There’s a reason “chill out” is slang for rest. Humans generally fall asleep better in cooler environments. As the thermometer rises, so does our bedtime discomfort.
Our body temperature operates on a heat clock. It drops before sleep and further falls to one or two degrees below our waking temperature while we rest before plummeting again during REM sleep. The body’s nightly heat drops trigger our pineal gland’s production of the sleep regulating hormone melatonin. When it’s too hot, your body won’t cool down enough to produce melatonin. So you lie awake and sweat.
The obvious answer is to pump up the air conditioning. But AC isn’t always available. And considering its noise, expense and environmental impact, even when it is, you should probably try to limit its use as much as possible.
1. Keep a Cool Head
To sleep in summer, you have to keep a cool head, literally. A 2011 University of Pittsburgh School of Medicine small study indicated that cooling the brain helped insomniacs fall asleep by slowing activity in the frontal cortex. Twelve insomniacs and 12 healthy sleepers were provided with a cooling cap made of soft plastic and circulated water fell asleep with an average time of 13 minutes stayed asleep for 89 percent of the time they were in bed.
But don’t rush out looking for a cooling cap. The results for chronic insomniacs may not apply to the average sleeper. And, anyway, stores don’t carry the specialized medical caps used in the study. However, several cooling pillows and pillow mats, such as the cool water-retaining Chillow, are available.
2. Make Your House Work For Your
If you’re a homeowner, consider harnessing the cooling power of nature. A strategically positioned tree offers low cost, long-term climate control by absorbing 90 percent of the sun’s radiation while simultaneously cooling the ground below. A 2009 federal government study found that trees shading the west and south sides of 460 California freestanding houses reduced electricity bills by up to five percent and reduced emissions by 31 percent over a 100-year time span.
Trees don’t grow overnight, though. However, vines like ivy and Virginia creeper can quickly cover a structure and bring down temperatures. For the vine-averse, the U.S. Department of Energy recommends a number of energy efficient window treatments. The DOE endorses window awnings with particular enthusiasm, saying they can reduce solar heat gain in the summer by up to 65 percent on south-facing windows and 77 percent on west-facing windows.
3. Get Low
If you have access to an underground space, consider setting up a cot. Your basement or cellar will be the coolest place in the house. It’s also apt to be the dirtiest and creepiest, unfortunately, so you’ve got to do the math to decide if it’s a viable option.
4. Hydrate Wisely
You need to stay hydrated over those long summer nights. Drink more water than usual and limit diuretics beverages like caffeine and alcohol to avoid waking up from thirst or the need to pee.
5. Freeze Your Sheets
While you’re pulling out ice from the freezer, some sleep experts say you should consider stuffing bedding in the same space. To hold a chill, the sheets need to be slightly wet—not sopping, but damp. Leave them in the icebox for three to four hours. When the sheet’s not enough, try the “Egyptian method” of lying under a moist towel.
6. Strip Down
If sleeping under a wet cloth doesn’t appeal to you, maybe sleeping under nothing would. Opinions vary on the value of sleeping in the buff. Certainly, there’s less material to trap body heat. Unfortunately, the lack of clothes also means nothing absorbs or wicks away sweat, creating more discomfort.
7. Tire Yourself Out
While changing up your pillow might help, in my experience of battling heat-induced wakefulness, your greatest weapons are exhaustion and adaptation. I once lived in the middle room of a railroad apartment on the second floor of a brick oven-like building during a hot Brooklyn summer. We didn’t have central air and I didn’t have a window, so air conditioning was impossible.
If your overheated sleep experience is like mine, you’ll spend your first hot night rearranging your sheets, rolling and sweating while you cursing the summer. The next day will be an "Apocalypse Now"-esque haze of humid exhaustion. On the second night, you’ll have the same awful conditions, but so much fatigue you sleep through them.
It’s not pleasant, but it works.