Posted by Dr Sophie Bostock - Sleep Expert on 20th Sep 2022
Sleep Better: The Magic of Exercise
Sleep and Exercise
If you could design the ideal sleep solution, what would it look like?
I’d suggest it would:
- improve your ability to fall asleep, stay asleep, and wake up well rested
- make you feel good
- make you healthier
- reduce stress
- be no or low cost!
There is something you can do which ticks all those boxes, and it’s as simple as getting the body moving, every day.
Exercise and sleep have a reciprocal effect - in other words, more of one, typically leads to more of the other. When we sleep well, we have more energy, more self-control, and a greater capacity for endurance exercise.
Being physically active helps to regulate all three of the main systems which influence your sleep.
1.Your circadian rhythms
Movement is one of the signals to our internal clocks that it’s daytime, and time to be alert. Being physically active in the early part of the day can help align our internal rhythms with the light-dark cycle of the sun, and help us to feel naturally sleepy at nightfall. Physical activity late at night however can delay the clock, so it’s recommended to stop intensive exercise at least an hour before bed.
2. Sleep Pressure
The short term effects of exercise include the release of adrenaline and endorphins which make us more alert - so it can be a great way to stay awake! However, when we expend energy, we also release adenosine, a signalling molecule which makes us drowsy. Once the activity comes to an end, the build up of adenosine will increase our pressure to sleep, and make it easier to fall asleep and stay asleep.
3. Stress System
While exercise itself behaves as a ‘stressor’ which activates the body, after exercise, our stress hormones, blood pressure and heart rate all decrease. Exercise seems to make us more adaptable at switching off the stress response, leading to lower levels of anxiety and physical tension. Exercise increases the amount of deep, slow wave sleep, which is very physically restorative.
Exercise also strengthens our immune system, helps regulate appetite and blood sugar and improves emotional resilience. This is in addition to making us stronger and fitter!
Regular physical activity can reduce the risk of type 2 diabetes by up to 40%, reduce the risk of depression by up to 30% and reduce the risk of colon and breast cancers by up to 20%.
It’s not clear from the research exactly how much exercise, or how long for, we need to do to sleep better. It is likely to partly depend on age, our baseline levels of fitness, and the type of exercise we most enjoy… If you find exercise painful, or unpleasant, you’re much less likely to repeat it and it will probably have the reverse effect on your stress levels.
Several studies suggest that cardiorespiratory fitness is correlated with better sleep, suggesting that regular moderate to vigorous exercise - which gets the heart rate going - is an important factor. Studies have found that this can be achieved in a variety of ways.
For example, the following ‘recipes’ all led to improved sleep in research studies:
-30 min moderate intensity cycling 3 times a week
-30 min walking, calisthenics or dancing daily
-60 min moderate-intensity running 3 days a week
A recent review of physical activity interventions in older adults found that the most reliable effects on sleep were for programmes which involved moderate intensity exercise (where you’re still able to talk) at least 3 times a week, for 3 to 6 months ( Vanderlinden 2020).
However, positively, one study in older women found that a single session of 54 minutes of moderate intensity activity (on a treadmill) improved sleep quality the same evening ( Wang 2014).
If for any reason you’re not able to engage in heart-pumping cardiovascular exercise, the good news is that there can also be benefits with lower intensity training - but it may take time. Some studies have found that ‘mind-body’ exercises such as yoga and Tai Chi can have positive effects on sleep when practiced regularly, several times a week.
A Brazilian study recruited adults aged 30 to 55 with chronic insomnia who didn’t exercise regularly. They completed a 4 month programme which involved either 60 minutes of stretching or 60 minutes of weight training, 3 times a week. At the end of the 4 month programme, both groups significantly improved their sleep quality compared with a control group that didn’t exercise ( D’Aurea 2019).
The UK physical activity guidelines recommend that adults engage in at least 150 minutes of moderate intensity exercise per week or at least 75 minutes of vigorous intensity exercise per week (breathing fast and difficulty talking), or a combination of both. To keep muscles, bones and joints strong, it is also recommended to build strength on at least 2 days a week by doing resistance training at the gym, or yoga.
These recommendations have been created to help support better mood and health, and are also likely to have beneficial effects on sleep. Even if you don’t have time to do 30 minutes or 60 minutes at a time, a short walk could still make a difference to your mood and stress levels on a day when you’re really busy. To supersize the beneficial effects of exercise on sleep, do it outside.. exposure to natural daylight will help to sync your body clocks with the light-dark cycle of the sun. The most important thing to remember with exercise is that every little helps.
