by Mark Sisson Mark's Daily Apple
Sleep is the cousin of death, wise men have said. Strange thought it may seem, though, avoiding this sometimes annoyingly-insistent-that-you-hang-out cousin will actually bring you closer to an early death. It’s not a pleasant thing to consider, but it’s the truth; bad sleep is associated strongly with early mortality, being overweight, having metabolic syndrome, and getting cancer. I’ve said it, your doctor says it, and anyone who’s ever had a bad night’s sleep and felt like death the next day will say it: sleep is absolutely essential to happiness, health, and longevity. On the positive side, there’s nothing quite so pleasurable as a good night’s sleep, from the initial application of one’s head to the pillow, to the insanely vivid dream-visions that descend upon you in the midst of it, to the peerless happiness and boundless energy you feel upon waking. Sleep’s the best, so you want to get it, and get it good.
You know it, of course. I harp on it enough. And chances are, you’re doing your part to get good sleep. But what if you can’t? What if sleep is bad, or inadequate, or unfulfilling? What might be causing it? Let’s find out.
You’re not getting any light during the day.
If you’ve read what I’ve written about blue light and sleep, you’re likely a champ with regards to blue light avoidance after dark. You’ve got the orange goggles. You’ve installed F.lux on all your computers (and you even jailbroke your iPhone to make it work there, too). You’ve set up black-out shades in your bedroom, and you’ve ditched the alarm clock with its blinking disruptive lights in favor of a personal rooster. And yet you still can’t get to sleep… what gives? Well, just as avoiding blue light after dark is important for normalizing your circadian rhythms and getting to sleep, exposing yourself to light during the day is also essential. Light’s entrainment capabilities go both ways. The whole problem with light at night is that it’s tricking your body into thinking it’s daytime. When it’s actually daytime, however, you need light. The whole daylong circadian cycle is important for sleep — not just the small snapshot taken right before bed. Try to get some sunlight on your eyes throughout the day, beginning (ideally) with the early morning. Right after you wake, go outside and take in the sun. Drink your coffee outside, or at least at a window facing the sun. At work, go outdoors for your breaks. Don’t say shut-in if you can help it.
You’re eating too late.
Remember the “early bird gets the worm”? The bird doesn’t have an actual alarm clock (trees don’t have power sources, duh!). By eating early in the morning, it has entrained its circadian rhythm to trigger early waking so as to obtain said food. This doesn’t just happen in birds, either. Rodent and primate studies show that feeding time is a powerful entrainer of the circadian rhythm, probably across species lines. In humans, the presence of C-peptide, which shows up after food intake and helps insulin do its job, strongly correlates with lower levels of melatonin. This suggests that eating depresses melatonin, the sleep hormone necessary for getting us ready to sleep. Couple that potential mechanism with the epidemiology of nocturnal eating being associated with negative effects on sleep quality, and you get a sneaking suspicion that eating late at night might be affecting some people’s ability to get a good night’s sleep.
You’re hewing to the popular advice to “stop eating carbs after 6 PM!”
Anytime I find myself thumbing through a Men’s Health or Shape or any other bad mainstream health and fitness magazine, I seem to stumble across this rule: no carbs after 6 PM. They’re usually imploring you to take this step in order to facilitate fat loss (which is false in and of itself), rather than to improve sleep quality. I’m all for the reduction in unnecessary carbohydrate from our diets, but if you’re going to eat carbs, sleep research indicates there’s absolutely no need to avoid them after dark or even right before bed. Heck, they can even be fast-digesting carbs, as one recent study showed that carbs with a higher glycemic index shortened sleep onset at night (people who ate the fastest-digesting carbs fell asleep faster than the people who ate the slow digesting carbs). So, if you’ve been avoiding all carbs after dark and eating them in the morning (to “provide energy”), you have probably been doing your sleep a disservice. If you’re gonna eat carbs, eat them at night. You should probably stop reading bad mainstream fitness magazines, too.
You’re exercising right before bed and failing to give yourself time to recover.
At night, your body reduces its temperature, and this drop in body temperature has been referred to as a physiological initiation of sleep onset and facilitator of entrance into the deeper phases. Since exercise raises body temperature, one wonders whether it could affect your sleep. In one study, researchers examined the effects of exercise on sleep with and without body cooling. Subjects ran for 40 minutes at 75% of their V02max on two occasions. The first time, the ambient temperature was raised, prompting a 2.3 degree C increase in subjects’ rectal temperatures. The second time, the ambient temperature was reduced, prompting just a 1 degree C increase in rectal temperatures. At rectal temperature +2.3, slow wave sleep (the deepest, most restorative portion of sleep) was increased. At rectal temperature +1, slow wave sleep was unaffected. This might sound like a big win for exercise-induced elevated body temperatures, but too much of a necessary thing isn’t always desirable. You want to maintain proper ratios between the various sleep cycles, and, as Dr. Emily Deans writes, spending too much time in slow wave sleep is typical of people with bipolar disorder and seasonal affective disorder, who often complain of lethargy, hunger, and weight gain. If you’re going to work out right before bed, give yourself time to cool off, perhaps with a cool shower, or move your workout to an earlier time.