Wrapping up warm for bed in winter could actually be harming your chances of getting a good night's sleep. Photo / 123RF
Wrapping up warm for bed in winter could actually be harming your chances of getting a good night's sleep. Photo / 123RF
As the winter chill sets in, it’s tempting to wrap up warm at bedtime in our comfiest pyjamas with the electric blanket switched on and the heating cranked up.
But chances are you could be getting a bit too warm and cosy before drifting off, and it’s not just bad news for your power bill - it could be keeping you from getting a good night’s sleep.
According to Professor Matthew Walker, a neuroscientist and psychologist at the University of California, Berkeley, many of us are trying to get to sleep in rooms where the ambient temperature - and thus our body temperature - is too high.
He says the ideal room temperature to help the average adult fall into a good-quality sleep is 16-18C.
“We need to drop our core body and brain temperature by one degree Celsius to fall asleep and stay asleep,” he shares with the Herald.
“It’s the reason that you will always find it easier to fall asleep in a room that’s too cold than too hot, so make your bedroom cold and make it dark like a cave.”
Kiwi sleep coach Gareth O’Donnell, the sleep ambassador for online bed retailer Comfi, founded by Susie Harris and Vicki Eriksen, agrees.
The ideal room temperature to help the average adult fall into a good-quality sleep is 16-18C.
Eriksen notes the wealth of sleep advice online can be “conflicting, often expensive and overwhelming”, whether it’s blue-light blocking devices, sleep supplements or expensive sprays and mists.
But O’Donnell reveals the trick to getting some quality shut-eye might just be cooling down.
We know how the body’s circadian rhythms and light and dark can affect how quickly we get to sleep, but research shows temperature is also a factor. We don’t necessarily fall asleep when it gets dark, but when our environment cools down, he reveals.
“To transition into deep sleep, we need to be able to cool our body,” O’Donnell points out.
“When your body cools, that’s when you start to detoxify the brain.”
When it comes to sleep, we’re all “unique and different”, he says - some of us run hot and some of us run cold. And while the temperature of your home in winter can affect your sleep “if you’re making it too cushy”, he adds that it’s “less about room temperature, it’s actually more about your regulation of your own body”.
Exercising and getting your heart rate up in the morning can help you sleep better at night. Photo / 123RF
“You get cooler and cooler as the night goes on, but the transition of light sleep to deep sleep happens when you cool. When you overheat, you automatically get pulled out of sleep, because heat’s a stimulus and produces cortisol. Cortisol and melatonin have an inverse relationship, they’re synergistic - one goes up, one goes down.
“The problem is, cortisol is a spiking or pulsing hormone, and melatonin is a saturation hormone. So for melatonin to be effective, it has to build and build and build across the night. But whenever it wants to, cortisol can pulse.
“It’s kind of like your body’s on ‘ready’ - it goes back to predation days when the fight or flight and threat response was real, when there was a tiger hiding behind a tree ready to kill us.”
It’s that spike of cortisol that can cause an adrenaline rush, waking us up suddenly - and can lead to insomnia.
O’Donnell recommends taking a hot shower before bed and using a hot water bottle at your feet to draw heat away from your core. When you heat your body, you force it to then cool down, which can help initiate sleep. If your body doesn’t cool down, you can end up tossing and turning and having vivid dreams.
And he reveals getting some exercise early in the day can help set you up for a better night’s sleep.
“Morning exercise, regardless of genetic profile - because some people are night owls and some people are morning birds - any form of exercise is beneficial, but it turns out that aerobic exercise is one of those things that just really affects all of us really, really well,” he says.
“Whether it’s intense or light, it doesn’t matter. Exercise in the morning will help you with regulation of temperature.”
Long-term, a lack of sleep can impair the mitochondria, which are responsible for generating energy in our cells - but getting your heart rate up regularly can help reverse that damage.
“We’ve seen this a lot with long-form Covid, [which] impairs mitochondria production, energy production. When energy production is compromised, human bodies function poorly,” O’Donnell notes.
“It doesn’t matter what type of person you are, exercise in the morning is beneficial for everyone, and will support better quality sleep and transitioning into sleep.”
With Comfi, O’Donnell shares a few more tips for getting a good night’s sleep.
Seven tips for deep, quality sleep
Keep your bedroom cold and your feet warm - a hot water bottle on your feet will help draw heat away from your core and bring about deep sleep more quickly.
Keep some plants in your bedroom to increase oxygen and decrease the room’s ambient temperature.
Get a serotonin boost in the morning - 30 minutes of sunlight increases serotonin and leads to the production of melatonin, which will help you sleep.
Stick to a regular sleep routine - try to go to bed and wake up at the same time each day.
Try gargling for three minutes before bed if you struggle with snoring or sleep apnoea to improve uvula tone.
Try some yin yoga stretches to help your body’s tissues release stress and engage the parasympathetic nervous system.
Learn something new - trying a new walking route or a new sport or hobby stimulates the part of your brain that controls REM (rapid eye movement) sleep.
Bethany Reitsma is an Auckland-based journalist covering lifestyle and entertainment stories who joined the Herald in 2019. She specialises in lifestyle human interest stories, foodie hacks (what can’t you air fry?!) and anything even remotely related to coffee.
