Discussions of mental health are growing in popularity nowadays, especially since the Covid-19 Pandemic began. The repeated message has been that finding time to exercise, and in particular to get outside and exercise, can greatly benefit our mental health.

A recent study conducted by Chekroud et al. (2015), which involved over 1 million U.S. participants, showed that people who exercised more frequently experienced fewer days of poor mental health. The results also showed that about 45 minutes of exercise, three-five times a week, is optimal for seeing benefits to our mental health. You may have heard that the World Health Organization recommends that we get at least 150 minutes of exercise a week; these recommendations align.
So what is it about physical exercise that leads to better mental health? According to Mikkelsen et al. (2017), there are a variety of physiological changes that take place as a result of exercise, such as an increase in endorphin levels, neurotransmitter production, body temperature, and mitochondrial function. Endorphins are hormones which are often referred to as natural painkillers and therefore they are mood boosters. Mitochondria are organelles that help to change the energy we consume into energy that can be used by the body.
The above stated physiological changes then lead to psychological changes (leading to improved mood states). The psychological changes are distraction from unwanted feelings of anxiety and/or depression, positive feelings associated with mastery and self-efficacy, increased energy and better concentration, and a stronger immune system.
Once you get into a routine of exercising regularly, you will definitely notice the changes in your mood. On the mornings when I was at work and had skipped my morning walk, I felt less energized, more anxious and much crankier! Mikkelsen et al. (2017) explain that any type of exercise that you enjoy will benefit you mentally, whether it is walking, gardening, yoga, team sports, or running, etc.
Your Brain on Exercise -Check out this short video which explains what happens to your brain when you exercise. When you exercise, your brain interprets your increased heart rate and movements as stressors and in response it releases chemicals that protect you from stress: endorphins and something called BDNF.
The video explains that “BDNF repairs and protects your memory neurons and clears your mind so you can make good decisions”. In other words, the release of BDNF is part of the reason why exercise leads to better concentration, improved mood and increased energy. Endorphins are said to “reduce feelings of discomfort” and “cause pleasure” (as previously explained, they are known as mood boosters). Interesting stuff!
References
Elbe, A-M., Lyhne, S. N., Madsen, E. E., Krustrup, P. (2019). Is regular physical activity a key to mental health? Commentary on “Association between physical exercise and mental health in 1.2 million individuals in the USA between 2011 and 2015: A cross-sectional study”, by Chekroud et al., published in Lancet Psychiatry. Journal of Sport and Health Science, 8(1), 6-7.
Mikkelsen, K., Stojanovska, L., Polenakovic, M., Bosevski, M., Apostolopoulos, V. (2017). Exercise and mental health. Maturitas,106, 48-56.