Why Does Fresh Air Make You Tired?

7 Min Read | By Lottie Salako

Last Modified 3 November 2023   First Added 27 October 2023

This article was written and reviewed in line with our editorial policy.

Getting outside is an essential part of a healthy lifestyle, but do you find yourself feeling sleepy after spending time in fresh air? Well, it’s not just you. Many people find an open window or a day of outdoor fun makes them more relaxed and sleepy. And while some of the reasons are obvious, there’s also some pretty interesting science behind how fresh air affects sleep. Let’s explore…

Why fresh air makes you sleepy

1. Increased oxygenation

Fresh air typically has more oxygen than air which has collected indoors. With these greater levels, you get better circulation and a healthier brain function, helping you feel calmer and clearer of mind, and, therefore, more likely to sleep.

2. Cooling effect

Your temperature naturally drops when you start to fall asleep, so a nice, cool breeze may help you feel sleepy. It’s all to do with our circadian rhythm – the biological clock which helps us wake and sleep.

Quite simply, this internal clock requires signals to keep it in tune. One of those signals is a slight drop in temperature. Now, whether our bodies cool down because they know we are about to sleep, or whether it’s a pre-requisite is by-the-by. Science has shown we need to cool down to allow us to drift off. And clearly, allowing fresh air into a hot or humid bedroom can help.

3. Being outdoors often equals exercise

Getting at least 30 minutes of exercise during the day has loads of benefits for your health, including helping you sleep. Even just going for a walk can improve your mood and cardiovascular health while burning off energy.

And similar to body temperature, exercise also regulates our circadian rhythm, improving our ability to fall asleep. Learn more about this in our article on how sleep and exercise are linked.

4. Nature can have an impact on sleep

You’ve probably heard that reconnecting with nature is good for you, but it really is true. Studies have found that people who spend more time in nature are happier, more relaxed, and more emotionally resilient. Given anxiety can impact our ability to snooze, the calming benefits of nature and fresh air are great for enhancing our relationship with sleep.

5. Reduced allergy symptoms

Good airflow helps limit the amount of allergens in the air. As allergies can result in symptoms like difficulty breathing and general discomfort, reducing their presence in our bedrooms is key to a good night’s rest.

One of the most common allergies is dust mites, which feed on – you guessed it – dust! Household dust is actually made up of a (pretty gross) combination of fine dirt, skin, clothes fibres, and hair. Regular cleaning and good ventilation will help reduce the dust in your home and how much it irritates you, especially while you sleep. Of course, hay fever is prominent too and you’ll actually want to limit open windows in this case. Check out our article for more on how to sleep with hay fever.

6. Increases in serotonin

There is some research showing how higher levels of oxygen cause an uptake in serotonin synthesis in the brain. This means that when you’re out in the fresh air, especially far away from urban pollution, you may get an emotional pick me up. Serotonin is also part of the sleep process as it creates melatonin, the sleep hormone.

birds eye view of a stormy, lively ocean.

Is ocean air better for you?

Being prescribed a trip to the seaside was very common in days gone by, but is there any truth in this old-fashioned treatment? There doesn’t seem to be any scientific evidence that sea air is better for you than inland, but living by the sea can impact your quality of life.

Speaking to Blue Health, Dr Lewis Elliot explains why those near the coast typically live longer and are happier.

My interpretation is that there are more opportunities for  physical activity and stress reduction by the coast that don’t exist inland.

People who live by the coast have a higher likelihood of taking up activities like swimming, surfing, and sailing. Other factors include proximity to nature, separation from urban stress, and eating fresh, local produce.

When it comes to sleep, there is a strong cultural association with the sound of waves and relaxation. Many of us find it easier to drift off when we can hear the sea. It goes beyond mere culture too. Ocean sounds, particularly waves lapping against the shore, are a type of pink noise, known for its calming and relaxing properties.

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Sleeping with the window open

Many have strong opinions on whether to sleep with the window open. For some people, it’s essential, and for others, it’s a deal breaker. But is there scientific backing either way?

Ultimately, the same benefits of fresh air exist for sleeping with the window open – it can help keep you cool, bring in more oxygenated air, and reduce potential irritants like dust. However, there can be some barriers to a good night’s sleep too, such as bad weather and noise! So, while fresh air can be good for you overnight, it doesn’t outweigh disturbances that keep you up.

Effects of poor ventilation

If your home lacks good airflow, it can be a bigger problem than you first imagined. Here are some of the most common issues to look out for:

  • Humidity: As warm-blooded creatures, we give off heat and moisture as we go about our daily lives. However, too much water in the air can make it harder to breathe and cause issues like sore throats.
  • Mould: Dampness can also cause mould to grow, which can cause skin irritation, respiratory issues, and general feelings of being unwell. The NHS have guidance on mould poisoning, causes, and how to spot it.
  • Carbon dioxide build-up: We inhale oxygen and exhale CO2, so it’s imperative that you have a good flow of fresh air to dispel the carbon dioxide and bring you more oxygen.
  • Odours: Bad smells happen, especially when we don’t have fresh air coming in. Over time, you might become unaware of odours in your home but it’s important to keep it clean and fresh for your mental and physical well-being.
We understand that some of the above may be out of your control. Some houses aren’t well insulated or have structural issues that cause damp and poor ventilation. If you’re in a rented property, Shelter has lots of advice on your rights regarding damp and mould in the home.

Other ways to freshen up the bedroom

Here are a few tips on how to give your bedroom a refresh with the window closed:

1. Dehumidifiers

Without fresh air coming in, you may want to find a way to reduce humidity indoors. This is especially important during winter when body heat, central heating, and the cold all battle it out and cause condensation. A dehumidifier will take water out of the air and make things more comfortable while also reducing the risk of mould.

2. Essential oils

If you want to freshen things up without leaving a window open, then essential oils can help. Scents like mint, lavender, and eucalyptus are all bright and invigorating. And you can always change just before bed to oils and scents which help you sleep!

3. House plants

Bringing nature indoors can be the answer if you don’t have access to a garden. Alongside the wider benefits of nature for sleep, some house plants like Aloe Vera and African Jasmine help reoxygenate the bedroom, so take a look at the best plants to help you sleep and revitalise your space.

All in all, if you’re struggling to sleep at night, it’s worth considering how much fresh air you allow into your room and how much time you spend outdoors during the day. In one way or another, the benefits are all linked to improving your quality of sleep.

And it’s not just fresh air which can help you sleep. Check out our post on the best bedroom colours for sleep or browse our Sleep Science Hub.

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