Did you know that if you sleep 5 or 6 hours a night or less you are at increasing risk of being overweight? Adults should be sleeping between 7 to 9 hours a night. Children on the other hand need at least 10 hours of sleep a night:
- A British study that followed more than 8,000 children found that those who slept fewer than 10 and a half hours a night at age 3 had a 45 percent higher risk of becoming obese by age 7, compared to children who slept more than 12 hours a night.
- The largest and longest study to date on adult sleep habits and weight is the Nurses’ Health Study. This study followed 68,000 middle-age American women for up to 16 years. Compared to women who slept seven hours a night, women who slept five hours or less were 15 percent more likely to become obese over the course of the study.
What is even more remarkable is that the impact of sleep loss with weight gain is more immediate than previously thought. A recent study at the University of Colorado shows that just a few nights of inadequate sleep can lead to an immediate weight gain of one to two pounds:
This study showed that just one week of restricted sleep of five hours per night leads to an average weight gain of two pounds within that week itself. Reverting to 9 hours of sleep per night the following week caused some of the weight gain to be shed, but significantly it did not reverse all the gain. This shows that some of the damage done by sleep loss may be long term and may take longer to reverse.
It is not clear what is the exact mechanism by which lack of sleep causes weight gain, but here are some findings from other studies:
- Lack of sleep changes our hormones: A small study has found that lack of sleep causes hunger-inducing hormones to increase. It also causes the satiety producing hormones to reduce. The net impact of this is that we tend to eat more when we are sleep deprived.
- Lack of sleep impacts our food choices: Studies have shown that those who slept less had consistently poor food habits. They ate food irregularly and snacked more often.
- There is a direct correlation between stress and weight. The more stressed we are, higher the likelihood that we may be overweight. Sleep is one of the best known de-stressor available to us. So it is likely that cutting down on sleep leads to increase in stress levels and a corresponding weight gain.
One way to increase the length and quality of sleep is to have a regular practice of yoga. If you add 10 minutes of breathing exercises (that elongates your breath) you will get even better results. 20 minutes of meditation every day will also help.
In some ways this is all good news. It shows that shedding weight for the long term is not so difficult after all. You are just required to regularly get adequate sleep. Can it get any easier?