Table 2.
Ground and inflight nutrition and substrate oxidation data of the 11 astronauts
| Ground | Inflight | Changes from ground1 | ||
|---|---|---|---|---|
| LSmeans (SE) | LSmeans (SE) | LSmeans (95% CI) | P value | |
| Fasting state3 | ||||
| Energy expenditure (kJ.min−1)2 | 4.73 (0.20) | 4.58 (0.21) | −0.16 (−0.48 to 0.16) | 0.30 |
| Carbohydrate oxidation (g.min−1)2 | 0.13 (0.02) | 0.18 (0.02) | 0.06 (0.00–0.11) | 0.04 |
| Lipid oxidation (g min−1)2 | 0.04 (0.01) | 0.01 (0.01) | −0.03 (−0.05 to −0.01) | <0.01 |
| Respiratory quotient (RQ) | 0.85 (0.02) | 0.91 (0.02) | 0.07 (0.02–0.12) | <0.01 |
| Carbohydrate oxidation (%) | 44 (5) | 65 (5) | 21 (6–36) | 0.01 |
| Lipid oxidation (%) | 34 (6) | 10 (3) | −23 (−37 to −9) | <0.01 |
| Protein oxidation (%) | 22 (1) | 24 (1) | 2 (0–4) | 0.02 |
| Post-breakfast challenge (iAUC over 260 min)3 | ||||
| Energy expenditure iAUC (kJ)2 | 302 (29) | 452 (45) | 150 (36–264) | 0.01 |
| Carbohydrate oxidation iAUC (g)2 | 16.8 (6.4) | 22.3 (2.5) | 5.5 (−9.5 to 20.5) | 0.44 |
| Lipid oxidation iAUC (g)2 | 0.1 (2.3) | 3.1 (0.8) | 2.1 (−3.3 to 7.5) | 0.41 |
| ΔRQ | 0.06 (0.02) | 0.05 (0.02) | −0.02 (−0.07 to 0.04) | 0.56 |
| Diet4 | ||||
| Food quotient (FQ) | 0.84 (0.00) | 0.87 (0.00) | 0.03 (0.01 to 0.04) | <0.001 |
iAUC incremental area under the curve over the 260 min period of measurement, FFM fat-free mass, FM fat mass, ΔRQ maximal postprandial RQ–fasting RQ
1Estimated LSmeans (95% CI) and P value from mixed-effects models accounting for repeated values.
2Models for energy expenditure and absolute carbohydrate and lipid oxidation rates are adjusted for FFM and FM.
3Inflight data from 10 subjects
4Ground data from 7 subjects.