There aren’t many locations blessed with great year-round weather. Most of us have to deal with seasonal changes, and in the era of climate change, everyone will face extremes of temperature and weather more frequently.
One of the more subtle effects of such fluctuations is on our sleep patterns. Temperature and humidity are among the most critical determinants of sleep.
Setting the thermostat and having the local air-conditioning company keep your system in good shape are the obvious first responses to this challenge.
But there are other ways you can leverage the influence of thermoregulation to get better sleep every night, and many of them don’t even cost energy.
How temperature affects sleep
As more of us experience difficulty getting the rest we need each night, we often turn to the internet for answers. Sometimes, these tips and ‘life hacks’ are effective, but your mileage will vary. Not every source is reliable, and some actions are situational.
A better approach would be turning to science to understand the underlying mechanism of how the thermal environment affects sleep.
Our bodies have internal circadian rhythms based on a 24-hour cycle. These rhythms make us feel alert and energized at certain times of the day and drowsy at others.
They also influence other things, such as eating habits and hormone release, but are best-known for their association with sleep. This is the basis of the popular concept of ‘morning larks’ versus ‘night owls.’
Our genes determine individual variations in circadian rhythms. But these internal biological clocks are also affected by the environment.
Our body temperature fluctuates in relation to sleep. When the peripheral skin temperature decreases, it induces the sleep response. In turn, sleeping causes our core temperature to drop. To prevent discomfort and maintain the sleeping state, the body increases circulation to create a warm microclimate through areas of skin contact.
The overall mechanism seems designed to conserve energy. We expend energy to maintain a stable body temperature. Sleep is a chance to lower metabolic activity and recharge, and ideally, our sleep-wake cycles are in sync with these temperature fluctuations.
Quality of sleep matters
Another aspect of sleep that’s affected by this mechanism is its quality.
Sleep cycles through stages. The first stage of light sleep is a transition from wakefulness that only lasts 5-10 minutes. Stage 2 is when body temperature drops and breathing and heart rate stabilize. It lasts for about 20 minutes. From there, you move on to stage 3 or deep sleep.
The first three stages are collectively called non-rapid eye movement (NREM) sleep to differentiate them from the fourth stage of REM sleep. During this stage, brain activity increases and we experience dreaming.
The progression through these stages isn’t linear, as we need to go through the first three NREM stages, then back to stage 2 before going to stage 4.
And science tells us that the benefits of sleep vary according to the stage. NREM is more restful, especially in stage 3. On the other hand, REM sleep is when your brain consolidates memories and lessons, leading to improvements in performance.
Pushing the temperature buttons
The bottom line is, we need both NREM and REM sleep to gain those benefits. And we can ill-afford interruptions that reset the cycle, wake us up entirely, or prevent us from getting adequate rest.
You can tackle many other factors, such as putting away devices before bedtime or minimizing work-related stress. Compared to those, however, thermal regulation is the easiest lever to control, and it will influence your sleep throughout its duration.
Start with setting the thermostat to a comfortable temperature. Then pay close attention to your microclimate. Bed covers, pillows, blankets, clothing, and even the presence of another person when you sleep, all of these things can generate warmth.
On cool nights, these things mean you might need less heating. During warmer seasons, you can strip away a few layers.
You can also induce your body to sleep faster through the mechanism of peripheral heat loss. If you keep your hands and feet warm before going to bed, you make it easier to start dissipating that warmth once you’re ready to sleep.
A warm bath can work wonders in the same way. If you take a dip, not immediately before, but maybe an hour before hitting the sack, it can speed up the onset of sleep and favor deeper NREM stages.
Finally, consider abstaining from food 2-3 hours before bedtime. This has nothing to do with concerns about your weight. Regardless of what you eat, remember that consuming food stimulates our metabolism, messing with your circadian rhythm and ability to fall asleep.
Meta title: How to Use Temperature to Get Better Sleep
meta desc: Before you try difficult interventions or spurious sleep hacks, see if these science-based strategies will result in easy, effective improvements in your resting habits.