Too hot to sleep? Scientists have found a solution…
The mother of all heatwaves is upon us, as forecasters have said that there is a “40% chance” that the UK will reach its hottest ever temperatures this week. The Met Office has issued an amber-level warning over the temperature spike, and the TUC has urged employers to help workers cope with the extreme conditions by allowing flexible working to avoid the rush hour, home-working, keeping buildings cool and relaxing dress-codes.
But, while there are ways to try and stay cool in the day (drink plenty of water, wear loose linens, avoid travelling at peak times), hot weather can prove even more of a hindrance when it comes to bedtime. Those sweltering climes can leave us feeling uncomfortable and sweaty – and, as we lie listlessly in bed with fans whirring ineffectively nearby, we find ourselves becoming increasingly frustrated.
Opening the windows leaks disruptive street noise into our room, dampening the sheets is just plain uncomfortable and shedding our pyjamas can make things even worse. So what’s the solution to getting a good night’s sleep in the heat?
Well, somewhat surprisingly, it could be drinking a warm bevvy before bed.
Ollie Jay, a researcher at University of Ottawa’s School of Human Kinetics, has conducted a series of experiments into the effect a hot drink can have on your overall body temperature.
Vindicating grans everywhere, he and his researchers discovered that drinking a hot bevvy can actually cool you down, because it results “in a lower amount of heat stored inside your body”.
Why? Well, it’s very simple: the moment the hot liquid makes contact with the body’s temperature receptors, the brain tells the body to produce more sweat.
This sweat then cools on the surface of the skin, reducing the sensation of being too warm and ultimately, making us feel cooler.
The results of the experiment have made it clear that a steaming cup of tea or coffee is definitely a better option to an iced drink on a sweltering hot day.
But, when it comes to bedtime, warm milk is the answer.
Not only will it help to cool you down, but this bedtime drink also contains tryptophan, an amino acid that helps you produce serotonin and melatonin, hormones that help you to sleep. And, for vegans, it’s worth noting that almond milk, similarly, is thought to have serious insomnia-busting properties: it’s rich in B vitamins, calcium, iron, zinc, potassium and magnesium, all of which help regulate brain activity, relax the muscles and increase the secretion of sleep-inducing compounds such as melatonin.
Better still, drinking warm milk is an ideal way to avoid going to bed on an empty stomach: hunger pangs have been shown to keep to brain mentally alert, so it can be far more difficult to get a full night’s sleep if hunger hits during the night.
But, of course, a hot drink before bed isn’t the only way to cool down during a heatwave…
How to sleep in a heatwave
Chief sleep officer at Sealy UK, Neil Robinson, has shared his top tips for getting a good night’s rest throughout the summer months.
If you’re single, research has shown that you’re likely to be happier than your coupled-up counterparts – and you’re far more likely to get a good night’s sleep during a heatwave, too. Not only are partners more likely to disturb us in the night, but the extra body heat can make it even harder to get to sleep in the summer months. Sleeping in separate beds also means that we’re able to stretch out, rather than curl up, which helps body heat to escape.
Avoid exercise in the evening
Exercising too close to bedtime can not only leave you with a sudden surge of energy, but also raises the body’s core temperature, both of which makes sleeping in hot weather even more difficult. Instead, opt for exercise first thing in the morning to kick start your metabolism throughout the day, and leave you feeling ready to rest in the evening.
Use cotton sheets
It’s common knowledge that cotton clothes help to keep you cool in the summer due to the material’s breathability, and the same can be said about cotton bed sheets. The natural fibres help allow air to move freely and circulate through the fabric, which helps to keep you cooler through the night. If your bedroom is especially hot, opt for a light cotton sheet rather than a duvet to allow even more circulation.
Leave your feet out
While it may leave you at the mercy of the monster under the bed, sleeping with your feet out of the duvet or bed sheet will help to keep you cool. While many believe that we lose most of our heat through our head, this is not the case. In fact, our hands and feet are key to keeping cool, so keeping them out of the bed sheets will help to ensure a cooler night’s rest.
Check the TOG rating
An adult can lose up to a litre of sweat in one night and the thicker winter duvets that you enjoy in the colder months provide a completely different experience to lighter summer duvets. Despite common belief, the Tog is a scale of warmth in a duvet - NOT its thickness, ranging from 1 Tog through to 15 Tog. A duvet that traps and provides heat in winter (13.5 Tog plus), is likely to make you overheat in summer, so it’s important to have different products so that you can adapt between the seasons.
Invest in a cooling mattress
Many may not think it, but the mattress you sleep on can affect your temperature throughout the night. Investing in a high-quality mattress that features Smart Fibres, and more specifically Purotex and Tencel fibres, can help to keep you cool at night, as these have excellent cooling properties and prevent your body overheating during your sleep.
This article, which was originally published on 20th June 2017, has been thoroughly updated throughout.