Sleep hygiene doesn’t mean how clean your bed is. It’s about how well you set up your sleeping environment to really get the benefits of your sleep time. The people who typically get advice about sleep hygiene are people with insomnia or other sleep disorders – and there’s evidence that it is helpful for that. But even people who “sleep fine” might see major benefits from better sleep hygiene.
Those benefits don’t just cover things like feeling more awake and having more energy, although those are pretty great. Sleep is arguably as important as diet for weight loss (and it’s demonstrably better than “superfoods”) and arguably more important for overall good health. If you want to heal any kind of gut problem, recover from an autoimmune disease, or get your body back to a healthy state after years of restrictive dieting, sleep is your very best friend.
But really healing, restful, high-quality sleep doesn’t just mean conking out for 8 hours. Just because you’re unconscious for the “correct” amount of time doesn’t mean you actually get the benefits of a complete night of deep, restful sleep. It’s easy to get poor-quality sleep and be completely unaware of it, because…well, you’re asleep the whole time. But it’s a serious problem: poor-quality sleep has the same metabolic effects as sleep deprivation, including easier weight gain, reduced insulin sensitivity, and more cravings for junk food.
Here’s a look at how to get the high-quality sleep your body actually needs, with better sleep hygiene.
Light exposure is one important part of good sleep hygiene, because the right kind of light exposure can really help you get the most from your sleep. Exposure to different kinds of light tells your body about when to be awake and when to be asleep, so you don’t want to send mixed messages.
One big problem here is blue light. If you’ve ever looked at a TV or computer screen in a dark room, you’ve probably noticed how the light is kind of blueish. That’s called blue light, and it looks like early-morning light to your body. As far as your body is concerned, that blue light is an all-caps signal to BE AWAKE NOW. If you’re looking at that BE AWAKE NOW signal right up until you crawl into bed, it’s not exactly surprising that your body isn’t set up for a great night of sleep.
Back in the caveman days, we didn’t have an issue with blue light. We got blue light in the morning because that’s when it naturally occurs. In the evening, we got reddish light (from evening sunlight, fires, etc.) if we got any light at all. But today we have all kinds of technological options for getting bright blue light right up until bedtime, or even in the room while we’re sleeping. Getting blue light before bed reduces sleep quality no matter how many hours you spend asleep.
It's not just blue light either. Any bright light at night can deprive you of the benefits of sleeping, even if you technically sleep “enough.”
This study looked at over 100,000 women across the UK. The researchers found that light exposure at night was associated with a higher risk of obesity regardless of how long the women slept. The results confirm the results of a smaller previous study, where light at night was associated with obesity, blood lipid problems, and high cholesterol in elderly Japanese people. Again, these associations were after controlling for how long the people slept. Even if they slept for the same amount of time, people whose bedrooms were light had worse quality sleep, and a higher risk of chronic disease.
What you can Do:
- Avoid blue light (sun-spectrum lamps, TV screens, computer screens, smartphones) at night. If you can’t avoid it, wear orange glasses (you can buy these on Amazon for less than $20/pair; they look kind of dorky but it’s not like you’re going out to meet the Queen in them)
- Make your sleeping area totally dark. Get thick curtains or wear a sleep mask.
Another hidden sleep problem is noise. How many of us live in cities where every night is a constant stream of police sirens, honking vehicles, rumbling trucks, people out to party, train whistles, car alarms…Just like light, noise can reduce sleep quality without being so disruptive that it actually wakes you up.
This review goes over the way your body responds to noise while you’re asleep. Even if you don’t wake up, levels of stress hormones in your body increase, heart rate rises, and the normal phases of sleep get thrown out of wack. Typically, nighttime noise reduces the amount of time you spend in slow wave and REM sleep – that’s the “deep sleep” where all the really good repair and healing happens. You might be unconscious for the same amount of time, but more of it is “shallow sleep,” which isn’t nearly as beneficial.
Various studies have shown this effect from traffic noise, airport-related noise, and general “community noise.” Wind turbines may also be a problem if you live near them.
What you can do:
- Don’t leave the radio, TV, or music on while you sleep.
- Wear earplugs if you can’t escape the noise. Studies in hospitals have shown that wearing earplugs helps patients get to sleep even in a noisy intensive care unit.
- Consider melatonin. The same study above found that melatonin also helped – it basically helps blunt the stress/hormonal response caused by the noise.
Other Aspects of Sleep Hygiene – Effects May Vary
Light and noise don’t even begin to cover the typical range of sleep hygiene recommendations. This review goes over the actual evidence for a lot of those.
- Caffeine reduction depends so much on individual tolerance and personal reactions that it’s almost impossible to give one standard recommendation. The most the study could say was that it’s very clear that large doses (5-6 cups of coffee) right before bed disrupt sleep. No kidding, but other than that, it depends mostly on individual tolerance, age, sex, stage in menstrual cycle (for women), and other individual factors.
- Exercise probably does help, if you do it regularly, but it’s very hard to say what type or amount is best.
- Regular sleep/wake times: probably help, but most of the evidence is from people with no sleep problems, and may or may not be applicable to people with sleep problems.
Another common piece of sleep hygiene advice is to lower the temperature in your bedroom. But there’s not as much evidence supporting this as you might think. Of the few studies that exist, a lot of them are relatively extreme differences (i.e. “hot enough to be actively uncomfortable” vs. “comfortable temperature”). Sure, it’s probably disruptive to good sleep if you’re hot enough to be uncomfortable, but that doesn’t mean that cooling the room even more will help if you’re already feeling fine. This study actually found that during colder ambient temperatures, levels of stress hormones during sleep were higher, suggesting that you might get a better sleep in a slightly warmer room.
There’s certainly nothing wrong with trying any of these recommendations. Who knows: you could see a huge benefit! But if you want to do something with the strongest evidence for reliably helping most people, reducing light and noise would be the place to start.
Now Go to Bed!
Just to recap: sleep hygiene is important even for people who reliably sleep through the night. Just because you’re unconscious for 8 hours doesn’t mean you’re actually getting a quality night of sleep, and that could be just as dangerous to your weight and metabolic health as sleep deprivation.
Give your sleep quality a boost by reducing light and noise in your bedroom, and avoiding blue light before bed. It may also help to get regular exercise. Other interventions, like waking up at the same time every day, limiting caffeine, or sleeping in a cool room, could be helpful for some people, but there’s just not as much evidence to support them.
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