‘Most underappreciated antidepressant’: Doctor explains why a 20-minute walk matters

Regular physical activity is widely recognised for its benefits to cardiovascular and muscular health, but its effects on the brain and mental wellbeing are also increasingly being discussed. In an Instagram post, board-certified cardiovascular surgeon Dr Jeremy London described exercise as “the most underappreciated antidepressant we have,” and highlighted how even a relatively short walk may offer benefits.

Dr London said, “Remember, cardio training isn’t just for your heart. Resistance training isn’t just for your muscles. What’s good for your heart is also good for your brain. And exercise is one of the most powerful tools we have to protect and maintain our brain health.” He also pointed to the popular advice, “Go walk it off,” suggesting that a 20-minute walk may have both immediate and longer-term effects on mood and brain health.

According to Dr London, some short-term effects of a 20-minute walk include lowering circulating cortisol within one to two hours, helping the body move out of “fight or flight” mode, interrupting rumination, and helping people step out of a negative spiral. Morning and midday sunlight exposure while walking may also help regulate circadian rhythm and mood.

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.

For people who make walking a regular habit, Dr London cited several potential long-term benefits, including a 25 per cent lower risk of developing depression, with even a 10-minute walk associated with an 18 per cent lower risk. He also cited an approximately 29 per cent lower risk of developing an anxiety disorder, along with changes involving BDNF (Brain-Derived Neurotrophic Factor) and IGF-1 (Insulin-Like Growth Factor 1) that support neuron growth and may help lower long-term risks associated with conditions such as Alzheimer’s and Parkinson’s disease.

Explaining the role of BDNF, he said, “When you exercise, your brain increases something called brain-derived neurotrophic factor BDNF. Think of it like fertiliser. It improves the interconnection of brain cells, and it allows them to grow.”

At the same time, Dr London stressed that people do not need to be highly athletic to benefit from movement. “You don’t need to be an athlete. Going from zero to something is where the biggest gains happen,” he said. He added, “If you’re struggling with your mental health, movement helps — but it’s not a replacement for professional support when you need it. The days you feel the least like moving are usually the days you need it most. Not a hard workout. Not an hour. Just 20 minutes, outside, moving.”

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How does a brisk walk benefit the brain?

Dr Sanjeev Chaudhary, Chairman, Dept. of Cardiology, Marengo Asia Hospitals Gurugram, tells indianexpress.com, “A brisk walk increases heart rate, cardiac output and cerebral blood flow. The brain receives more oxygen and glucose, while exercise-related signals from muscle and other tissues influence the nervous system.”

There is also a shift in the stress-response system. Dr Chaudhary notes that exercise is itself a controlled physiological stressor: cortisol and adrenaline may rise transiently during activity, but regular exercise appears to improve regulation of the hypothalamic-pituitary-adrenal (HPA) axis and the ability to recover from stress. Exercise can also influence serotonin, dopamine and noradrenaline pathways involved in mood and motivation. “The subjective effect can be surprisingly immediate: a change of environment, rhythmic movement, sensory stimulation and attention away from repetitive thoughts can interrupt rumination,” states the expert.

How does walking help with depression and anxiety?

For depression, Dr Chaudhary says, the evidence is now quite strong. “A 2024 BMJ systematic review/network meta-analysis included 218 studies and more than 14,000 participants with depression. Walking or jogging was associated with a meaningful reduction in depressive symptoms, comparable in magnitude to several other forms of exercise.”

For anxiety, he says, the evidence is positive but somewhat less robust than for depression. Regular physical activity is nevertheless recommended as part of a healthy lifestyle, and WHO guidelines specifically recognise reductions in anxiety and depression symptoms.

Can regular walking reduce the risk of dementia?

For dementia and neurodegeneration, Dr Chaudhary notes that the evidence is encouraging but should be described carefully. A large meta-analysis found physical activity associated with approximately 20% lower risk of all-cause dementia and 14% lower risk of Alzheimer’s.

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Is 20 minutes of brisk walking enough to benefit the brain?

“Absolutely,” Dr Chaudhary shares, “This is perhaps the most important practical message.”

Twenty minutes of brisk walking is not the final target; it is an excellent entry point. “WHO explicitly recommends that inactive adults start with small amounts and gradually increase frequency, intensity and duration,” concludes Dr Chaudhary.

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.