Exercise is not just good for the muscles; it is also one of the most effective tools to maintain brain health. Taking to Instagram on August 13, Dr Jeremy London, a board-certified heart surgeon, explained how exercise benefits the brain both in the short and the long term.Also Read | Worried that running will wear out your knees? Neurologist reveals 7 evidence-based ways to protect themHe called exercise “the most underappreciated antidepressant we have,” adding that something as simple and low-effort as a 20-minute walk can start providing the health benefits.“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 stated.Short-term benefits of 20-minute walksAccording to Dr London, the popular advice, “Go walk it off,” actually has a scientific basis, as walking can help clear the head and improve the mood. The short-term benefits that the heart surgeon listed for walking for 20 minutes include:Lowers circulating cortisol within one to two hoursShifts one out of the “fight or flight” modeInterrupts rumination, helps get out of a spiralMorning and midday sunlight exposure helps regulate circadian rhythm and moodLong-term benefits of 20-minute walksThe long-term benefits of brisk walking for 20 minutes every day, as per Dr London, include the following:25 percent lower risk of developing depression (even a 10-minute walk lowers the risk by 18 percent)Approximately 29 percent lower risk of developing an anxiety disorderUpregulates BDNF + IGF-1, supporting neuron growth while lowering long-term Alzheimer’s and Parkinson’s risk“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,” explained the surgeon.“You don’t need to be an athlete. Going from zero to something is where the biggest gains happen,” 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.”Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.This report is based on user-generated content from social media. HT.com has not independently verified the claims and does not endorse them.Dr Jeremy London is a board-certified cardiovascular surgeon with more than 25 years of experience. He has an MD from the Medical College of Georgia at Augusta University, and his focus is on the intersection of lifestyle, preventive medicine, and evidence-based longevity.