Health

Fitness for mental fitness

Exercise can make you happy, smarter, more aroused and less likely to get depression. Nelson’s own Dr Marissa Kelaher explains how.

While we all hear about how good exercise is for mental well-being, what does the research actually show?

Scientific studies are often divided among population groups and look at patterns within large numbers of people, versus clinical trials where an intervention takes place, and the effect is measured.

In both areas there is amazing evidence which shows exercise is a powerful tool for use in preventing mental health issues from occurring, and in treating them. For example, large population studies from around the world consistently show that regular exercise (150 minutes per week) reduces the risk of depression by around 30 per cent. That is just as effective as many antidepressant medications. And if you’re pushed for time, even shorter, more intensive exercise has a similar effect. This might be running 10 minutes per day or doing 10 minutes of high intensity training (HIIT). Exercise is highly potent in guarding against mental health problems in young children and teenagers as well. Clinical trials have backed up these findings. One trial compared a group of people prescribed exercise against a group prescribed antidepressants, and one group given a placebo. A follow up four months later found that regular exercise was a remedy as effective as those who took antidepressants. Each group improved significantly over that which took the placebo, but even more impressively, the people who exercised remained well when followed up a year later. The conclusion was that it prevented a relapse into depression. Exercise is also proven to help with both anxiety and posttraumatic stress disorder (PTSD). It is known to help ease the frequency and levels of anxiety symptoms, and the severity of panic attacks. Exercise also appears to “rewire” the brain out of the cycle of thoughts that occur after trauma, therefore helping to ward off the onset of PTSD.

So how does it actually work?

Scientists have done some interesting research on this, using blood tests to measure levels of stress hormones as well as “happy hormones” before and after exercise. They also use functional magnetic resonance images (MRIs) to look at how the brain changes in response to exercise. These studies have found that exercise works by: • Reducing cortisol levels (stress hormone) • Increasing the size of your hippocampus (the part of the brain that stores memories and regulates emotional responses - this also makes you smarter and your brain age slower!) • Releasing hormones that make you feel good (endorphins) and those which make you happy (serotonin and dopamine). • Increasing blood flow to the brain and stimulating the release of BDNF (a hormone that causes brain growth and rewiring). • Reducing inflammation (strongly linked to depression). • Triggering vagus nerve activation (the “rest and relax” part of your nervous system). Exercise also improves sleep, concentration, libido, selfesteem, and energy levels - all of which are symptoms of depression or anxiety. If you exercise in nature, such as a hike in the mountains or a swim in the sea, the effects are even greater. Studies have shown this can reduce stress levels by up to 60 per cent. Motivation is often a barrier to exercise and if you’re feeling down, starting an exercise plan can feel overwhelming. The secret is to begin with small, achievable goals and slowly build up from there. Even a 10 minute walk each day can really help, but try making it a regular habit. The more you do it the easier it will get - new habits need about four weeks of consistency to become inbuilt. Find an activity you love doing and you’ll soon notice the difference.

Dr Marissa Kelaher is a Nelson based GP who runs lifestyle, nutritional medicine and plant-based health clinics. She is based at Nelson Family Medicine. Check out Marissa’s blogs and health and wellness tips at thesimplicitydoctor.com or on Facebook and Instagram @thesimplicitydoctor