How Sleep Deprivation Affects Your Metabolism

Sleep is Important for Your Metabolism

It might not be a shock to hear this, as the importance of sleep has been in the news more frequently, but proper sleep is important for your metabolism. Short sleep makes it harder for you to lose weight, and can increase insulin resistance and cause glucose levels to rise. This week I'll highlight two hormonal changes that occur when you don't get enough sleep - increases in ghrelin and decreases in leptin.

Ghrelin and Leptin

Ghrelin and leptin are two hormones discovered since 1994 which have important effects on metabolism. For our discussion, think of leptin as a hormone that signals when you have sufficient energy - caloric intake and fat stores - and works to decrease appetite. Ghrelin is a hormone secreted by the stomach and is known to increase hunger.

In a classic study, researchers studied 12 healthy young men, and found that when they slept 4 hours nightly for 2 nights, compared with sleeping 10 hours, they had decreased levels of leptin and increased ghrelin. That is, the "I'm full" hormone decreased and the "I'm hungry" hormone increased. The subjects reported increased appetite, especially for high-carbohydrate foods, as outlined in this graph:

Limited sleep is also known to cause insulin resistance and higher glucose levels, and promotes the inability to lose fat during calorie restriction. An overall picture of sleep loss and its effect on metabolism could be modeled like this:

These underline the importance of good sleep when pursuing a healthy metabolism.

A Quick Note About Cognition

Slightly off the topic of metabolism, I thought you might be interested in this study about sleep and cognitive power. I'm pretty sure you want your brain power to be at its best. In this study, researchers found that 2 weeks of sleeping 6 hours per night produced deficits in cognition or thinking that were equivalent to those seen after 2 nights of sleeping zero hours! If you think you are functioning well on 6 hours of sleep of less per day, chances are you really aren't. Getting more sleep can help you to be more productive in a shorter amount of time.

Conclusion

How much sleep do you need? Most studies would suggest 7 to 7.5 hours is a good minimum target. If you're not getting this much, here are a few tips:

• Prioritize sleep. Make sure to leave enough time at night to wind down, put away all your screens, and prepare your body and mind for sleep.
• Keep a sleep schedule. Going to bed and getting up at roughly the same time each day makes it easier for your body to stay on track with sleep.
• Avoid alcohol or exercise too close to bedtime. Exercise is great, just not when you are getting ready to crawl between the sheets.
• Kick the TV out of the bedroom. Sleep experts say the bed should be reserved for sleep and intimacy. Finish your TV watching before you get into bed to help your body properly prepare for sleep.
• Get a diagnosis. If you have loud snoring or your partner tells you that you stop breathing at night, you might have a condition called sleep apnea. Check your risk here. And if your legs are jumping all around the bed, you could have restless legs syndrome. Talk with your doctor if you suspect a sleep disorder, as treatment might help your metabolism.

This week

Does your sleep need attention? If so, what is your plan this week to help your sleep? Sweet dreams!

Cheers,

Dr. Topher Fox