Table 1.
Changes in blood volumes, plasma osmolality, and body mass throughout experimentation.
| Rest | Baseline | 60 min | End | ||
|---|---|---|---|---|---|
| CON | Δ Blood volume (%) | – | −1.7 ± 1.3 a | −2.3 ± 1.8 ab | −6.1 ± 2.9 ab |
| Δ Cell volume (%) | – | 0.5 ± 2.2 | −0.2 ± 2.0 | −0.7 ± 3.4 | |
| Δ Plasma volume (%) | – | −3.4 ± 2.0 a | −4.1 ± 3.0 ab | −10.4 ± 3.4 ab | |
| Plasma osmolality (mOsm kg−1) | 296 ± 5 | 293 ± 5 | 295 ± 3 | 297 ± 4 | |
| Δ Body mass (kg) | – | −0.3 ± 0.5 a | – | −1.1 ± 0.3 | |
| Δ Body mass (%) | – | −0.4 ± 0.6 a | – | −1.4 ± 0.4 | |
| DEH | Δ Blood volume (%) | – | −8.1 ± 2.5 ac | −9.0 ± 3.5 ac | −11.8 ± 2.8 ac |
| Δ Cell volume (%) | – | −0.5 ± 2.1 | −1.3 ± 1.5 | −1.8 ± 2.1 | |
| Δ Plasma volume (%) | – | −14.2 ± 5.7 ac | −15.3 ± 6.8 ac | −19.7 ± 5.1 ac | |
| Plasma osmolality (mOsm kg−1) | 293 ± 5 | 293 ± 4 | 296 ± 7 | 298 ±5 | |
| Δ Body mass (kg) | – | −2.0 ± 0.6 ac | – | −0.9 ± 0.4 | |
| Δ Body mass (%) | – | −2.4 ± 0.7 ac | – | −1.1 ± 0.6 | |
| SAL | Δ Blood volume (%) | – | −0.7 ± 2.6 c | 1.2 ± 3.4 bc | −1.6 ± 3.1bc |
| Δ Cell volume (%) | – | 0.6 ± 1.9 | 0.8 ± 2.2 | −0.3 ± 1.7 | |
| Δ Plasma volume (%) | – | −1.6 ± 5.0 c | 1.5 ± 6.8 bc | −2.7 ± 5.3 bc | |
| Plasma osmolality (mOsm kg−1) | 294 ± 4 | 290 ± 2 | 294 ± 5 | 296 ± 5 | |
| Δ Body mass (kg) | – | −0.4 ± 0.4 c | – | −1.1 ± 0.3 | |
| Δ Body mass (%) | – | −0.5 ± 0.5 c | – | −1.3 ± 0.4 |
Data are mean ± SD for seven subjects. CON, control condition without treatment; DEH, diuretic-induced dehydration; SAL, continuous saline infusion. Note: changes in blood, cell, and plasma volumes are expressed as percentage changes from rest; changes in body mass are expressed as absolute and percentage changes from rest to baseline (i.e. from arrival until the start of the incremental humidity protocol, “Baseline”) and from baseline to the end of the incremental humidity protocol (“End”).
a, b, and c indicate differences between CON and DEH, CON and SAL, and DEH and SAL, respectively (P < 0.05).