Recently, I wrote an article about the discovery of what scientists are calling 'hope' molecules. They are substances that quite literally make you feel better physically, mentally, and emotionally. And because mental health is extremely important to the overall well-being of an individual, I thought it would be a good idea to expand on this topic to share some basic exercise recommendations on how to trigger the release of these 'hope' molecules.

Mental health disorders are among the foremost causes of the global health-related burden, with significant costs to both the individual and society in general⁽¹⁾. Evidence from just a few years ago in 2019 demonstrated that about 970 million individuals worldwide were affected by a mental health disorder⁽²⁾ and about 44% of people will experience a mental health disorder in their lifetime⁽³⁾.

The annual global financial burden of mental health disorders has been estimated at $2.5 trillion (USD), which is expected to increase to $6 trillion (USD) by 2030⁽⁴⁾. Depression is the leading cause of mental health-related disease burden⁽⁵⁾, while anxiety is the most predominant mental health disorder⁽²⁾.

'Currently, there are different clinical practice guidelines for treating mental health depending on the country.'

Some countries utilize psychotherapy or pharmacotherapy as the initial treatment with lifestyle approaches considered as ‘complementary alternative treatments’ where psychotherapy and pharmacotherapy are ‘ineffective or unacceptable’. In other countries, lifestyle management is recommended as the first-line treatment approach⁽⁶⁾, though in practice, pharmacotherapy is often provided first.

Despite the numerous studies completed demonstrating the positive effects of physical activity on depression, anxiety and psychological distress, it has not been widely adopted therapeutically.

Such variables as the difficulty of prescribing and monitoring physical activity in clinical settings as well as the huge number of studies that have no common standard of measurement have most likely hampered a wider clinical adoption⁽⁷⁾.

However, a very recent study set out to undertake the most comprehensive synthesis to date of evidence regarding the effects of all modes of physical activity on symptoms of depression, anxiety and psychological distress in adult populations⁽⁸⁾.

This is the first ever study to accumulate such an extensive base of evidence regarding the effects of physical activity on depression, anxiety and psychological distress. After utilizing stringent inclusion criteria, this comprehensive systematic review identified 97 reviews, reporting the findings of 1039 unique randomized controlled trials, involving 128,119 participants.

Major findings of this study

Not surprisingly, findings indicate that physical activity interventions are effective in improving symptoms of depression and anxiety. The greatest benefits were seen in people with depression, pregnant and postpartum women, apparently healthy people, and individuals diagnosed with HIV or kidney disease.

All modes of physical activity were effective, and higher intensity exercise was associated with greater improvements for depression and anxiety.

Longer duration interventions had smaller effects compared with short and mid-duration, though the longest duration interventions still had positive effects.

The greatest improvements were seen in clinical populations which may reflect that these groups experience above-average symptoms of depression and anxiety and have low physical activity levels, which creates a potential for a greater degree of improvement compared with non-clinical populations⁽⁹⁾.

All modes of physical activity were valuable, including aerobic, resistance, mixed-mode exercise and yoga.

It is likely that the beneficial effects of physical activity on depression and anxiety are due to a combination of various psychological, neurophysiological and social mechanisms⁽¹⁰⁾.

Interestingly, different modes of physical activity stimulate different physiological and psychosocial effects. 

Resistance exercise had the greatest effect on depression, while yoga and other mind-body exercises were most effective for reducing anxiety⁽⁸⁾.

Another crucial finding was that moderate and high-intensity exercise was more effective than lower intensities.

The mechanisms involved in enhancing depression from physical activity are:

• - Increased expression of neurotrophic factors
• - Increased availability of serotonin and norepinephrine
• - Regulation of hypothalamic-pituitary-adrenal axis activity and reduced systemic inflammation⁽¹¹⁾.

Hence, lower intense activity may not be adequate for stimulating the neurological and hormonal changes associated with larger improvements in depression and anxiety. These findings further corroborate public health guidelines, which recommend multimodal, moderate, and vigorous intensity physical activity.

An additional mechanism of action may be in the release of myokines, which are essentially all-natural antidepressants that reduce stress, improve mood and learning and enhance brain function.

Myokines are released from skeletal muscle and are referred to as “in-house guardians” of mental and physical well-being⁽¹²⁾.

This was an extremely strong study given that it was the first umbrella review to evaluate all types of physical activity on depression, anxiety, and psychological distress in all adult populations. Only the highest level of evidence (i.e., meta-analyses of randomized controlled trials) were utilized and stringent measures were applied to inclusion criteria.

Clinical implications

• - Physical activity is valuable for managing symptoms of depression and anxiety across numerous populations.
• - Although it may be recognized, the benefit of exercise for managing depression and anxiety is often overlooked.
• - It is evident that many people with depression and anxiety have comorbidities (e.g., diabetes, heart conditions) and physical activity is beneficial for their mental health and disease management.
• - The above facts underscore the need for physical activity to be a mainstay approach for managing depression and anxiety.
• - All modes of physical activity are effective, with moderate-to-high intensities more effective than low intensity.
• - Shorter interventions of physical activity create larger benefits, which has health service delivery cost implications–suggesting that benefits can be obtained following short-term interventions, and intensive long-term interventions are not necessarily required to achieve therapeutic benefit.
• - The effect size reductions in symptoms of depression and anxiety are comparable to or slightly greater than the effects observed for psychotherapy and pharmacotherapy.

Future research to understand the relative effectiveness of physical activity compared with (and in combination with) other treatments is needed to corroborate these findings.

Summary

It is clear from the evidence to date that physical activity is extremely effective for improving depression and anxiety across a very wide range of populations. All modes of physical activity are effective, and higher intensity is associated with greater benefit.

The evidence indicates that it does not take much for exercise to make a positive change to an individual’s mental health. There is a need in clinical realms to include structured exercise interventions, as a mainstay approach for managing depression and anxiety.

It's no secret that exercise makes you feel better, the key is to do it every day to some degree.

Whether it's a 10 minute walk, 20-minutes of rowing, or a two hour iron slinging session in the gym, just do it, because you'll feel better when you do!

For those days you need a little extra motivation to get going, STEEL has an incredible lineup of pre-workouts to choose from, and you can find everything you need by clicking the button below.

References:
1.    Santomauro DF, M.H.A., Shadid J., Global prevalence and burden of depressive and anxiety disorders in 204 countries and territories in 2020 due to the COVID-19 pandemic. . Lancet 2021. 398: p. 1700-12.
2.    Evaluation., I.f.H.M.a., Global health data exchange 2019. 2022.
3.    Statistics., A.B.o., National study of mental health and wellbeing, 2021-2011. 2022, Australian Government,.
4.    Marquez, P.V. and S. Saxena, Making Mental Health a Global Priority. Cerebrum, 2016. 2016.
5.    Patel, V., et al., Addressing the burden of mental, neurological, and substance use disorders: key messages from Disease Control Priorities, 3rd edition. Lancet, 2016. 387(10028): p. 1672-85.
6.    Malhi, G.S., et al., The 2020 Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders. Aust N Z J Psychiatry, 2021. 55(1): p. 7-117.
7.    Kvam, S., et al., Exercise as a treatment for depression: A meta-analysis. J Affect Disord, 2016. 202: p. 67-86.
8.    Singh, B., et al., Effectiveness of physical activity interventions for improving depression, anxiety and distress: an overview of systematic reviews. Br J Sports Med, 2023.
9.    Rebar, A.L., et al., A meta-meta-analysis of the effect of physical activity on depression and anxiety in non-clinical adult populations. Health Psychol Rev, 2015. 9(3): p. 366-78.
10.    Arent SM, W.A., Arent MA., The effects of exercise on anxiety and depression, in Handbook of Sport Psychology. 2020. p. 872-90.
11.    Gujral, S., et al., Exercise effects on depression: Possible neural mechanisms. Gen Hosp Psychiatry, 2017. 49: p. 2-10.
12.    Schnyder, S. and C. Handschin, Skeletal muscle as an endocrine organ: PGC-1alpha, myokines and exercise. Bone, 2015. 80: p. 115-125.