4 | 8.1 ± 0.5 | 7.5 ± 0.4 | |
| Lactate, mmol/l | a | 1.0 ± 0.1 | 2.7 ± 0.3 | 1.6 ± 0.2 | 2.6 ± 0.2 | 2.9 ± 0.3 | 3.3 ± 0.3 | 3.0 ± 0.3 | 3.7 ± 0.5 |
| v | 1.0 ± 0.1 | 4.1 ± 0.5 | 1.5 ± 0.1 | 3.4 ± 0.5 | 2.8 ± 0.3 | 3.8 ± 0.5 | 3.0 ± 0.3 | 4.1 ± 0.7 | |
| Osmolality , mOsm·kg−1 | a | 284 ± 2 | 289 ± 3 | 283 ± 2 | 288 ± 3 | 285 ± 2 | 286 ± 2 | 282 ± 3 | 285 ± 3 |
| v | 284 ± 2 | 291 ± 2 | 285 ± 3 | 291 ± 3 | 284 ± 2 | 289 ± 3 | 281 ± 2 | 285 ± 3 | |
| ATP, nmol/l | a | 454 ± 102 | 709 ± 158§ | 639 ± 120*§ | 842 ± 193§ | 704 ± 150§ | 950 ± 227§ | 917 ± 196§ | 1090 ± 200*†§ |
| v | 685 ± 80 | 867 ± 114 | 754 ± 42 | 851 ± 78 | 824 ± 115 | 903 ± 55 | 874 ± 155 | 822 ± 145 | |
| Noradrenaline, nmol/l | a | 0.7 ± 0.3 | 1.3 ± 0.4 | 0.6 ± 0.3 | 1.1 ± 0.3 | 1.5 ± 0.6 | 2.6 ± 0.5 | 2.0 ± 0.7* | 4.6 ± 1.4* |
| v | 0.8 ± 0.2 | 2.1 ± 1.3 | 0.7 ± 0.2 | 1.3 ± 0.3 | 1.3 ± 0.6 | 2.2 ± 1.0 | 2.0 ± 0.9* | 4.9 ± 2.4* | |
| Adrenaline, nmol/l | a | 1.1 ± 0.2 | 1.7 ± 0.3 | 0.8 ± 0.2 | 1.3 ± 0.2 | 0.8 ± 0.2 | 1.0 ± 0.1 | 0.7 ± 0.1 | 0.8 ± 0.2 |
| v | 0.4 ± 0.1 | 1.1 ± 0.2 | 0.7 ± 0.1 | 1.1 ± 0.1 | 0.7 ± 0.1 | 0.7 ± 0.1 | 0.6 ± 0.1 | 0.8 ± 0.1 | |
Values are means ± SE for 11 subjects, except for plasma ATP (a, n = 10 and v, n = 8), noradrenaline (n = 6), and adrenaline (n = 6). a, Arterial; v, femoral venous.
*
Different from control, P < 0.05;
#
different from skin hyperthermia, P < 0.05;
†
different from skin and mild core hyperthermia, P < 0.05. An additional one-way ANOVA with Tukeys honestly significant difference was performed on arterial plasma ATP values to determine any significant differences from control rest conditions (§P < 0.05).