A new study  out of the University of Michigan claims that better health can be yours in just 20 minutes be day -- you just need to get up off your couch and step outside.

Study co-author MaryCarol Hunter told the Detroit Free Press that she and her colleagues were trying to lock down exactly how much time out doors is required in order to have a positive affect on people's stress levels, blood pressure, and more.

While doctors in Japan have been making such "nature pill" prescriptions for years, it wasn't clear exactly what patients should be doing -- until now.

She and her colleagues used field studies of volunteers, who put away their cellphones and got outside and did something, anything, in the great outdoors. The volunteer saw a demonstrable decrease in stress in 20 minutes -- and a "dramatic decrease" after another 10.

So while 30 minutes a day is "optimal," 20 minutes is sufficient to keep excessive stress at bay, though but Hunter says any time outdoors can help.

"Start with five minutes and see where it takes you," she said.