This article originally appeared on Time.com.
When the weather thaws, the plants bloom and the days get longer, it’s spring—and the best time of the year to take your fitness regimen outside. Here are six research-backed perks of al fresco exercise.
You work harder
When people exercise outside, they tend to spend more time doing it. One study found that older people who were active outdoors did at least 30 minutes more moderate-to-vigorous physical activity per week than those who only did it inside. It also made them feel healthier. “Nothing makes you feel more childlike than being outdoors,” says Dr. Pamela Peeke, a fellow of the American College of Sports Medicine and author of Fit to Live. “You’re modulating stress hormones, increasing endorphins and increasing the secretion of serotonin,” she says, so your mood brightens.
Being in nature lowers blood pressure
Spending time outside is also good for the heart. A recent study estimated that nearly 10% of people with high blood pressure could get their levels under control if they spent at least 30 minutes in a park each week, partly because of the heart-related benefits of getting fresh air and lowering stress. In Japan, public health experts recommend people spend time walking outdoors, a practice called forest bathing, or shinrin-yoku. Researchers in Japan have linked forest bathing with lower levels of the blood pressure-raising stress hormone, cortisol.
It spurs cancer-fighting cells
Some research suggests that when people are in nature, they inhale aromatic compounds from plants called phytoncides. These can increase their number of natural killer cells, a type of white blood cell that supports the immune system and is linked with a lower risk of cancer. These cells are also believed to be important in fighting infections and inflammation, a common marker of disease.
In one study, researchers found that people who took a long walk through a forest for two days in a row increased their natural killer cells by 50% and the activity of these cells by 56%. Those activity levels also remained 23% higher than usual for the month following those walks.
It can feel more fun
When people exercise outside, they feel better and enjoy the exercise more, studies suggest.“Enjoyment is an important pathway to the mental health impacts of physical activity,” says Rebecca Lovell, a research fellow at the University of Exeter in the UK. Exercising outside is also a great alternative for those who don’t want to go to the gym.
A review of research found that people who exercised outside reported feeling more revitalized, engaged and energized than those who did it indoors. The researchers also found that people who exercised outside felt less tension, anger and depression.
Your mental health may improve improve
Nature has a way of making people feel calm, and exercising outside can strengthen that effect. A small 2015 study found that people who walked for 90 minutes outside were less likely to ruminate on their problems and had less activity in the brain area linked to depression, compared to people who took similar walks but in urban areas. “Nature becomes a major distraction from all the stresses of life,” says Peeke.
You save money
Exercising outdoors is not only convenient, but it’s less expensive than a gym membership. It also cuts costs for the community. A recent study in England of “green exercises”—those done outside, including dog walking, running, horseback riding and mountain biking—estimated that the health benefits of doing physical activity in nature can save around $2.7 billion a year. “All you need is the right pair of shoes, and you can exercise on your own time,” says Peeke.