RESEARCH

Horticultural Therapy Reduces Biomarkers of Immunosenescence and Inflammaging in Community-Dwelling Older Adults: A Feasibility Pilot Randomized Controlled Trial

After 6 months, participants in the gardening group had significantly higher levels of naive CD8+ T cells and lower levels of CTLA4+ TEMRA cells, both markers of a stronger immune system.Additionally, they experienced a notable drop in IL-6 levels, which was strongly linked to the improved immune profile and lower signs of chronic inflammation.

Program Types: Therapeutic

Population Groups: Older Adults/Seniors

Setting or Context: Community Gardens, Natural Areas/Parks/Forest

Health and Wellness Outcomes: Improved Stress Management, Improved Cognitive Function, Improved Physical Health

Allied Profession Intersections: Recreational Therapy

Type of Activity: Indoor Plant Care, Outdoor Gardening, Growing Plants from Seed

Evidence Type: Peer-Reviewed Studies, Randomized Controlled Trials, Quantitative Research

Measurement and Evaluation: Standardized Assessment Tools, Program Effectiveness

Access: Free

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Summary

This study tested whether gardening and nature-based activities—known as horticultural therapy (HT)—could improve immune health in older adults. Researchers recruited 59 people aged 61–77 in Singapore and randomly assigned them to either a six-month HT program or a waitlist control group. The program included indoor and outdoor gardening, park visits, and nature education. Blood samples were taken at the start, 3 months, and 6 months to measure immune cell changes and levels of IL-6, a chemical linked to inflammation and aging.

The group that participated in gardening activities showed improvements in their immune system, including an increase in healthy “naive” T cells and a decrease in exhausted T cells that are linked to chronic disease and aging. IL-6 levels also dropped, suggesting less inflammation in the body. These changes were not seen in the control group. The study highlights how simple nature-based activities may help older adults stay healthier and reduce the risk of age-related illnesses.

Link

Chua, M., Tan, J., Lee, S. et al. (2021). Horticultural therapy reduces biomarkers of immunosenescence and inflammaging in community-dwelling older adults: A feasibility pilot randomized controlled trial. J Gerontol A Biol Sci Med Sci., 76(2), 307-317

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