Running Makes My Stress Melt Away, So I Asked a Doctor If There's Actually a Link

Cardio used to be the be-all, end-all of my fitness routine. Specifically, running. It wasn't until an injury sidelined me (turns out your knees don't love running five miles a day) that I found high-intensity interval training (HIIT), weight training, and swimming. Changing up my fitness routine helped me get the physical results I wanted and I eventually realized that I didn't actually have to run to maintain my fitness. Yet, there was one major reason why quitting altogether was never an option.

It has to do with mental health, namely stress relief and overall sanity. In terms of keeping me calm and relieving stress, nothing is more effective than running. That goes for the good runs, when my body is in perfect sync, nothing hurts, and my mind gets to wander without a care in the world, and the bad ones, when my Achilles starts pinging, my knees ache, my sides cramp, and I'm grumpy and unfocused. One is more enjoyable, but they both leave me noticeably calmer than when I started. They both make my problems seem smaller, more manageable, and less important.

Running is often touted as a way to relieve stress, and the deeper mental health benefits of cardio, and especially running, are just starting to be explored. One recent study, performed on mice, actually showed a possible connection between cardio and dementia prevention. But it's one thing to read about mental benefits and another to experience them for yourself. It's the ultimate brain hack. Really? All I have to do to feel better is go for a run?

According to Douglas Noordsy, MD, a sports psychologist at Stanford Health Care, it's based in biology. "People stimulate their brains in many ways when they're exercising," he told POPSUGAR. Exercise helps you increase blood flow to your brain, process more glucose, and even help create the connections between neurons that build memories. In terms of evolution, he explained, it's likely that early humans — primarily hunters and foragers — needed to run to hunt for food. Your brain's response to exercise, which includes improved spatial awareness and memory as well as social cognition, may have adapted from those survival needs. It's part of the reason why you feel sharper and more in tune after working out.

Exercise in general improves your brain health, Dr. Noordsy said, but there's something about running in particular that makes it different. "Running in a setting with less distractions, especially a natural setting, is a very contemplative activity," he said. The limitless headspace you enter during a good run is rejuvenating in a way most day-to-day activities just aren't. It's complete mental freedom, the ability to shift effortlessly from thought to thought.

What about running makes this happen? At a certain level of exertion, Dr. Noordsy explained, your brain's higher-level functioning will actually slow down in order to conserve energy. You can experience this for yourself: just try to solve a math problem while you're doing a hard cardio workout. "It doesn't go so well," Dr. Noordsy said. Sacrificing those more complex functions anchors you to the present moment.

But you don't have to be daydreaming on a run to reap mental benefits from it. Even if you're still thinking about problems in your life or at work, running helps your mind slow down and become "more open," as Dr. Noordsy described it. Going for a run can help you come up with ideas and solutions that you weren't getting when you were sitting at your desk.

Both cardio and strength workouts can help with stress and relaxation, Dr. Noordsy said. What sets apart running and other cardio exercises, like cycling and swimming, is their repetitive quality. If you're lifting weights or doing a HIIT workout, you're often focusing on your form, counting reps, thinking about this exercise or the next one. You don't have to focus on those technical aspects during a run, which makes it easier to relax and get into a rhythm.

Running outdoors in particular comes with its own set of stress-relief benefits. A recent study in the journal Frontiers found that just 20 minutes spent in nature can significantly lower your stress levels. A 2011 review from the University of Exeter concluded that exercising outdoors rather than indoors is linked with feelings of revitalization and energy, along with decreased tension, confusion, and anger. It's something I've experienced on my own runs: jogging along the waterfront or through a canyon leaves me with a serenity I don't get on runs through a city or suburban neighborhood, or on a treadmill.

The stress relief you can get from a run is real and backed by science and experts, but you have to feel it to believe it. It's the reason that running is still a part of my regular routine. I love the feeling of accomplishment following a hard strength-training workout or HIIT session, but nothing calms me down or puts my problems in perspective like a run. Even if running isn't your thing, going for a brisk walk or spending some time on the elliptical or the stationary cycle — any repetitive activity where your mind is free to wander — can do wonders for your mental health. It's my favorite form of self-care: a cleansing mind-body workout that leaves you feeling calm, collected, and ready to take on a fresh challenge.