Impact Of Exercise Type, Duration, & Intensity On Depression In Older Adults: A Review

Exercise offers numerous benefits for individuals with depression, acting as a powerful natural antidepressant.

Regular physical activity stimulates the release of endorphins, serotonin, and other mood-enhancing neurotransmitters, which can alleviate depressive symptoms.

Exercise also improves sleep quality, reduces stress and anxiety, boosts self-esteem, and provides a sense of accomplishment.

Additionally, it can increase social interaction, especially through group activities, countering the isolation often associated with depression.

For older adults, exercise also helps maintain cognitive function and physical independence, further contributing to overall well-being and mental health.

Li, X., He, S., Liu, T., Zhang, X., Zhu, W., Wang, C., & Sun, Y. Impact of Exercise Type, Duration, and Intensity on Depressive Symptoms in Older Adults: A Systematic Review and Meta-Analysis. Frontiers in Psychology, 15, 1484172. https://doi.org/10.3389/fpsyg.2024.1484172

Key Points

• The primary methods of improving depressive symptoms in older adults through exercise include resistance training, group exercise programs, and moderate to high-intensity physical activity.
• Factors like exercise type, duration, and intensity significantly affect the improvement of depressive symptoms in older adults.
• This research has certain limitations such as a small number of included studies, limited sample size, and potential linguistic or cultural bias due to only including English and Chinese language studies.
• Exercise interventions for depression in older adults are universally relevant due to the global aging population and high prevalence of depression in this demographic.

Rationale

Depression is a common condition affecting approximately 3.8% of the global population, with a higher prevalence of 5.7% among adults aged 60 and above (WHO, 2023).

As the world’s population ages, with projections indicating an increase in the 60+ age group from 1 billion to 1.4 billion by 2030 (World Health Organization, n.d.), geriatric depression is emerging as a significant public health concern.

In China, which is experiencing rapid population aging, survey data indicates that 33.1% of adults aged 60 and above exhibit depressive symptoms.

Geriatric depression is characterized by high occurrence rates, elevated suicide risk, and low recognition and consultation rates.

Its management is particularly challenging due to older adults’ poor tolerance of pharmacotherapy and the frequent co-occurrence of chronic illnesses (Dwyer et al., 2020).

Given the prevalence and treatment costs associated with mental health disorders in older adults, exercise has gained attention as a viable complementary or alternative strategy in depression management (Pedersen & Saltin, 2015).

Physical exercise has been widely recommended for treating depression due to its positive effects on mood, anxiety, and overall physical and psychological well-being (Stanton & Reaburn, 2014; Ravindran et al., 2018).

Previous studies have demonstrated that physical exercise can help alleviate mild to moderate depression, anxiety, and panic disorder (Brosse et al., 2002).

A review by Cooney et al. (2013) suggested that physical exercise has a positive impact on depression. Additionally, exercise may improve perceived functioning and reduce the social burden (cost of social support) in older adults (Fox et al., 2007).

While numerous studies have explored the effects of physical exercise on depressive symptoms in older adults, there is considerable variation in the specific exercise modalities, outcome measures, and experimental designs used across studies.

This systematic review and meta-analysis aims to comprehensively assess the existing research on the impact of physical exercise on depressive symptoms in older adults, considering a wide range of outcome indicators and exercise modalities.

Method

This systematic review and meta-analysis adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and the Cochrane Handbook for Systematic Reviews of Interventions.

The study was registered with PROSPERO (International prospective register of systematic reviews) under the registration number CRD42023405525.

Search strategy and terms

The researchers conducted a comprehensive search of published studies examining the relationship between physical exercise and depressive symptoms in older adults.

The following databases were searched: Cochrane Library, Web of Science, PubMed, Embase, CNKI, and Wanfang. The search included studies available until January 7, 2024.

English search terms used were “exercise,” “older adults,” and “depression,” while Chinese search terms were “physical exercise,” “older adults,” and “depression.”

The search was extended to grey literature sources, although no relevant results were found. References of included studies were also reviewed to ensure comprehensive coverage.

Inclusion and exclusion criteria

Inclusion criteria:

1. Randomized controlled trials (RCTs)
2. Participants: healthy older adults aged over 60 years
3. No significant differences between experimental and control groups before intervention
4. Experimental intervention involving physical exercise; control group not participating in regular exercise
5. Outcome indicators including validated depression scales (e.g., GDS, SCL-90, GDS-15, SGDS-K, TDQ, TGDS)
6. Data reported as mean ± standard deviation (M ± SD)
7. Articles in Chinese or English languages

Exclusion criteria:

1. Older adults with comorbidities or below 60 years of age
2. Interventions beyond exercise
3. Studies with incomplete data or lacking a control group

Statistical measures

The meta-analysis was conducted using Review Manager 5.3 and Stata 16.0 software.

Standardized mean difference (SMD) and 95% confidence intervals (95% CI) were used as effect sizes for continuous variables.

Heterogeneity was assessed using the I2 statistic, with a fixed-effects model applied when I2 < 50% and a random-effects model when I2 ≥ 50%.

Subgroup and sensitivity analyses were conducted to investigate potential sources of heterogeneity.

Publication bias was evaluated using Egger’s test and funnel plots, with a p-value threshold of <0.10 indicating potential bias.

Results

The systematic review identified 20 studies from 15 articles, involving a total of 1,346 participants (689 in control groups, 657 in experimental groups).

The meta-analysis revealed that physical exercise significantly improved depressive symptoms in older adults compared to control groups [SMD = -0.82, 95% CI (-1.19, -0.45)].

Subgroup analyses were conducted to explore the effects of exercise intervention time, physical exercise intensity, and exercise type on depressive symptoms:

1. Exercise intervention time:
   • 3-month intervention: SMD = -0.81, 95% CI (-1.38, -0.23)
   • 6-month intervention: SMD = -0.93, 95% CI (-1.46, -0.41) Both durations showed significant improvements, with 6-month interventions demonstrating slightly better results.
2. Physical exercise intensity:
   • Moderate intensity: SMD = -0.25, 95% CI (-0.47, -0.03)
   • High intensity: SMD = -0.94, 95% CI (-1.37, -0.51) Both moderate and high-intensity exercise showed significant improvements, with high-intensity exercise demonstrating a larger effect.
3. Exercise type:
   • Resistance exercise: SMD = -0.70, 95% CI (-1.20, -0.20)
   • Group exercise: SMD = -0.97, 95% CI (-1.89, -0.05) Both resistance and group exercises showed significant improvements in depressive symptoms.

The study did not find significant effects for aerobic exercise or yoga in improving depressive symptoms in older adults.

Sensitivity analysis identified one study (Lyu, 2012) as a potential source of significant heterogeneity. Egger’s test (p = 0.731) showed no significant publication bias.

Insight

This systematic review and meta-analysis provides robust evidence that physical exercise can significantly improve depressive symptoms in older adults.

The findings extend previous research by offering a more nuanced understanding of how different exercise modalities, intensities, and durations impact depressive symptoms in this population.

Key insights include:

1. Resistance exercise and group exercise appear to be particularly effective in alleviating depressive symptoms in older adults. This may be due to the combined benefits of physical exertion and social interaction provided by these exercise types.
2. Moderate to high-intensity physical exercise shows greater effectiveness compared to low-intensity exercise. This suggests that challenging older adults within their physical capabilities may yield better mental health outcomes.
3. Longer intervention periods (6 months) tend to produce better results than shorter ones (3 months), indicating the importance of sustained exercise programs for maximum benefit.
4. The study did not find significant effects for aerobic exercise or yoga, which contrasts with some previous research. This highlights the need for further investigation into the specific mechanisms by which different exercise types affect depressive symptoms in older adults.
5. The effectiveness of group exercise underscores the importance of social interaction in mental health interventions for older adults. This aligns with previous research suggesting that social support and participation can reduce depression risk in this population.

These findings extend previous research by providing a more comprehensive analysis of exercise interventions for depression in older adults, considering multiple variables such as exercise type, intensity, and duration.

The results suggest that tailored exercise programs, particularly those incorporating resistance training and group activities, may be more effective than general recommendations for increased physical activity.

Further research could explore:

1. The long-term sustainability of exercise interventions and their effects on depressive symptoms beyond the 6-month period.
2. The potential synergistic effects of combining different exercise types (e.g., resistance training with aerobic exercise).
3. The role of nutrition and sleep quality in moderating the relationship between exercise and depressive symptoms in older adults.
4. The neurobiological mechanisms underlying the antidepressant effects of different exercise modalities in older adults.
5. The impact of cultural factors on the effectiveness of exercise interventions for depression across different populations of older adults.

Strengths

The study had many methodological strengths including:

1. Adherence to PRISMA guidelines and Cochrane Handbook for Systematic Reviews, ensuring a rigorous and transparent review process.
2. Registration with PROSPERO, enhancing the study’s credibility and reducing potential bias.
3. Comprehensive search strategy across multiple databases in both English and Chinese, increasing the likelihood of capturing relevant studies.
4. Inclusion of only randomized controlled trials (RCTs), providing high-quality evidence.
5. Use of validated depression scales as outcome measures, ensuring reliability of the reported effects.
6. Conduct of subgroup analyses to explore the effects of different exercise parameters (type, intensity, duration), offering nuanced insights.
7. Assessment of publication bias and sensitivity analysis to evaluate the robustness of findings.
8. Consideration of multiple exercise modalities, allowing for comparison of their relative effectiveness.

Limitations

The study had several limitations that should be considered when interpreting the results:

1. Small number of included studies (20) and limited sample size (1,346 participants), which may affect the generalizability of findings.
2. Potential linguistic or cultural bias due to inclusion of only English and Chinese language studies, possibly overlooking relevant research in other languages.
3. Focus on intervention times of 3 and 6 months, limiting insights into the long-term effects of exercise on depressive symptoms.
4. Lack of analysis of gender differences in response to exercise interventions, which could be an important factor given potential physiological and psychological differences between older men and women.
5. Absence of consideration for socioeconomic factors such as income, marital status, and chronic illness, which may influence both exercise participation and depression in older adults.
6. Use of different tools to measure depressive symptoms across studies, which may affect the comparability and interpretability of results.
7. Limited exploration of the interactive effects of lifestyle factors such as sleep and nutrition alongside exercise interventions.
8. Potential for overestimation of effect sizes due to publication bias, despite efforts to assess and mitigate this issue.

These limitations suggest caution in generalizing the results and highlight areas for future research to address these gaps and strengthen the evidence base.

Implications

The findings of this systematic review and meta-analysis have several significant implications for clinical practice, public health policy, and future research:

1. Clinical Practice: The results suggest that healthcare providers should consider prescribing structured exercise programs, particularly resistance training and group exercises, as part of depression management for older adults. The effectiveness of moderate to high-intensity exercise indicates that clinicians should encourage older adults to engage in more challenging physical activities within their capabilities, rather than only recommending light exercise.
2. Public Health Policy: Given the demonstrated benefits of group exercise, policymakers should prioritize the development and funding of community-based exercise programs for older adults. This could include creating age-friendly public spaces and facilities that encourage physical activity and social interaction.
3. Mental Health Interventions: The study underscores the importance of integrating physical exercise into mental health interventions for older adults. Mental health professionals should collaborate with exercise specialists to develop comprehensive treatment plans that incorporate appropriate physical activities.
4. Long-term Care: For long-term care facilities and retirement communities, implementing regular group exercise programs could significantly benefit residents’ mental health and overall well-being.
5. Prevention Strategies: The findings support the use of exercise as a preventive measure against depression in older adults. Public health campaigns should emphasize the mental health benefits of regular physical activity for this demographic.
6. Personalized Interventions: The varied effectiveness of different exercise types and intensities suggests the need for personalized exercise prescriptions based on individual preferences, capabilities, and health status.
7. Research Directions: The study highlights the need for more research into the long-term effects of exercise on depression, the optimal combination of exercise types, and the role of sociocultural factors in exercise adherence and effectiveness among older adults.
8. Healthcare Education: Medical and allied health professional training should emphasize the importance of exercise in mental health management for older adults, ensuring that future healthcare providers are equipped to prescribe and support appropriate exercise interventions.
9. Economic Implications: By potentially reducing the need for pharmacological interventions and decreasing the overall burden of depression, exercise interventions could lead to significant cost savings in healthcare systems.
10. Quality of Life: Beyond alleviating depressive symptoms, the implementation of exercise programs for older adults could improve overall quality of life, physical health, and social connectedness, contributing to healthy aging on multiple levels.

These implications underscore the potential of exercise as a cost-effective, non-pharmacological approach to managing and preventing depression in older adults, with wide-ranging benefits for individuals, healthcare systems, and society at large.

References

Primary reference

Li, X., He, S., Liu, T., Zhang, X., Zhu, W., Wang, C., & Sun, Y. Impact of Exercise Type, Duration, and Intensity on Depressive Symptoms in Older Adults: A Systematic Review and Meta-Analysis. Frontiers in Psychology, 15, 1484172. https://doi.org/10.3389/fpsyg.2024.1484172

Other references

Brosse, A. L., Sheets, E. S., Lett, H. S., & Blumenthal, J. A. (2002). Exercise and the treatment of clinical depression in adults: recent findings and future directions. Sports medicine, 32, 741-760. https://doi.org/10.2165/00007256-200232120-00001

Cooney, G. M., Dwan, K., Greig, C. A., Lawlor, D. A., Rimer, J., Waugh, F. R., … & Mead, G. E. (2013). Exercise for depression. Cochrane database of systematic reviews, (9). https://doi.org/10.1002/14651858.CD004366.pub6

Dwyer, J. B., Aftab, A., Radhakrishnan, R., Widge, A., Rodriguez, C. I., Carpenter, L. L., … & APA Council of Research Task Force on Novel Biomarkers and Treatments. (2020). Hormonal treatments for major depressive disorder: state of the art. American Journal of Psychiatry, 177(8), 686-705. https://doi.org/10.1176/appi.ajp.2020.19080848

Fox, K. R., Stathi, A., McKenna, J., & Davis, M. G. (2007). Physical activity and mental well-being in older people participating in the Better Ageing Project. European journal of applied physiology, 100, 591-602. https://doi.org/10.1007/s00421-007-0392-0

Lyu, X. (2012). The impact of different types of physical exercise on the mental health of older adults. Chinese Journal of Gerontology, 32, 1020-1023.

Pedersen, B. K., & Saltin, B. (2015). Exercise as medicine–evidence for prescribing exercise as therapy in 26 different chronic diseases. Scandinavian journal of medicine & science in sports, 25, 1-72. https://doi.org/10.1111/sms.12581

Ravindran, A. V., Balneaves, L. G., Faulkner, G., Ortiz, A., McIntosh, D., Morehouse, R. L., … & Lam, R. W. (2018). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: Section 5. Complementary and alternative medicine treatments. The Canadian Journal of Psychiatry, 61(9), 576-587.

Stanton, R., & Reaburn, P. (2014). Exercise and the treatment of depression: a review of the exercise program variables. Journal of science and medicine in sport, 17(2), 177-182. https://doi.org/10.1016/j.jsams.2013.03.010

World Health Organization. (2023). Depression. https://www.who.int/news-room/fact-sheets/detail/depression

World Health Organization. (n.d.). Ageing and health. https://www.who.int/news-room/fact-sheets/detail/ageing-and-health

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