November 4, 2022

Eyelid Warming: A shortcut to better sleep?

Eyelid Warming: A shortcut to better sleep?
Brandon Hauer, PhD
Time Read
8
min

TL:DR: Gently warming your eyelids can boost your sleep in the same way that a warm bath before bed does.


More than ever, we’re constantly connected. We’re plugged in for emails, for messages, for late night sessions to catch up on work. And when we finally do “clock out”, we spend our time watching Netflix, or scrolling through our phones.

If you could use “just another half hour” in the day for all of this, it’s all-too-easy to take it from your sleep.

Or maybe you’re so wound up after another full day of screens and connections that it’s hard to fall asleep, so you put off doing it for as long as you can.

Let’s talk about what’s happening when your body is trying to get some shut eye.

 

Cooling Down As You Sleep

Every time you fall asleep, whether you’re aware of it or not, you cool down. Your core body temperature drops by a couple degrees as you start to doze off. In fact, the lowest your body temperature will get is about 2 hours before your natural waking time.

This process, known as thermoregulation, is a powerful mechanism which allows your body to automatically interact with the external world.

You could think of warmth as part of a “nesting” behavior – I’m safe and secure, and warm enough to fall asleep soundly for the full night.

You’ve probably experienced the inverse of this yourself: It’s mid-July, swelteringly hot outside (a rarity here in Edmonton, but hey, we have our moments), and the “trusty” old air conditioner is broken. Consequently your bedroom is too warm, and you toss and turn for what feels like an eternity.

Why?

Your body can’t cool down! You have no natural way to radiate away that heat, and your body stays stuck at the same temperature from the evening into the night.

This is why opening a window or cooling your bedroom down a few degrees before bed can be so beneficial for your sleep. It lets your body thermoregulate appropriately, so that you can cool down in the evening.


Warming up… to cool down?

But maybe you’ve also heard the old adage that “a warm bath before bed helps you fall asleep.” Must just be an old wives' tale, surely, especially now that you’re armed with this knowledge of how important cooling down is.

In fact, it couldn’t be more true!

You see, while a warm bath is relaxing – maybe you’ve got some candles, a good book, and you’re not stressed about checking emails on your phone – there’s more to it than that when it comes to falling asleep.

The warm bath, of course, heats you up. Your body’s response to this is to bring blood closer to the surface of your skin, in an attempt to regulate your temperature a bit more easily. Even after you get out of the bath, your body temperature can stay elevated for 2 hours (or perhaps the whole rest of the day).

What that means is your warmed up body, with blood near the surface of your skin, continues to be able to radiate that heat away much easier.

Technically, there are a few places on your body that are super thermoregulators: those places with so-called glabrous skin. Glabrous skin, fairly simply, is just skin that doesn’t have hair follicles. It is also very dense in capillaries, letting your body exchange heat through the surface of that skin much easier.

The most notable areas of glabrous skin – again, your super thermoregulators – are your palms, the soles of your feet, and your face (and especially your eyelids).

What this means is when you tuck into bed – even if it’s hours after your warm bath – your hands, feet, and face continue to very effectively exchange heat. This helps you cool down quicker, naturally signaling to your body that “Oh, it must be time for sleep now.”

Recently some very clever people started capitalizing on this phenomenon. “A warm bath sounds like entirely too much work,” they presumably said. “I don’t have that kind of time!” So what did they come up with instead?

 

Periocular Warming

Periocular warming is a fancy way of saying “gentle eyelid warming”.

When you warm the glabrous skin in your eyelids, your body associates this with whole body warming. It assumes that, because your periphery is warming up, you must have excess temperature to lose.

In effect, this tells your body that you must be warm enough, and can start cooling down to fall asleep.

We’ve seen both in sleep laboratories and at home that even a few minutes of periocular warming can reduce the time it takes you to fall asleep.

Moreover, it can actually improve the quality of your sleep.

For instance, one study sent participants home with eye warming devices. They instructed participants to wear their warming eye masks for 10 minutes before bed, for 5 days. Researchers recorded their brain activity with an at-home electroencephalography (EEG) device, and also had participants report on their sleep each day.

The results were fantastic: Periocular eyelid warming to 40°C before bed significantly improved:

  • Sleep quality
  • Time to fall asleep
  • Feeling refreshed in the morning
  • How much deep, restorative slow-wave sleep they got each night (increased delta frequency activity in the EEG recordings)

Effectively, the researchers gave participants the sleep-boosting benefits of a warm bath, but without having to leave their bed.

Findings like these helped inspire the technical features of REST. We encourage users to use a warming session ~40°C/ 104°F, for 9-12 minutes before bed. This is the default “Rest” setting that comes built-in with the device.

We’ve also combined this heating cycle with other features like breathing cues and meditative practices to form our patented Thermal Meditation™ experience. REST is designed to help you form a regular habit for optimizing your sleep and wellbeing.

So whether you’re trying to or not tonight, as you fall asleep, your body is going to cool down. Why not help it along and get a boost to your much-needed sleep with either a warm bath or shower, or a 10 minute eyelid warming session with REST?

Your body will notice the benefits even before you do.