Just 30 minutes of walking a day is enough to give people with depression more energy and confidence, new research has found.

It's been predicted that by 2030, depression will become the leading cause of what's known as disease burden - the impact of a disease or injury on the general population after treatment, rehabilitation or prevention efforts are made - in high-income countries. It's become alarmingly prevalent, affecting one in seven Australians and 40 million Americans. In America, anxiety disorders cost more than $42 billion a year, which is almost a third of the country's entire mental health bill, and according to the US National Institute of Mental Health, women are 70 percent more likely to be depressed at some point in their lives than men.

As with many physiological disorders, depression cannot be prevented or cured, and the effectiveness of current treatments can vary dramatically from one person to the next, so researchers are constantly trying to figure out ways - independent of antidepressant medications - to help patients mitigate the worst of the symptoms.

Having found in previous research that exercise and walking can improve the physical and emotional health of women who aren't depressed, Kristiann Heesch from the School of Public Health and Social Work at Queensland University of Technology (QUT), decided to investigate the effects on women who were. And Heesch's team wasn't just interested in linking physical activity to lessened symptoms of depression, they wanted to know, specifically, how much a person would need to do each day in order for it to be effective. 

The team analysed data collected from 1,904 women born between 1946 and 1951, who were surveyed over a seven-year period on their exercise habits, and their physical and mental health. Starting in 2001, all women reported having symptoms of mild to moderate depression, and they were surveyed up until 2010 to see how their condition developed over time.

Janice Neumann at Reuters reports that the women who averaged 150 minutes of moderate exercise - including golf, tennis, aerobics classes, swimming, or dancing - or 200 minutes of walking every week "had more energy, socialised more, felt better emotionally, and weren't as limited by their depression when researchers followed up after three years". While the physical benefits included being more fit and experiencing less pain, the researchers found that the psychological benefit of exercise for these women was more significant. 

"The good news is that while the most benefits require 150 minutes per week of moderate-intensity physical activity or 200 minutes of walking, even smaller amounts… can improve well-being," Heesch told Reuters.

Publishing their results in the American Journal of Preventive Medicine, the team said that the more physical activity a woman in her 50s or 60s with depression can do, the more benefits she'll get.

The finding might seem like common sense, Madhukar Trivedi, a professor of psychiatry from the Southwestern Medical Centre at the University of Texas in the US, who wan't involved in the study, told Reuters, but he said results like this are a great reminder to people that walking, as easy and innocuous as it is, is valuable, especially if you don't feel up to hitting the gym. "It does improve quality of life. That is not a new finding, but there remains skepticism in the culture that walking really does anything for depression or vitality - and this shows that it does," he says.

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Source: Scientific American