Exercise and sleep

Exercise can help you sleep better, and good sleep can help you exercise better. It's the great circle of life. Fitness app, niix.fit tells us how to get the most out of exercising, with a view to help you sleep better.

Niix Fit's Nicki Philips

Exercise and sleep

How does exercise improve sleep?

We’ve all heard that exercise helps you to sleep better, but have you ever wondered why? Here’s a quick (simplified!) look at the science behind it…

1. Exercise triggers an increase in body temperature

Every night, your body temperature naturally falls as you start to drop off. The drop in temperature after exercise mimics the natural temperature drop your body normally experiences, and so you’re able to encourage your body to fall asleep faster. This is why it’s important not to exercise too late (and why you should take a warm bath rather than a hot one if you want to sleep better). The drop in temperature is important, but your body needs time for this drop to occur.

2. Exercise helps ease anxiety

Exercise can decrease excitement, anxiety and depressive symptoms by regulating some of the hormones that trigger such emotions, all of which can keep us awake at night. Most people know that exercise can make your body release endorphins, which are ‘happy hormones’. In truth, these hormones act on your brain so that pain isn’t perceived to be as strong, and can trigger a positive feeling of contentment in the same way that morphine does.

3. Exercise improves circadian rhythms

Finally, exercise can improve our circadian rhythms (body clock). Our internal body clocks are governed by cascades of processes and hormone releases. Cortisol plays a large part in this, and is involved in waking us up in the morning, as well as a response to stress. Regular exercise can decrease the amount of cortisol released in response to stress, and lower cortisol levels mean you shouldn’t be kept awake at night...

Will exercising at night keep me awake?

As with coffee, some people can drink a mug before bed and not feel the effects at all, nodding off easily. However, as a rule of thumb, nighttime coffee overload or a high-intensity cardio or strength workout right before bed is not encouraged if you have experienced difficulty sleeping post-workout.

If this is you, you should at the very least, give your body one-hour post-exercise to wind down and refuel before sleeping. Exercise, after all, raises your body temperature, triggers cortisol production, increases your heart rate, which in turn releases endorphins and can often leave us feeling energised.

How many hours of sleep do you need to recover from a workout?

Sleeping allows our body to repair and restore our muscles, bones and tissue from the strain we put on them during the day


While high-intensity exercise and running are likely to increase your need to sleep over time, the exact amount is unclear and down to your own body and how quickly it recovers. You know your body best, if after a hard training day or days you tend to wake up feeling more groggy and more fatigued, with more aches and pains than normal, it is likely that you need more rest. Aiming for those seven to eight golden hours are advised as the minimum to allow your body to kick start the recovery process and be able to continuously train and perform throughout the week. 

Woman running at sunset
Woman waking up in a Soak&Sleep duvet

Should I stretch when I wake up?

Yes. After a good few hours of lying in the same position, it is important when you wake to give your body a good stretch. Stretching is your body's way of getting your circulation going and encouraging flexibility and mobility through your muscles, joints and to the brain.

Morning stretches can help counteract the negative postural positions we tend to develop during our day (slouching in front of our laptops which results in tight chest muscles, long spinal extensor muscles and shortened hamstrings and hip flexors). Following a short morning stretch ritual can leave you feeling more energised and mobile as you head into the rest of your day.

Does sleep affect your running?

Many studies have seen that runners have a higher perception of effort for a given level of exercise, thus sleep deprivation makes everything feel harder. Although some studies indicate that physiologically, a lack of sleep does not necessarily affect performance, the body does not like to be pushed when tired. Sleep deficiency tends to affect the brain and the nervous system more than the heart, lungs and legs which allows performance to be sustained during short periods of sleep. 


Lack of sleep over extended periods, however, can affect your immune system while causing substantial hormonal imbalances, causing fatigue. This can ultimately negatively affect your running performance. Lack of sleep can also affect a person's ability to regulate their body temperature while running. The body’s ability to produce sweat to cool us down while we exercise can be hindered if not functioning correctly, causing tiredness, dizziness and leaving you feeling very lethargic. Having a consistent sleep schedule (the same bedtime and wake up time) each day can positively affect your running performance providing you are getting enough sleep (as near to eight hours as possible). Having said that, a few days of broken sleep is unlikely to affect your overall performance.

How much sleep should a runner get?

The physical stress of running means you should seek more sleep than someone who does little physical activity. This is because your body needs to recover from the strenuous movements it has gone through - this process only kicks in when we sleep. These all important hours in bed can also be key to avoiding injuries…allowing tendons, muscles, bones and ligaments time to recover and avoid exercise stress- related injuries. On average, research suggests that adults should aim for seven to eight hours of sleep a night. Elite athletes are encouraged to sleep for eight to ten quality hours.

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What do you think? Does exercise help you achieve better, deeper sleep?