The effectiveness of one’s immune system generally declines with age, resulting in greater susceptibility to infection and chronic inflammation in later years. Researchers explored how horticultural therapy may slow this process and provide a boost to immune functioning.
Twenty-nine community-dwelling older adults participated in a series of horticultural activity sessions, while a control group of 30 older adults were put on a wait list. Each session started off with a five-minute stretching and breathing exercise before engaging in indoor horticultural activities, park visits, or outdoor gardening. The intervention consisted of 60-minute weekly sessions for the first three months, then one session per month in months 4 through 6. The average age in both groups was 67 years (range 61 to 77) and all participants were in good physical and cognitive health. Blood samples were drawn from participants at baseline, three months, and six months as a measure of immune functioning.
The horticultural therapy group showed increased levels of naïve T cells at three and six months, compared to the control group. These naïve T cells are important for an effective immune response to new, unfamiliar pathogens. At six months, the horticultural therapy group also showed healthier memory T cells, which are important for warding off previously encountered pathogens. This group also had lower levels of inflammation after engaging in horticultural therapy.
Getting outdoors and connecting with nature has a range of benefits for our well-being, and this study added one more reason to cultivate one’s green thumb. The study took place over six months and the boost to immune functioning lasted at least that long. Whether this is due to interacting with nature specifically or due to a sense of enjoyment or purpose from this type of activity, horticultural therapy appears beneficial for older adults’ health.
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Wong GCL, Ng TKS, Lee JL et al. Horticultural therapy reduces biomarkers of immunosenescence and inflammaging in community-dwelling older adults: A feasibility pilot randomized controlled trial. The Journals of Gerontology: Series A (2020); Ahead of print.