Exercise is  Preventive Medicine

Dwayne N. Jackson, PhD

What motivates you to train?

Is it aesthetics? Competition? Strength? Endurance? Injury rehab? Or something else?

Certainly, we all enjoy the aesthetic and performance improvements we reap with consistent training; but, we mustn’t overlook the science illustrating improvements in immunity,  inflammation, and neurochemistry we get from consistent training, good sleep hygiene, adequate recovery, and proper nutrition.

Exercise, without overtraining, stimulates cellular immunity, optimizes hormones and neurotransmitters, and reduces the risk of developing systemic inflammatory issues that affect our brain and body. This is why properly executed training, recovery, and nutrition can provide some protection from simple ailments like common colds and more complicated respiratory infections and viruses like SARS-CoV-2.

Since issues with immunity and inflammation underly many chronic diseases, then it should be no surprise that consistent physical activity also plays a monumental role in the prevention and treatment of such conditions.

Research over the past few decades tells us that, even if we are focused on our aesthetic and performance goals, our daily exercise regimen is also likely protecting us from (or treating) several serious chronic medical conditions including:

• Metabolic disorders (obesity, hyperlipidemia, type 1 & 2 diabetes, etc.)
• Cardiovascular issues (hypertension, heart disease, etc.)
• Pulmonary disease (COPD, asthma, etc.)
• Musculoskeletal problems (arthritis, osteoporosis, back pain, etc.)
• Neurological diseases (Alzheimer’s, dementia, Parkinson’s disease, multiple sclerosis)
• Mental health issues (stress, anxiety, depression, etc.)

Over the past several decades we have witnessed a worldwide decline in mental health. This coincides with increased cases of sedentary lifestyle and a recent surge in cases of chronic stress. As such, we have seen record-breaking reports of anxiety and depression around the globe. Poor mental health may promote and exacerbate many of the chronic medical conditions listed above. Thankfully, research aimed at understanding how exercise serves to buffer stress, anxiety, and depression has been fruitful.

Stress

We all experience daily stress, but chronic or traumatic stress can promote many health issues impacting the brain and body. Stress is very much a part of life and is not a disease in and of itself, however long-term chronic stress can lead to illness. Severe or chronic psychological stress can induce anxiety and depression, exacerbate diseases like asthma and rheumatoid arthritis, and promote inflammation, fat accumulation, and muscle loss.

Stress results in dysregulation of stress hormones like cortisol and catecholamines. High levels of catecholamines can lead to an increased blood pressure, while high levels of cortisol in chronic stress may contribute to changes in glucose and fat metabolism.

Overwhelming stress promotes unhealthy lifestyle choices like poor diet, tobacco use, recreational drug use, excessive alcohol consumption, and sedentary lifestyle. If you are stuck in this “loop”, the best way out is to increase activity and clean up your diet.

The stress-relieving benefits of regular exercise have a neurochemical basis:

• It promotes normal regulation of stress hormones adrenaline and cortisol.
• It stimulates the production of endorphins, neurochemicals released in the brain, which are natural painkillers and mood elevators. Endorphins are what promote the “runner’s high” and feelings of relaxation and optimism you feel after intense training sessions.

Regular exercise has emotional benefits:

If you are training for performance or aesthetics, as you get into better shape your self-image improves. This promotes a sense of discipline and control, which boosts overall self-confidence. The increase in self-confidence transfers to your daily work life and personal life and promotes stress resilience.

Anxiety

It’s likely that you, or someone you know, is currently dealing with anxiety. Anxiety disorders are the most common mental illness in the U.S., affecting 40 million adults in the United States age 18 and older. It’s not uncommon for someone with an anxiety disorder to also suffer from depression or vice versa. Nearly one-half of those diagnosed with depression are also diagnosed with an anxiety disorder.

The exact causes of anxiety are not clearly defined. However, in a basic sense, anxiety is often a result of the combination of biological vulnerability and experiencing stress during childhood or later in life. The severity of the anxiety may vary over time and spur-of-the-moment improvements can occur. Without treatment, many people experience long-term or chronic impairment. Studies show that regular exercise reduces and prevents symptoms of anxiety.

How regular exercise curbs anxiety:

• Intense training requires focus, which can distract you from things you are anxious about.
• As mentioned above, each exercise session optimizes brain chemistry. This promotes the release of potent anti-anxiety neurochemicals in the brain (e.g., serotonin, gamma-aminobutyric acid (GABA), brain-derived neutrophic factor (BDNF), and endocannabinoids.
• Exercise activates the frontal lobe of the brain, which is responsible for executive function (working memory, flexible thinking, and self-control). This keeps the brain’s amygdala from being ‘highjacked’ under stress, thereby protecting us from overreacting in anxiety-provoking situations.
• Consistent periodized training builds stress resilience so, over time, you experience less anxiety when experiencing stress.

Depression

Those who suffer from depression often also experience fatigue and the feeling that life is insurmountable, which can lead to physical inactivity, a loss of fitness, and thus increased fatigue. This loop is tough one to overcome, so depression is commonly treated medically with antidepressants and/or psychological therapy.

However, exercise studies report that those who suffer from depression and exercise regularly experience less depressive symptoms and decreases in depressive episodes. Research also suggests that low levels of fitness are more strongly associated with depressive symptoms than is one’s “aesthetics” or body composition.

How regular exercise helps with depression:

• Many people receive positive feedback from their environment and enjoy the social contact that exercise and/or their gym brings them.
• High-intensity exercise requires intense focus, which distracts you from intrusive thoughts and rumination.
• Regular training increases aerobic capacity and muscle strength, which improves physical well-being.
• Hormonal changes: increased beta-endorphins and optimized monoamines (adrenaline, noradrenaline, dopamine, serotonin, and melatonin)
• Exercise stimulates the growth of new nerve cells and release of proteins known to improve the survival of brain cells and improve brain health. One mechanism for this is through the exercise-induced increase in brain-derived neutrophic factor (BDNF).

So, there you have it, exercise IS medicine! What’s stopping you from getting your daily dose today? You just might need it tomorrow….

References

Nieman DC, Wentz LM. The compelling link between physical activity and the body’s defence system. J Sport Health Sci. 2019;8(3):201–217.

da Silveira MP, da Silva Fagundes KK, Bizuti MR, Starck É, Rossi RC, de Resende E Silva DT. Physical exercise as a tool to help the immune system against COVID-19: an integrative review of the current literature. Clin Exp Med. 2021 Feb;21(1):15-28. doi: 10.1007/s10238-020-00650-3. Epub 2020 Jul 29. PMID: 32728975; PMCID: PMC7387807.

Mynors-Wallis LM, Gath DH, Day A, Baker F. Randomised controlled trial of problem solving treatment, antidepressant medication, and combined treatment for major depression in primary care. BMJ 2000: 320: 26–30.

Booth FW, Roberts CK, Laye MJ. Lack of exercise is a major cause of chronic diseases. Compr Physiol 2012: 2: 1143–1211.

Pedersen BK, Saltin B. Exercise as medicine – evidence for prescribing exercise as therapy in 26 different chronic diseases. Scand J Med Sci Sports. 2015 Dec;25 Suppl 3:1-72. doi: 10.1111/sms.12581. PMID: 26606383.

https://adaa.org/understanding-anxiety/facts-statistics

https://www.acha.org/documents/ncha/NCHA-II_Fall_2018_Undergraduate_Reference_Group_Data_Report.pdf

Lago TR, Hsiung A, Leitner BP, Duckworth CJ, Balderston NL, Chen KY, Grillon C, Ernst M. Exercise modulates the interaction between cognition and anxiety in humans. Cogn Emot. 2019 Jun;33(4):863-870.

Brellenthin AG, Crombie KM, Hillard CJ, Koltyn KF. Endocannabinoid and Mood Responses to Exercise in Adults with Varying Activity Levels. Med Sci Sports Exerc. 2017 Aug;49(8):1688-1696. doi: 10.1249/MSS.0000000000001276. PMID: 28319590.

Schoenfeld TJ, Rada P, Pieruzzini PR, Hsueh B, Gould E. Physical exercise prevents stress-induced activation of granule neurons and enhances local inhibitory mechanisms in the dentate gyrus. J Neurosci. 2013 May 1;33(18):7770-7. doi: 10.1523/JNEUROSCI.5352-12.2013. PMID: 23637169; PMCID: PMC3865561.

Audiffren M, André N. The exercise-cognition relationship: A virtuous circle. J Sport Health Sci. 2019 Jul;8(4):339-347. doi: 10.1016/j.jshs.2019.03.001. Epub 2019 Mar 7. PMID: 31333886; PMCID: PMC6620209.