Acute impairments in glucose tolerance following one night of partial sleep restriction are not rescued by moderate-intensity walking in young men

Background: High-intensity interval exercise ameliorates the impairment of postprandial metabolic health (e.g., glucose control) that is observed after a night of inadequate sleep. It is unknown whether moderate-intensity walking can elicit similar effects. Methods: Eleven healthy active males (age: 26 ± 2 yr; BMI: 22.8 ± 2.6 kg/m²) took part in a randomized and repeated-measures cross-over study with: (1) normal sleep (NS; 8 h sleep opportunity); (2) sleep restriction (SR; 3 h sleep opportunity); and (3) sleep restriction + exercise (SRE; 3 h sleep opportunity followed by 30 min brisk walking at 50%V̇O_2max). This was followed by a 2-h 75 g oral glucose tolerance test (OGTT), with plasma samples collected at baseline, immediately post-exercise (or sedentary), and at regular intervals during OGTT. Results: Total glucose area under the curve (tAUC) was lower in NS trial (924 [95%CI 865, 982] mmol/L) compared to both SR (1012 [95% CI 945, 1080] mmol/L, p = 0.018) and SRE trials (1006 [933, 1080] mmol/L, p = 0.002) and there was no difference between SR and SRE (p = 1.00). Insulin tAUC did not differ between trials (p = 0.472). There were no differences in fasting cortisol, c-reactive protein, and non-esterified fatty acids, and fasting and postprandial triacylglycerols, cholesterol, aspartate aminotransferase, and alanine aminotransferase concentrations between trials (all, p > 0.05). Conclusion: In healthy physically active young males, a single night of partial sleep restriction results in a decrease in glucose tolerance during a 2-h OGTT performed the following morning and this impaired response is not rescued by 30 min of brisk walking immediately prior to the OGTT.