Experts are now saying that taking twenty minutes to go on a walk can significantly lower your stress or hormone levels. This comes after researchers carried out a study on the most effective dose of an urban nature experience to counteract the effects of modern stress.

Because of this study, doctors will be able to prescribe “nature-pills” with the knowledge that they have a real measurable effect.

“We know that spending time in nature reduces stress, but until now it was unclear how much is enough, how often to do it, or even what kind of nature experience will benefit us,” said Dr. MaryCarol Hunter, an Associate Professor at the University of Michigan and lead author of the research. “Our study shows that for the greatest payoff, in terms of efficiently lowering levels of the stress hormone cortisol, you should spend 20 to 30 minutes sitting or walking in a place that provides you with a sense of nature.”

Nature pills are a lower cost option to reduce the negative health impacts stemming from growing urbanization and indoor lifestyles dominated by screen viewing. The study took place on an eight week period, and participants were asked to take a nature pill with a duration of 10 minutes or more, at least 3 times a week. Before and after each nature pill, levels of cortisol, a stress hormone, were measured from saliva samples taken. ‘

“Participants were free to choose the time of day, duration, and the place of their nature experience, which was defined as anywhere outside that in the opinion of the participant, made them feel like they’ve interacted with nature,” said Hunter. “There were a few constraints to minimize factors known to influence stress: take the nature pill in daylight, no aerobic exercise, and avoid the use of social media, internet, phone calls, conversations and reading.”

“Building personal flexibility into the experiment allowed us to identify the optimal duration of a nature pill, no matter when or where it is taken, and under the normal circumstances of modern life, with its unpredictability and hectic scheduling,” she continued. “We also accommodated day-to-day differences in a participant’s stress status by collecting four snapshots of cortisol change due to a nature pill. It also allowed us to identify and account for the impact of the ongoing, natural drop in cortisol level as the day goes on, making the estimate of effective duration more reliable.”

The researchers concluded that a 20-minute nature experience was enough to significantly reduce cortisol levels, and if you spent a little more time immersed in a nature experience, 20 to 30 minutes sitting or walking, cortisol levels dropped at their greatest rate.

“Healthcare practitioners can use our results as an evidence-based rule of thumb on what to put in a nature-pill prescription,” said Hunter. “It provides the first estimates of how nature experiences impact stress levels in the context of normal daily life. It breaks new ground by addressing some of the complexities of measuring an effective nature dose.”

She went on to say that she is hoping that this study will form the basis of further research in this area.

“Our experimental approach can be used as a tool to assess how age, gender, seasonality, physical ability and culture influences the effectiveness of nature experiences on well-being,” Hunter concluded. “This will allow customized nature pill prescriptions, as well as a deeper insight on how to design cities and wellbeing programs for the public.”