Exercise and mental health link proven by scientific models
A link between exercise and mental health is now accepted by people from all walks of life to be true.
Both avid gym junkies and the most conservative medical researchers will generally accept that exercise boosts mental health and performance the same as it does physical.
In many ways the link between exercise and mental health is growing in stature. Evidence-based scientific researchers are coming to accept that physical exercise affects the mental health of a vast majority of people.
Two major studies illustrate the growing interest in this link, following which there have been countless others:
Exercisers have a lower incidence of depression and anxiety disorders. (De Moor, Boomsma, Stubbe, Willemsen, & de Geus, 2008)
Exercisers show cognitive advantages, specifically in frontal executive functions. (Hillman, Erickson, & Kramer, 2008)
It can be a touchy subject however, and not just for scientific minds.
Whilst most exercisers prefer to talk about their 18-inch biceps or their new readings on the scale, there is no harm from equally talking about how exercise makes you feel.
So if we accept that there is some link between exercise and mental health, what are the actual mechanisms that generate this link?
Scientific links between exercise and mental health
As ever, when dealing with matters relating to mental health and the mind, it’s not straightforward. Physically we can see muscles grow or body-fat reduce, but mental and emotional changes can be less obvious.
In fact, there are many mechanisms by which exercise is thought to influence mental health. It is likely that most people benefit from some combination of different mechanisms, without a single one able to be identified as the exact cause.
Let’s have a look at the possible reasons for why exercise can boost mental health.
1. The everyday answer: more oxygen and bloodflow
Exercise improves blood circulation and supplies the brain with more oxygen. The increased oxygen and bloodflow clears the mind, making thinking clearer and life in general a little more tolerable. This is the most obvious link, and the one that most of us have heard before.
2. The Endorphin Hypothesis
The endorphin hypothesis proposes that wellbeing increases during exercise as a result of the release and subsequent binding of endogenous opiods - endorphins - to receptor sites in the brain. A study by Steinberg & Sykes in 1985 first proposed this mechanism.
The endorphin hypothesis originated from early research on rat brain tissue that revealed significant increases in opiate receptor occupancy after the rats had been forced to exercise (studies by Pert & Bowie, 1979; Wardlaw & Frantz, 1980). A 1982 study by Christie & Chesher also demonstrated that mice can become ‘swimming junkies' if they exercise regularly.
The endorphin hypothesis remains to this day one of the most popular explanations of the psychological benefits of exercise.
Exactly how or when this mechanism works remains a mystery. Dr. Jack Raglin of Indiana University, an authority on exercise and depression, suggests the that endorphin release is not always present: "We do know that the benefits or effects of exercise are not dependent upon endorphin release, because we find mood improvements and psychological benefits occurring in exercise doses that are too mild to result in much endorphin production.”
3. The Hyperthermic Model
This model suggests that the primary reason we get a wellbeing boost during exercise is due to the elevation in body temperature that occurs when we are in movement.
The basic belief that elevating body temperature can be therapeutic is not new, as use of saunas and steam rooms indicates.
A study from Horne and Staff in 1983 concluded that high intensity exercise and associated body heat promoted increases in slow wave sleep, which in turn is very relaxing physiologically.
Perhaps this is why we sleep better after exercise?
4. The Distraction Hypothesis
An interesting explanation for the positive relationship between exercise and mental health is the Distraction Hypothesis.
A 1978 study by Bahrke and Morgan compared the effects on anxiety of walking on a treadmill, meditating or resting in a comfortable chair. It was found that all three groups showed decreased levels of anxiety after treatment. It was concluded that exercise can serve as a useful distraction or ‘time-out’ from stressful stimuli and feelings.
Points of interest
The mechanisms described above – and the studies that led to them - propose scientific explanations for how exercise improves mental health.
It is interesting to note:
1. They are all fairly old studies – indicating that scientists and scholars have been thinking about this connection for a while.
2. All of the links are of a short-term nature – they are physical responses that directly come about as a result of exercise undertaken. You’ll get the benefits from them during exercise and no doubt for a period after.
3. These models seem fairly intuitive; we are familiar with the responses they describe, and have no doubt thought about them before ourselves. If we put those models into everyday language, we would say:
The endorphin hypothesis: “The ‘runners’ high”
The Hyperthermic model: “I am more restful and I sleep better if I have exercised”
The Distraction hypothesis: “I forget about my daily worries when I’m at the gym”
We know these responses, but it’s nice to know there are official terms for them, right? The links have been found through scientific tests – it’s not just you!
The 'runners high' is familiar to many runners, and serves as a major motivator
Longer term benefits
Exercise can benefit mental health in more holistic ways, beyond the instant feelings of wellbeing discussed above.
Indeed, current research is focusing on use of exercise to directly treat many long-term mental and emotional illnesses, such as depression and anxiety, and also to boost general brain functioning.
How can exercise give you mental health benefits that go deeper? Following are three mechanisms that explain these longer-term benefits.
1. Self-esteem and mastery explanations
There are a number of models that consider the relationship between participation in physical activity and self-esteem.
A pioneering model by Sonstroem back in 1978 was deemed to be reasonably successful in finding correlation between physical activity and psychological health, based on self-esteem assessments.
This model presents a useful cycle of feeling better: physical activity increases physical ability, which increases a person’s self-belief, which consequently boosts self-esteem. The model found that people with higher self-esteem take greater pride in their bodies, so they continue to exercise, thereby maintaining their feelings of wellbeing.
That’s a useful cycle.
2. Increased brain functioning
According to David Bucci, an associate professor at Dartmouth's Department of Psychological and BrainSciences, exercise also appears to improve learning and memory. Exercise has been shown to affect the Brain Derived Neurotrophic Factor (BDNF), which plays a role in the growth of children’s and adolescents’ brains. They discovered that BDNF expression in exercising rats was positively connected with improved memory.
Bucci states: "The implication is that exercising during development, as your brain is growing, is changing the brain in concert with normal developmental changes, resulting in more permanent wiring of the brain in support of things like learning and memory. It seems important to [exercise] early in life."
The Royal College of Psychiatrists backs this up, saying: “Exercise can stimulate chemicals in the brain called brain derived neurotropic factors. These help new brain cells to grow and develop.”
Additionally, they state there may be further benefits to the brain’s growth and development: “Exercise seems to reduce harmful changes in the brain caused by stress.”
3. The benefits of taking control
Sometimes, we just need to feel like there is one thing in the world we can control.
When we are struggling to cope with an overload of stressful external events, taking control of at least one thing in your life can be valuable. Exercise provides a great excuse to take time out do something for yourself, 100% under your own control. Having this degree of control can be very beneficial to your mental state.
The Royal College of Psychiatrists says that exercise can “Give you a sense of control over your life – that you have choices you can make. The sense that you are looking after yourself can also feel good.”
This is a genuine mental health benefit of exercise: a feeling of wellbeing from being in control and doing something healthy and meaningful.
Whilst the exact causes as to why exercise benefits mental health may not be reduced down to a simple cause-and-effect, there is clear evidence that there is a real link. And this is nothing new. Many studies that found links go back to the 1970s, and earlier.
Today, scientists and medical researchers continue to explore possible links and search for irrefutable scientific evidence.
Regardless of what the precise cause may be, it is true that exercise can make you feel better and emotionally. It doesn’t matter whether you know exactly what the cause is, or why it is happening. What matters is that there is a cause, there is a link, and you can receive benefits.
What matters is that you get out and get moving, and that you experience these benefits.
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Evidence of links between exercise and mental health
The Influence of Exercise on Mental Health, Daniel M. Landers, Regents’ Professor, Department of Kinesiology, Arizona State University http://www.fitness.gov/mentalhealth.htm
Physical Activity and Mental Health, The Royal College of Psychiatrists
The Exercise Effect, Kirsten Weir, American Psychological Association, December 2011 http://www.apa.org/monitor/2011/12/exercise.aspx
Depression and anxiety: Exercise eases symptoms, Mayo Clinic Staff http://www.mayoclinic.com/health/depression-and-exercise/MH00043