Taking A Nature Pill

People naturally gravitate toward nature. A picturesque landscape, a sunset’s spectacular array of colors, a sunny beach, crystal blue water, all capture our attention.

And whether we can describe just why nature makes us feel so good, we seem to know it does.

According to research done by Dr. Mary Carol Hunter, an Associate Professor at the University of Michigan, it also only takes twenty minutes. She explains, “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” (Hunter et al., 2019).

Using an 8-week study design, Hunter and her team asked participants to take a “nature pill” with a duration of 10 minutes or more, at least 3 times a week. Levels of cortisol, a stress hormone, were measured from saliva samples taken before and after a nature pill, once every two weeks.

As part of the study, 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. What participants were instructed to do was to take the nature pill in daylight, avoid combining it with exercise, and avoid the use of social media, internet, phone calls, conversations and reading – all factors known to influence stress.

Because participants were allowed to choose the amount of time they spent in nature – so long as it was more than ten minutes – Hunter and her team were able to identify the optimal duration of a nature pill. Further, the study design gave a realistic prediction of just how time in nature can be added to a regular daily schedule – and remain effective.

Hunter explains, “We 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” (Hunter et al., 2019).

What Hunter and her team found, however, should have us all rethinking our daily schedules. Just a twenty-minute nature experience was enough to significantly reduce cortisol levels; and to drop cortisol levels at their greatest rate, all that is needed is 20 to 30 minutes sitting or walking in nature (Hunter et al., 2019).

Breaking new ground by providing a qualitative measure of an effective nature dose, this study provides the first estimate of how nature experiences impact stress levels in the context of normal daily life, and in doing so, offers an invaluable rule of thumb for healthcare practitioners: to reduce stress spend twenty minutes in nature; to reduce stress most effectively, spend twenty to thirty minutes in nature.

The hope, according to Hunter, is that not only will her work help guide nature pill prescriptions, but also shed some light on how we might design cities and communities for better mental health.