The walkers I passed looked deliriously happy despite foul weather the other day. They were probably sniggering at my jogging style, but research for the charity Mind has found that people do feel less depressed after a country walk.

A stroll in a park increased self-esteem in 90% of a group of people suffering from depression and 71% reported decreased levels of depression. After a walk through a shopping centre, 44% said their self-esteem had dropped and 22% felt more depressed.

More anti-depressant prescriptions than ever were issued in the UK last year. Mind wants the medical establishment to instead consider "ecotherapy", restoring health through contact with nature, such as exercise in a "green" settting, working on farms or structured contact with animals.

"It is a credible, clinically valid treatment option," says Mind's chief executive, Paul Farmer. "The debate needs to be broadened."

Scientific research is clear on the health benefits of nature. US scientists found that hospital patients with a view of greenery recover more quickly than those who can only see buildings. The UK government's chief medical officer said in a report that "physical activity is effective in the treatment of clinical depression and can be as successful as psychotherapy or medication."

More than 31m anti-depressant prescriptions were issued in the UK last year but the Royal College of GPs denies doctors prescribe them too readily.

Won't patients feel fobbed off if their GP tells them to get some exercise? Jules Pretty, professor of environment and society at Essex University, believes doctors could prescribe a structured daily "lifestyle plan". "Taking pills seems easier," he says, "but shouldn't we be thinking not just about 'silver bullet' solutions?"