Ok, ok, not ALL the time, but the runner’s high is a real thing, and with over 858,000 people downloading the NHS couch to 5k app in lockdown 1, there must be something going for it! There are many elements that make running positive for your mental health, and it is increasingly being seen not only as great for the body, but for the mind too. So what is it about running that makes it so good for your brain and mood? Let’s look at the science.

1. A brain imaging study on endurance athletes and healthy controls at rest showed an increase in coordinated activity in some brain regions involved in executive functions (decision making) and working memory. They also found a reduction in ‘default mode’ activity – what our brain does when distracted, i.e. nothing very useful. This part of the brain is also linked to clinical depression, showing one pathway by which consistently running may reduce depressive tendencies and improve brain health. Interestingly, these are similar results to those seen in meditation – while running you’re turned into your surroundings, and what your muscles and breath are doing, not worrying about work, family or other stressors. So, running could be seen as a form of ‘active/moving meditation’.
2. Another study in mice showed that exercise breaks down a stress-inducing molecule Kyneurenine. The molecule itself builds up when you’re stressed, and can enter the brain, causing stress-induced depression and anxiety in some people. During exercise, there is a build up of an enzyme able to break down this molecule in the muscles, meaning it’s unable to enter the brain, protecting it against stress-induced depression. 
3. Beta-endorphins are released in running, improving mood post-run. The hormone is generally used by the body to reduce stress, and, as an endogenous opioid, is also linked to reducing pain. This happens not just over the course of one run, but also over the space of several months, meaning that the effects can last long after you’ve ended a run. This is potentially the source of the elusive ‘runner’s high’, which usually starts to kick in after 30 minutes of running. It’s also one of the reasons that runs can feel very hard at the beginning but get easier throughout – pain relief and a reduction in anxiety are both side-effects of our body’s reaction to exercise. 
4. While endorphins have long been credited for the runner’s high, it is likely that endocannabinoids play an even larger role. These are small enough to cross the blood-brain barrier (unlike endorphins), and act on the same receptors and systems that THC (the active ingredient of cannabis) does. This triggers feelings of euphoria, a sense of calm and reduced anxiety. There’s still a lot of research in this area and the mechanisms in humans still aren’t quite ironed out, but it looks promising!
5. Running (and exercise in general) also acts as a buffer to life’s stressors. In the same way that stressing out the body through exercise can lead to physical adaptations to cope, it can also lead to mental adaptations associated with resilience, which are then transferrable to other areas of life. Regular runners tend to be better able to cope with stress, thanks to the effects of
6. In rats, high intensity aerobic exercise such as running has been shown to literally create new brain cells. Up to a limit, running stimulates an increase in grey matter in the brain (beyond that limit, grey matter temporarily decreases, e.g. in extreme multi-stage endurance events – not surprising if you’re running 4,487km like those in the study!).
7. There are other endogenous benefits of running that may benefit the brain through indirect means, such as improved insulin response, improved immune function, improved circulation (including to the brain), increased energy levels, better sleep and improved focus (including the ability to multitask better!). 
8. Tangential mental health benefits of running include having a feeling of community (the running community is like I’ve never experienced before), having quantifiable goals and the sense of accomplishment that comes with that, which is transferrable to other areas of your life. Running has been shown to improve your self-esteem – placing the focus on what your body can accomplish and how it feels rather than what it looks like is one of the best to move away from being sucked into diet culture and the constant drive to lose weight. 

Evolutionarily, this all makes sense. As hunter gatherers, we would have had to chase prey for any miles, and having adaptations to a) make that feel good and b) reduce pain on long runs would have meant we were able to run further. And enjoying the chase/run would have meant more food for everyone, so better survival.

It’s important to note that many of these studied were either done on animals, or in small numbers of volunteers. However, anecdotally the benefits of running for the brain are multi-fold and substantial, and it’s great to see this backed by multiple studies. Hopefully we’ll start to see more of this in the coming years as the link between physical and mental health becomes increasingly clear. 

While these benefits mainly pertain to running, it’s also possible to get many of the same benefits through other forms of aerobic and anaerobic exercise. The benefits may be to differing degrees, but the important thing is that you find a form of movement that is enjoyable and sustainable for you – there’s no point in overdoing it on a sport that you hate. Moving your body in whatever way feels best is a good place to start! And if you’re just starting your running journey, keep it up! It is always hard at first (and at second, and at third), but the benefits are SO worth it. If you enjoy this topic, check out the book Endure by Alex Hutchinson. It’s fascinating and delves into the science further without being hard to read. 

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