Physical Activity Positively Impacts Symptoms of Depression, Anxiety

What is Dopamine?

Dopamine is a neurotransmitter associated with memory and motivation and is easily generated as a response to social media. However, despite this prevalence, depression and other mental health concerns are more widespread than ever. On the surface, one may assume that an increase in accessibility of dopamine, which plays a role in the brain’s reward system, would improve mood and mental health, but it appears to do the opposite.

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In her book Dopamine Nation: Finding Balance in the Age of Indulgence, Anna Lembke, MD, discusses the dangers of dopamine overload and its impact on mental health, discipline, and determination.¹ Modern society has put individuals at an unprecedented and increased risk of dopamine overload. An excess in pleasure, usually generated from artificial means such as social media, seems to tip the balance between pleasure and pain, causing imbalance in expectations.¹ When an individual experiences dopamine overload, or a pleasurable stimulus repeatedly, the stimulus effects that the individual experiences decrease. Over time, the threshold for pleasure increases while the vulnerability to pain also increases, which affects tolerance. The chronic use of drugs also decreases dopamine D2 receptors and decreases dopamine release, thus diminishing reward circuit sensitivity in the brain. As a result, it is difficult to experience pleasure after prolonged exposure.¹

When mindlessly scrolling with “free” dopamine, the pursuit of pleasure is uninhibited. Lembke writes “the paradox is that hedonism, the pursuit of pleasure for its own sake, leads to anhedonia, which is the inability to enjoy pleasure of any kind.”¹ In order to combat the consequences of anhedonia, one must manually engage in difficult tasks. Free dopamine in young adults is seemingly limitless as a response to social media and electronic use. These unlimited sources of dopamine are associated with sedentary lifestyles, which increase the lack of balance of pain and reward, making this population at high risk of this kind of lifestyle, resulting in poorer outcomes from mental health. Because of time at college or in a career, the number of hours spent sitting increases annually. There are significant relationships between sedentary lifestyles and negative physical and mental health outcomes.² One way to engage the pain side of the pleasure-pain balance is through physical activity.

Mental Health and Physical Activity Among Students

University students and young professionals report high levels of stress and cognitive overload. Approximately 60% of university students met the criteria for 1 or more mental health disorders during the 2020-2021 academic year, according to a study of 373 universities across the nation.³ Mental health disorders may be attributed to numerous factors including, but not limited to, the COVID-19 pandemic and the associated isolation, sedentary lifestyle habits, and increased screen time without challenging stimulation. What kind of an impact can physical activity have on mental health?

A 16-week study conducted by the Amsterdam University Medical Centers partially randomized patients to receive either antidepressant medications (escitalopram or sertraline) or group-based running therapy (2 or more times per week). Investigators analyzed data from 141 patients who had a mean age of 38.2 years, with 45 receiving antidepressant interventions and 96 undergoing running therapy. According to the intention-to-treat analyses, remission rates at the end of the 16 weeks were comparable at 44.8% for pharmacotherapy and 43.3% for running.⁴

Patients in the running group also experienced improvements in weight, waist circumference, systolic and diastolic blood pressure, heart rate, and heart rate variability.⁴ Running therapy compared with antidepressant medications as a monotherapy resulted in a similar improvement to pharmacotherapy with additional health benefits. It is important to note that these results were statistically insignificant, which may be attributed to the small sample population.⁴

According to a meta-analysis of 49 studies, comprising over 250,000 individuals, patients who engage in physical activity are less likely to experience depression and anxiety. Furthermore, those who engage in physical activity are less likely to be diagnosed with anxiety disorders. Resistance training has been less studied than aerobic exercise, but overall, the data show that it reduces depressive symptoms, especially when used as an adjunct to therapy and other outpatient treatment approaches.⁵ Aerobic exercise has been shown to improve depressive symptoms at rates comparable to psychological and pharmacological interventions when compared with no treatment and when compared with standard control conditions. It is important to note that without consistency and continuation of physical activity, the positive effects of the training dwindles over time.⁵

There is evidence that supports the ability of aerobic exercise to improve mental and physical outcomes. To determine the impact of lower intensity compared with increased intensity, a double-blind, randomized control study was conducted over 6 months, in which 42 patients aged 18 to 60 years with depression, determined by the Hamilton Depression Rating Scale 17 (HDRS-17), were divided into a control group that received basic stretching activities and a group that received aerobic exercise as an intervention. Patients’ depression severity was measured using the HDRS-17 and the Beck Depression Inventory. It was found that both groups experienced short-term improvements in symptom severity with aerobic exercise resulting in greater improvements in mental fortitude.⁶ The use of physical activity, varying in extent, resulted in short-term improvement in the outcomes of patients with depression.

Sixty-one university students were studied during the academic year over the course of 6 weeks, with one group undergoing high-intensity interval training (HIIT); another undergoing moderate continuous training (MCT); and the other, used as the control, undergoing no exercise. Depression, anxiety, and perceived stress were tracked through tumor necrosis factor α (TNF-α), interleukin-6 (IL-6),IL-1β, and C-reactive protein. At the conclusion of the study, it was found that depression increased in students in the control group and MCT reduced depression and levels of TNF-α, a proinflammatory cytokine. Although HIIT decreased symptoms of depression, it increased perceived stress, TNF-α, and IL-6 levels when compared with MCT.⁷ Therefore, while physical activity demonstrated a reduction in depression among students, it is important to note that intensity of exercise is also important for prolonged health. The higher the intensity, the greater the risk of increased perceived stress and TNF-α and IL-6 levels.⁷

Data from 15 studies of children and adolescents aged 5 to 17 years with intellectual disabilities (IDs) were analyzed for the effects of physical activity on mental health, psychological health, and cognitive function. According to the meta-analysis, the patients with IDs experienced great improvement in mental health, moderate improvement in psychological health, and great improvement in cognitive functioning. Randomized controlled trial interventions also demonstrated the greatest benefits to the patients were derived from more than 2 hours per week of therapeutic and aerobic exercise.⁸

Although mental health disorders have been increasingly prevalent in recent years, it is evident that physical activity can help offset the challenges associated with symptoms of anxiety and depression, especially those caused by social media.

About the Author

Noni Theocharides is a PharmD student at the Rutgers Ernest Mario School of Pharmacy, in Piscataway, New Jersey. Noni founded a small business, Logos Solutions LLC, to provide medical education to other students.

References

1. Lembke A. Dopamine Nation: Finding Balance in the Age of Indulgence. Dutton; 2021.
2. Herbert C. Enhancing mental health, well-being and active lifestyles of university students by means of physical activity and exercise research programs. Front Public Health. 2022;10:849093. doi:10.3389/fpubh.2022.849093
3. Lipson SK, Zhou S, Abelson S, et al. Trends in college student mental health and help-seeking by race/ethnicity: findings from the national healthy minds study, 2013-2021. J Affective Disord. 2022;306:138-147. doi:10.1016/j.jad.2022.03.038
4. Verhoeven JE, Han LKM, Lever-van Milligen BA, et al. Antidepressants or running therapy: comparing effects on mental and physical health in patients with depression and anxiety disorders. J Affect Disord. 2023;329: 19-29. doi:10.1016/j.jad.2023.02.064
5. Smith PJ, Merwin RM. The role of exercise in management of mentalhealth disorders: an integrative review. Annu Rev Med. 2021;72:45-62.doi:10.1146/annurev-med-060619-022943
6. Imboden C, Gerber M, Beck J, Holsboer-Trachsler E, Pühse U, Hatzinger M. Aerobic exercise or stretching as add-on to inpatient treatment ofdepression: similar antidepressant effects on depressive symptoms and larger effects on working memory for aerobic exercise alone. J Affect Disord. 2020;276:866-876. doi:10.1016/j.jad.2020.07.052
7. Paolucci EM, Loukov D, Bowdish DME, Heisz JJ. Exercise reduces depression and inflammation but intensity matters. Biol Psychol. 2018;133:79-84. doi:10.1016/j.biopsycho.2018.01.015
8. Yang W, Liang X, Sit CH. Physical activity and mental health in children and adolescents with intellectual disabilities: a meta-analysis using the RE-AIM framework. Int J Behav Nutr Phys Act. 2022;19(1):80. doi:10.1186/s12966-022-01312-1