Can't sleep in the heat? Scientists reveal simple sock hack that's guaranteed to help you doze off

Daily Mail​

21-06-2025

With the UK in the grips of 2025's first heatwave, many of us will be struggling to doze off amid the tropical heat.
If you can't sleep in the heat, scientists may have a counterintuitive solution.
Although it might seem bizarre, putting on a pair of socks before you head to bed could be the key to drifting off peacefully.
Studies have shown that this simple hack can help you fall asleep faster, stay asleep longer, and get a better night of rest.
Wearing socks has even been proven to be effective at bedroom temperatures up to 23°C - hotter than nighttime temperatures in many places across the country this weekend.
This strange trick works because our bodies' sleep and temperature regulation systems are deeply linked.
Professor Eus van Someren, head of the Department of Sleep and Cognition at the Netherlands Institute for Neuroscience, told MailOnline: 'The brain not only regulates body temperature, but also reads out skin temperature.
'It may interpret warm feet as the right moment to fall asleep.'
Why should you wear socks to bed?
Our core body temperature has a day-night rhythm, starting to drop in the evening to reach its lowest point around four in the morning.
That means the best time to sleep is when the core body temperature is on its way down.
Normally, your body would cool itself close to bedtime by sending blood to the skin in a process called distal vasodilation, which makes the skin hot.
Professor van Someren says this is like 'opening the radiator in the heating system in your home.'
When you put on socks, this increases the temperature of your skin and creates signals that your brain mistakes for the warming caused by vasodilation.
Your brain will then believe that it is time to fall asleep, and you will find it easier to drift off.
But wearing socks also helps you get to sleep in a more counterintuitive way.
When our skin becomes hot, the brain's temperature control system sends a signal to the body telling it to start venting heat by sending hot blood into veins near the surface.
This causes an increase in vasodilation, sending blood rushing to the skin and dropping the core body temperature down to safe levels.
Dr Michael Gradisar, head of sleep science and clinical psychologist and Sleep Cycle, says that wearing socks can trick the body into triggering vasodilation.
This, in turn, causes the core body temperature to drop and helps you drift off to sleep.
Dr Gradisar says: 'For people who need extra help warming their feet to assist their natural thermoregulation, socks can be helpful.'
That might be especially useful if you suffer from Raynaud's phenomenon, poor circulation, or other conditions that interfere with blood flow to the extremities.
A study published in 2018 by researchers from Seoul National University found that wearing bed socks significantly improved sleep even when the room was a toasty 23°C.
Those who wore socks to bed fell asleep 7.5 minutes faster on average and woke up more than seven times less frequently during the night.
How can you get the most out of this trick?
To make this trick work for you, it's important that you maximise the amount your core body temperature falls before bed.
Studies of skin heating techniques show that the best results were achieved when the feet were warmed about one hour before bedtime.
That means you should put on socks before you get into bed to trigger the core cooling process early.
Wearing the right material can also make a big difference, as you don't want anything that will trap too much heat or moisture.
Dr Gradisar says that 'natural fibres like wool help' since these offer the best balance of breathability and warmth.
Likewise, a study of sleepers conducted at 30°C and relative humidity of 50 per cent found that those wearing Merino wool sleepwear got a better night's rest than those wearing cotton.
Additionally, if you can find a way of cooling down your body while your feet stay hot, that will ensure the best temperature gradient for sleep.
Dr Gradisar recommends using a fan or other means to try and keep the bedroom as cool as possible.
However, with temperatures over 30°C forecast this weekend, it is also important to avoid making your feet too hot during the night.
Professor Bill Wisden, an expert on the neuroscience of sleep from Imperial College London, told MailOnline: 'Heat is like any intrusive stimulus such as pain, or noise or vibration. It wakes you up.
'Even if the socks help you go to sleep, having hot feet in summer will wake you up!'
So, if you do find yourself getting too hot as you doze, simply kick the socks off before falling asleep.
The increased vasodilation will linger for a while afterwards, and exposing your feet to the air could produce an even greater drop in core temperature, helping you fall asleep faster and stay asleep all night.
What if you find socks uncomfortable?
Many people may find the idea of wearing socks to bed an extremely unpleasant thought.
Luckily, if you are one of those people who like to let their feet breathe, there is another way to get the same effects.
Anything you can do to raise the temperature of your skin before getting ready for bed will trigger the same vasodilation effects as putting on a pair of socks.
Professor Wisden says: 'I recommend just before bedtime, take a hot shower or warm bath, even on a warm evening.
'At the end of the day, this raises the probability that you will drift off to sleep.'
You don't even need to have a full bath or shower if that seems like too much effort.
Studies have shown that simply bathing the feet up to the ankle in 40°C water for about 20 minutes, one to two hours before bed, helps people fall asleep about 10 minutes faster on average.
So, although it might sound odd, if you want to beat the heat this weekend, the best thing to do is to get as hot as possible before bed.