Table 2.
Hemoglobin (Hb), hematocrit (Hct), glucose, lactate, and plasma volume loss (Pvol loss), plasma osmolality (Posm), plasma free fatty acid (FFA), plasma epinephrine (EPI) concentration, and serum heat shock protein (Hsp) 72 content during 90 min of cycling at ∼65% VO2peak and at 50% (TT1) and 90% (TT2) of work completed in the time trial in the hydrated (HYD) and dehydrated (DEH) trials
| Trial | Time (min) | Time trial | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 20 | 40 | 60 | 75 | 90 | TT1 | TT2 | ||
| Hb | HYD | 13.9 ± 0.4 | 14.5 ± 0.4* | 14.5 ± 0.4* | 14.6 ± 0.4* | 14.7 ± 0.3* | 14.6 ± 0.2* | 14.7 ± 0.3* | 14.8 ± 0.4* |
| (g/100 m) | DEH | 13.9 ± 0.5 | 14.8 ± 0.5* | 14.8 ± 0.5* | 15.0 ± 0.3†* | 15.2 ± 0.5†* | 15.3 ± 0.4†* | 15.5 ± 0.4†* | 15.7 ± 0.3†* |
| Hct | HYD | 41.1 ± 0.8 | 42.2 ± 0.8† | 42.5 ± 0.7* | 42.2 ± 0.7* | 42.6 ± 0.7* | 42.7 ± 0.6* | 43.0 ± 0.6* | 42.9 ± 0.6* |
| (%) | DEH | 41.6 ± 0.8 | 42.7 ± 0.7* | 42.6 ± 0.7* | 42.5 ± 0.7* | 42.8 ± 0.7* | 42.9 ± 0.6* | 43.5 ± 0.6* | 43.7 ± 0.6* |
| Pvol loss | HYD | – | −3.6 ± 0.7* | −3.4 ± 0.9* | −3.9 ± 0.9* | −3.8 ± 1.2* | −4.9 ± 1.3* | −5.0 ± 0.9* | −5.2 ± 1.2* |
| (%) | DEH | – | −3.8 ± 0.9* | −4.1 ± 0.9* | −4.7 ± 1.4* | −5.3 ± 1.7*† | −7.7 ± 2.4*† | −8.0 ± 1.5*† | −11.4 ± 5.7*†‡ |
| Posm | HYD | 288 ± 1.5 | 290 ± 1.5 | 288 ± 1.1 | 287 ± 1.8* | 286 ± 1.6* | 286 ± 1.9* | 290 ± 1.7 | 293 ± 1.6* |
| (mOsmol/kg−1) | DEH | 290 ± 1.1 | 292 ± 1.0* | 293 ± 1.2*† | 293 ± 1.2*† | 294 ± 0.9*† | 296 ± 0.9*† | 301 ± 1.0*† | 300 ± 0.6*† |
| Glucose | HYD | 3.9 ± 0.3 | 3.9 ± 0.2 | 3.6 ± 0.1* | 3.6 ± 0.2* | 3.7 ± 0.1* | 3.7 ± 0.1* | 3.8 ± 0.2* | 3.7 ± 0.1* |
| (mmol/L) | DEH | 3.9 ± 0.1 | 4.0 ± 0.1 | 3.9 ± 0.1 | 3.9 ± 0.1 | 4.0 ± 0.1 | 3.7 ± 0.2* | 3.8 ± 0.1* | 3.8 ± 0.2* |
| Lactate | HYD | 0.9 ± 0.1 | 2.6 ± 0.4* | 2.5 ± 0.4* | 1.7 ± 0.3* | 2.0 ± 0.3* | 1.9 ± 0.3* | 8.0 ± 1.0* | 6.1 ± 1.4* |
| (mmol/L) | DEH | 0.9 ± 0.4 | 2.5 ± 0.4* | 3.1 ± 0.5*† | 2.6 ± 0.4*† | 2.5 ± 0.4*† | 2.6 ± 0.4*† | 7.8 ± 1.1* | 8.0 ± 0.8*† |
| Plasma FFA | HYD | 0.7 ± 0.03 | – | – | 0.7 ± 0.04 | – | 0.7 ± 0.1 | 0.6 ± 0.1 | 0.6 ± 0.1 |
| (mmol/L) | DEH | 0.7 ± 0.04 | – | – | 0.8 ± 0.03 | – | 0.8 ± 0.1 | 0.7 ± 0.1 | 0.7 ± 0.1 |
| Plasma EPI | HYD | 0.8 ± 0.1 | – | – | – | – | 1.1 ± 0.1* | 1.4 ± 0.2* | 2.1 ± 0.3*‡ |
| (nmol/L) | DEH | 0.7 ± 0.1 | – | – | – | – | 1.2 ± 0.1* | 1.6 ± 0.1* | 2.5 ± 0.3*‡ |
| Serum Hsp72 | HYD | 0.8 ± 0.2 | 0.9 ± 0.2 | – | 0.9 ± 0.2 | – | 0.9 ± 0.2 | 1.2 ± 0.3* | 1.3 ± 0.2* |
| (ng/mL) | DEH | 0.8 ± 0.1 | 0.9 ± 0.2 | – | 1.0 ± 0.3 | – | 1.1 ± 0.3 | 1.4 ± 0.4*† | 1.6 ± 0.3*† |
Data are mean ± SD (n = 9).
*
Significantly greater than 0 min (P < 0.05).
†
Significantly greater than HYD (P < 0.05).
‡
Significantly greater than TT 1 (P < 0.05).