Table 2.
Effect of head-down tilt bed rest (HDBR) on 24-h rectal temperature rhythm.
| Parameter | Group | HDBR7 | HDBR49 |
|---|---|---|---|
| Mesor (°C) | CTR | 36.86 ± 0.05 | 36.83 ± 0.06 |
| RE | 36.78 ± 0.03 | 36.75 ± 0.02 | |
| RVE | 36.95 ± 0.05 | 36.87 ± 0.03 | |
| Amplitude (°C) | CTR | 0.48 ± 0.04 | 0.49 ± 0.03 |
| RE | 0.44 ± 0.07 | 0.46 ± 0.04 | |
| RVE | 0.46 ± 0.04 | 0.44 ± 0.04 | |
| Acrophase (h) | CTR | 16.95 ± 0.53 | 17.65 ± 0.49 |
| RE | 17.05 ± 0.32 | 16.60 ± 0.55 | |
| RVE | 17.52 ± 0.26 | 17.07 ± 0.43 |
Data are means and standard errors. Circadian parameters were determined by cosinor analysis using 24-h core body temperature recordings. Data were collected on day 7 (HDBR7) and day 49 (HDBR49) of HDBR. CTR performed HDBR only (n = 5). RE performed HDBR plus three times per week high-load resistive exercise (n = 5). RVE performed HDBR and the same exercise as the RE group, but with additional superimposed whole-body vibrations (n = 6).