Altered Energy Balance in Response to Sleep Restriction

摘要

Many epidemiological studies suggest that short sleep duration leads to weight and fat mass gains over time. Sleep restriction (5.5 hours of sleep/night) has also been shown to alter weight loss success, by promoting a greater loss of fat-free mass coupled with a decrease in fat mass loss when compared to individuals who received 8.5 hours of sleep per night. Current evidence suggests that sleep restriction may lead to increased food intake but does not appear to result in decreased energy expenditure. Sleep restriction coupled with clamped energy intake has been suggested to alter the neuroendocrine regulation of appetite, through increases in the levels of ghrelin, combined with decreases in leptin. However, these variations may be subdued by an adequate access to food. Current evidence also suggests that sleep restriction leads to decreases in insulin sensitivity and acute insulin responses to glucose. Conversely, shortsleepers have glucose responses that are similar to averagesleepers, but at the cost of an increase in insulin release, which may be the result of decreased insulin sensitivity over time. Recent studies also provide evidence that sleep restriction enhances susceptibility to food stimuli, especially for energy-dense, high-carbohydrate foods. Furthermore, reduced sleep quality, defined as decreases in slow-wave sleep, has been suggested to alter proper neuroendocrine functions. However, these alterations only seem to occur following total sleep deprivation since slow-wave sleep is usually preserved during partial sleep restriction. In summary, current evidence suggests that the severity (number of hours per night) and duration (number of days) of sleep restriction are likely important factors in determining the extent of metabolic and non-homeostatic changes that may alter energy balance.