Now that Spring has sprung, and the hotter weather is on the way you might be finding it harder to get a good night's sleep! The Australian summer can affect your sleep quality, which may have the knock-on negative effect of health problems that sleep loss creates. 

Sit tight - as we will discuss some pro tips on how to cool down and sleep better.

How is sleep affected by heat?

Before we get into the ways to improve sleep, it's good to know what your body needs to fall restfully to sleep.

Your body's core temperature has to drop. And Once it has dropped, only slightly, your body releases melatonin. Melatonin is a hormone that helps regulate sleeping patterns for you. Pretty soon after your body has been releasing melatonin, you will drift off to sleep.

However, this means that anything that gets in the way of your body naturally releasing melatonin, such as heat (as well as many others we will discuss), you will struggle to fall to sleep. ^[1]

No doubt from many summers before, you have noticed that when you wake up after a stinking hot night, you feel groggy, and that's because your body did not sleep as well as it could have. Research has shown that as your body heats up at night, your body becomes stressed and releases cortisol (the stress hormone). A recent study has shown that people who sleep in a hot environment wake up with higher stress levels than normal due to elevated cortisol. ^[2]

When you don't sleep enough, you are right in thinking you have less self control for snacking and also being grumpy. The reason is that your body produces less leptin (the hormone that makes you feel full), and more ghrelin (the hormone that makes you feel hungry). Studies have shown that people with a lack of sleep will have higher levels of stress, and will feel hungrier, and also slightly insatiable as there's less hormone to make us feel full. ^[3]

This also confirms another study that links people with low levels of sleep (less than 6 hours per night) with higher chance of weight gain and obesity. ^[4][5]

There are many other health issues that stem from a lack of sleep, starting from issues such as mental health, sexual health, immunity and more. This info graphic covers most of the issues quite well:  

 ^{Image courtesy of Healthline.}

Getting a good night's sleep when it is bloody hot

When I think of hot summer nights and poor sleep, I am taken back to days in in January where it was so hot, I felt I was spending the entire night tossing and turning, with the fan simply blowing hot air at me. However, there are a few things you can do! 

Remember, the key is to lower your body temperature to feel slightly more sleepy, and then keeping it low so you can sleep peacefully all night long. 

Tips to lowering your body temperature

1. Get naked: While this can cause some issues depending on your sleeping arrangements, so if you must wear something, it is best to wear lightweight, loose-fitting pajamas made of linen or cotton that allow the skin to breathe. Try to avoid synthetic fabrics that insulate you and make you hotter. 
   
   
2. Take a cold shower: I know this isn't for everyone. And perhaps a luke-warm shower is the best you can do. However, if you can finish it off by gritting your teeth and a couple seconds of freezing cold, it will really help you to get to sleep after. 
   
   
3. Cool your extremities: If you aren't a fan of having a cold shower, then you could simply set your extremities in cold water, like your hands, head and feet. An amazing tip here is to run a cold bath, put in some ice, and then just put your feet in it for 5-10 minutes while doing some slow breathing. ^[6]
   
   
4. Wet cloths or ice packs on pressure points:  Wet face towels, ice packs and frozen peas on your wrists, neck and even armpits for short periods are amazing. These are places where the blood flows closest to the surface of your skin, and so the ice will help to cool you faster on these areas. 
   
   
5. Cold water mist: If you have a spray bottle, put cold water, and some ice cubes in it, and even a drop of lavender if you have it, and place it beside your bed. And spray yourself before bed. As the water evaporates, it will help to cool your skin and body down. 

 Keep your bedroom cooler

1. Try and prevent your room from heating up: Keep the cool air circulating, cover your windows earlier in the day to keep the room from heating up. 
   
   
2. Colder air can be your friend: If you have air conditioning, this is a no brainer. But if you don't a fan will do, and air-flow will definitely help, with an open window or door. Leaving an ice pack, bowl of ice cubes or frozen peas in front of the fan will cool the air and add some humidity. Studies have shown that fans are particularly effective when there is some humidity and much less so when it is hot and dry. ^[7]

     

 Other tips and tricks:

1. There are supplements you can try out as well which help with sleep, or making you feel sleepy. This can help a lot when it's really hot so you spend less time tossing and turning, and more time sleeping. One brand we love that has 11 scientifically validated ingredients to help with sleep it called Calm. . 
2. Meditation and breathing exercises to relax. 

Things to avoid in the evening:

1. Vitamin D: If you are going to supplement with this vitamin, please be aware that it suppresses the release of melatonin which you are trying to increase. 
   
   
2. Caffeine:  Caffeine in the afternoon and evening can disrupt your ability to unwind and create melatonin and adenosine (which make you sleepy). This unfortunately rules out chocolate in the evenings. 
   
   
3. Exercise:  Exercising increased your body temperature and may disrupt your ability to relax and prepare for sleep in the evening
   
   
4. Blue light: Try and put down your phone, tablet, laptop and even turn off your TV before bed. Once the sun is down, try to use bluelight blocking glasses and use "nightmode" on your phone. 
   
   
5. Foods that increase body temperature when digested: We are talking hot, heavy and spicy dinners here. 
   
   
6. Alcohol: We left this one until last as it's an unfortunate one. But alcohol can actually increase body temperature, and increase heart rate, which are two things you don't want when preparing for sleep on hot nights (or any night). ^[8]

In the heat of spring and summer, make sure you protect yourself from any health issues stemming from lack of sleep with some of our tips. Try the above out, and no matter how hot it is, you'll be sleeping like a baby. 

References

^[1] The Temperature Dependence of Sleep

^[2] Elevated airflow can maintain sleep quality

^[3] Sleep and obesity

^[4] Short sleep duration and obesity

^[5] Sleep disorders and the development of insulin resistance and obesity

^[6] Local body cooling to improve sleep quality

^[7] The Effects of Electric Fan Use Under Differing Resting Heat Index Conditions

^[8] Effects of alcohol on thermoregulation during mild heat exposure in humans