Deep sleep is one of the pillars of health (see The Pillars of Health for the other three). In today’s world, almost no one gets enough sleep. Every sleep study ever done has proven that almost everyone requires at least 7-8 hours of sleep (many people require 9 hours) every night to function at their best. In addition, even mild sleep deprivation (say, sleeping 6 hours per night most nights) substantially increases your risk for heart disease, cancer, and a slew of other diseases. Further, sleep is the time when both body and brain repair themselves. Missing out on sleep thus leads to premature aging and significantly worse mood. Not only is getting enough sleep critical to optimum health; the quality of your sleep is important too. Sleeping irregular hours is never as restorative as sleeping in rhythm with the sun (see Stay Energized Naturally for more). In addition to a normal sleep schedule, healthy sleep requires stable blood sugar, a quiet, dark sleep environment, and a clear, open respiratory tract.


Sleeping Well Principles:

1. Deep Sleep Requires Stable Blood Sugar

If you've read through the rest of this site, we might sound a bit like a broken record constantly harping on the importance of stable blood sugar, but it really is one of the most profound variables affecting physical and mental performance. The way that blood sugar affects sleep is different from the way in which it affects energy, mood, and mental focus. When you’re awake, your brain needs a steady supply of sugar from your blood for you to stay alert and think clearly. When you’re asleep, maintaining stable blood sugar isn’t as critical to supporting the performance of your brain, but your brain still needs a steady flow of sugar to stay healthy. If blood sugar levels drop precipitously during sleep, your brain senses this and sends a distress signal to your body. Your body responds by liberating stored sugars from your liver. Critically, part of the way your body mobilizes these sugar stores is by releasing cortisol.

Cortisol is the same chemical your adrenal glands release to wake you up in the morning. Whenever it is released, cortisol invariably wakes the body up. Since cortisol always gets released in response to low blood sugar, blood sugar dips during the night inevitably result in disturbed sleep.  Even if you don’t actually wake up, blood sugar fluctuations during sleep can prevent you from sleeping deeply. If you’ve ever had the experience of sleeping through the night, but awakened feeling like you’d barely slept at all, there’s a decent chance that this was a result of cortisol surging through your body during the night in response to dips in blood sugar.

The best way to ensure stable blood sugar levels at night is to avoid eating within 2 to 3 hours before bed, and to make sure to eat a reasonably sized dinner that isn’t too difficult to digest (a huge meal or hard to digest foods will also keep you up simply because your body has to work so hard to process them). Avoid “high glycemic” carbohydrate foods at night, and base your dinners on combinations of vegetables (not carrots, leeks, parsnips, potatoes, or other root vegetables, which are high glycemic) with meats or low glycemic carbs like beans, wild rice, or quinoa. TAke a look at Controlling Appetite and Cravings for more on choosing low glycemic carbs.