Saturday, May 10, 2014

Feature Article: Are your sleeping habits affecting your weight?

There is strong evidence that sleep plays an important role in our health. Short sleep duration has been shown to increase risk of coronary heart disease (1), type 2 diabetes (2), hypertension (3), and even early death (4). It is now clear that we can add weight gain to this list.  

Why sleep deprivation is associated with weight gain is not yet understood. There are several hypotheses that are supported by the literature. In this feature article, we’ll take a look at some of the research and make some recommendations, so that you can be sure that your sleeping habits are bringing you closer to your weight loss goals and not further away.

Sleep And Weight Gain
The association between sleep and weight gain was examined in 68,183 women in Harvard’s Nurses’ Health Study (5). After 16 years of follow up, women who slept 5 hours per night had a 32% increased chance of gaining 15 or more kg (32 pounds) when compared to women sleeping 7 hours per night. Women sleeping 7-8 hours per night had the lowest risk of major weight gain.

Sleep And Subsequent Energy Intake
Thirty men and women were studied under both short sleep duration (4 hours per night) and habitual sleep (9 hours per night) for 5 nights (6). On the 5th day, they were given unlimited access to food and consumption was closely monitored. When subjects were sleep deprived, they consumed 295 more calories per day than when they had a full nights sleep.

Sleep And Metabolism
Fourteen normal weight males had their energy expenditure measured by indirect calorimetry on 2 separate occasions; after 8 hours of sleep and after complete sleep deprivation (7). When compared to a normal night’s sleep, energy expenditure was reduced by 5% following sleep deprivation.

Mechanisms Of Action
It is not entirely clear why sleep deprivation promotes weight gain. Several mechanisms have been supported by the research literature:

1) Sleep deprivation may alter neuronal pathways that regulate reward behaviors.

2) Sleep deprivation may increase levels of ghrelin, a hormone produced in the stomach which has been shown to increase hunger.

3) Sleep deprivation may decrease levels of leptin, a hormone which influences metabolism and satiety.

4) Fatigue resulting from sleep deprivation may reduce physical activity.

5) Sleep deprivation may decrease thermogenesis.

It is likely that several of these proposed mechanisms are working in concert.

Recommendations
I have my clients shoot for a minimum of 7 hours of sleep per night. Those that fall short do so for one of 2 reasons:

They are too busy to get a full night’s sleep. 
 
The answer to this is simply to make sleep a priority. Arrange your schedule to get to bed 7 hours before you need to wake up, no excuses. If you are watching a game or an awesome TV show, DVR it and watch the rest the next day.

They can’t fall or stay asleep.

This can be for a variety of reasons. Here are some potential solutions:

 1) Meditate for 10 minutes before you go to bed. This will get your body and mind prepared for sleep. To learn how to do this, pick up The Relaxation Response by Herbert Benson, MD.

2) White noise can be useful, particularly if you live in a city. We use an air purifier that drowns out extraneous noise 100%.

3) Make it really dark in your bedroom. Early morning light may be creeping in and waking you up. Really good blinds or a sleep mask takes care of this.

4) Don’t drink anything after 8:00 PM. Sometimes a midnight bathroom break disrupts your rhythm and then you can’t get back to sleep.

5) Limit caffeine, particularly in the late afternoon and early evening.

References
1) Ayas NT, et al. A prospective study of sleep duration and coronary heart disease in women. Archives of Internal Medicine 2003; 163 (2):205-209.

2) Ayas NT, et al. A prospective study of self-reported sleep duration and incident diabetes in women. Diabetes Care 2003; 26:380-84.

3) Tochikubo O, et al. Effects of insufficient sleep on blood pressure monitored by a new multibiomedical recorder. Hypertension 1996; 27:1318-24.

4) Wingard DL, et al. Mortality risk associated with sleeping patterns among adults. Sleep 1983; 6:102-07.

5) Patel SR, et al. Association between reduced sleep and weight gain in women. American Journal of Epidemiology 2006; 164:947-54.

6) St-Onge MP, et al. Short sleep duration increases energy intakes but does not change energy expenditure in normal weight individuals. American Journal of Clinical Nutrition 2011; 94:410-16.

7) Benedict C, et al. Acute sleep deprivation reduces energy expenditure in healthy men. American Journal of Clinical Nutrition 2011; 93:1229-36.

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