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Sleep Patterns & Weight

Prior research has shown not getting enough sleep can impact your weight, but new research published online in the American Journal of Health Promotion, has shown the consistency of your bed time and wake time can also influence body fat.

The study of the sleep habits of more than 300 women found that those with the best sleeping habits had healthier weights. Specifically:

  • a consistent bed time and, especially, a consistent wake time are related to lower body fat;
  • getting less than 6.5 or more than 8.5 hours of sleep per night is associated with higher body fat; and
  • quality of sleep is important for body composition.

The most surprising finding from the study, according to the researchers, was the link between bed time and wake time consistency and body weight. Study participants who went to bed and woke up at, or around the same time each day had lower body fat. Those with more than 90 minutes of variation in sleep and wake time during the week had higher body fat than those with less than 60 minutes of variation.

Wake time was particularly linked to body fat: those who woke up at the same time each morning had lower body fat. The researchers concluded that staying up late and even sleeping in may be doing more harm than good. When sleep hygiene is altered, it can influence physical activity patterns and affect some of the hormones related to food consumption, thereby contributing to excess body fat.

The study found there was a sweet spot for amount of sleep: those who slept between 8 and 8.5 hours per night had the lowest body fat.

Sleep quality also proved to have a strong relationship to body fat. Sleep quality is a measure of how effective sleep is, or how much time spent in bed is spent sleeping. Those who had better sleep quality had lower body fat.

Factors which improve sleep quality include keeping the temperature in the bedroom cool, having a quiet room, having a dark room and using the bedroom only for sleeping.

Allen M et al., Objectively Measured Sleep Patterns in Young Adult Women and the Relationship to Adiposity. American Journal of Health Promotion, 2013; : 131107080257006 DOI: 10.4278/ajhp.121012-QUAN-500

Categories: Weight Management