How does sleep deprivation influence glucose tolerance?
In one study, after 1 week of sleeping 4 hours per night, there were increases in post-breakfast insulin resistance. During sleep restriction, glucose tolerance is nearly 40% worse compared with that in a group with sleep extension. Interestingly, it is first-phase insulin release that has been found to be markedly reduced. When sleep-deprived individuals go into recovery sleep (sleeping during the day because of prior sleep deprivation), there are marked elevations of glucose and insulin levels, indicating that sleep also exerts modulatory influences on glucose regulation independent of the circadian rhythm. At this point, it is important to reference a recent meta-analysis of 36 studies incorporating over 1 million patients, which compared the relative contribution of sleep disturbances risk for T2DM development with traditional T2DM risk factor development; the relative risk of T2DM development is given within parenthesis: overweight (2.99) > family history of T2DM (2.33) > personal history of OSA (2.02) > sleep less than 5 hours (1.48) > shift work or sleeping > 9 hours or the independent characteristic of poor sleep quality (1.4) > physical activity (1.2); this demonstrating traditional RF greater relative contribution than sleep characteristics, but sleep characteristics clearly important.