Your Brain on Exercise

Exercise Improves Mental Health

It is likely common knowledge by now that physical exercise is good for overall health and emotional well-being, however I think it’s worth taking a slightly deeper dive into this subject, as I find that more in depth knowledge can help people to feel motivated to create new habits. Hundreds of research studies have demonstrated that the benefits of regular exercise go far beyond physical health.  Positive effects have been shown for anxiety, depression, bipolar disorder, ADHD, psychotic symptoms, suicidal ideation, insomnia, and cognitive aging. 

For example, individuals with major depressive disorder who exercise regularly may need about half the dose of antidepressants compared to those who do not exercise; for me, this evidence creates a powerful argument for psychiatrists to “prescribe” physical exercise to augment medications in patients with depression.   Physical exercise can also improve attention and executive functioning in children with ADHD, reduce anxiety in individuals with anxiety disorders, improve symptoms of psychosis in adults with psychotic disorders, and reduce the risk of developing suicidal ideation.

In non-clinical populations (individuals who do not have a mental health diagnosis), exercise can reduce symptoms of anxiety and depression as well.

How Does it Work?

We don’t know with 100% certainty exactly why exercise improves mental health, but we have a pretty good idea of at least a few likely mechanisms in the brain.  We know that when people exercise, it leads to an increase in molecules in the brain that reduce neuroinflammation, protect neurons from dying, and promote and stabilize new connections between neurons in areas of the brain that are important for regulating mood and learning.  These molecules include irisin (released by skeletal muscles during exercise), BDNF (brain derived neurotrophic factor), the same molecule that scientists believe is responsible for the effects of some antidepressants, and dopamine, a neurotransmitter responsible for motivation, learning and memory, regulating attention, and reinforcing pleasure-seeking behaviors.

I can think of very few down sides to exercise, other than mild and temporary muscle soreness, provided you are exercising in a responsible way, with guidance when needed.  The way I like to describe this to my patients who may not feel motivated to exercise, is that it is kind of like taking a medication, but without the side effects.  And yes, I do “prescribe” exercise to my patients!

How Much Exercise is Enough?

There are a range of ideas about this, and the answer really depends on the specific research study that is being quoted.  In general, following physical activity guidelines from the American Heart Association and U.S. Department of Health and Human Services is a good starting place: 150 minutes of moderate intensity aerobic exercise, or 75 minutes of vigorous aerobic activity per week for adults, and 60 minutes of moderate to vigorous physical activity per day for children and teens. 

How Will you Know if it is Working?

I would suggest identifying the specific changes you want to see in your mood and/or symptoms, and keeping track of these over time. Some people start to notice benefits within 3 weeks, and most notice improvements in their target symptoms within 12 weeks.

Your Brain on Nature

Exposure to Green Spaces Changes Your Brain!

You may have experienced the calming effects of spending time in nature, but are you aware that there is a neurobiological basis for this calming experience?  Scientists who study the structure and activity of the brain have known for some time now that spending time in nature can change the brain. 

Specifically, the part of the brain that is associated with fear, anxiety, and trauma-related disorders is less active after spending time in nature.  Moreover, the overall structural integrity of the brain is improved by living in proximity to a forested area, presumably due to spending time in that same forested area.

These findings suggest that you can reduce feelings of stress and anxiety by spending time in green spaces, whether that is a park, a forest, a botanical garden, or your backyard. 

How Does Nature Impact Mental Health?

What do we know about access to green spaces and mental health?  Recently, the entire world experienced a major stressor in the form of a global pandemic that changed the way we work, play and relate to each other.  During the pandemic, those who spent more time in nature were less likely to experience depression and anxiety, possibly due to reduced experiences of stress. 

We also know that time in nature can improve memory, attention and impulse control, both for typically developing individuals, and those with attention and impulse control challenges, such as individuals with ADHD.

The benefits of time in nature go beyond mental health as well, and include improved academic performance, improved cognition, and improved physical well-being.

How Much Nature is Enough?

Well, the more the better, however the few research studies that have tried to answer this question have shown that the most benefit from indoor green spaces is achieved when 10-25% of the space is filled with plants. 

The benefits of time in outdoor green or blue spaces can be seen after just 5 minutes, however the more time you spend in nature, and the more frequently natural spaces are visited, the more likely you are to benefit. 

I hope this knowledge motivates you to go outside, find a green (or blue) space, and enjoy the calm and clarity that comes from your time in nature.