2. Enjoy moments of awe.

Much like the sighting of a cardinal, there are many things we experience when running outside that make us feel good. Flowers blooming along a trail, a misty waterfall (if you're lucky enough to live in an area with waterfalls!), a beautiful bird swooping down, a big buck standing up ahead on the trail.

This idea can be referred to as awe. Awe is often reserved for big moments like seeing a huge double rainbow across the sky or looking at the Grand Canyon for the first time. Awe can also be experienced through what I'll refer to as "micro-moments," and there are many opportunities for these moments while out on a run in nature. These moments are also scientifically beneficial to humans.

"Even brief experiences of awe yield a host of benefits including an expanded sense of time and enhanced feelings of generosity, well-being, and humility," according to a study from UC San Francisco. Additional research from UC Berkeley found that regularly experiencing awe can likely help with inflammation levels (something many of us runners can benefit from).

Physical health benefits of running outside

3. Soak up some vitamin D

Vitamin D is one of our body's most critical nutrient needs, helping us in a multitude of ways from bone density to immune health. Despite this fact, roughly 35% of Americans are vitamin D-deficient, according to the Cleveland Clinic.

One of the best ways to get your vitamin D levels up is direct sunlight absorbed through your skin. What better way to do so than on a run on your local trails while breathing in the fresh air? Next time you're out running and the sun is shining, just think of nature giving you a metaphorical IV drip of a life-sustaining nutrient. Pretty cool, huh?

4. Enhance your overall fitness.

In almost any system on earth, whether the human body, society, or your backyard garden, diversity creates more resilience and strength. Running outside offers more diversity of terrain and stimulus from jumping over cracks and puddles, turning the corner, running up and down hills or stairs, avoiding roots in the trail, and more. In turn, more is demanded from your body relative to running on a treadmill, paved road, or a track.

For example, your core is more engaged when you're turning a corner or a trail switchback, your quads are more engaged when you're running downhill, and your calves are more engaged when jumping over a curb or running uphill. Running on a treadmill (while still a great physical workout) limits the number of muscles you engage relative to running outside. The stronger your entire body is, the more resilient and more efficient it becomes. In addition, the more you bound down the trail avoiding roots or rocks, the more you develop a better sense of balance.

5. Improve your knee and back health.

This one, I know, can be difficult to believe. Many of us runners have likely been told, "Your knees are going to be shot by the time you're 50!" Yet a study from The Journal of Bone and Joint Surgery comparing 675 runners concluded that the arthritis rate of marathon runners was well below that of the average American. When running on trails outside, the softer surface is more gentle on your knees, hips, and back than concrete or a treadmill.

6. Increase your lifespan

A 2018 meta-analysis published in the British Journal of Sports Medicine concluded that running participation is associated with 27%, 30%, and 23% lower risk of all-cause, cardiovascular, and cancer mortality, respectively, compared with no running. That's quite a big difference and a seriously good reason to get outside every week.

Mental health benefits of running outside

7. Decrease depression.

Simply put, running helps combat depression. This probably doesn't come as a surprise to most, as I think any runner reading this would agree that running helps to keep your stress and anxiety balanced and ward off depression. Running outside adds another layer of mental health to the equation. When running outside, you're breathing in fresh air, running as the sun is rising or setting, maybe feeling the wind at your back or the chill of an early morning.

We, as humans, have evolved over a long time in a symbiotic relationship with nature. It likely just feels, well, "natural" and refreshing to most. Running outside allows you to explore new areas and new trails and see, hear, smell, and feel new things. You're likely passing by people and locking eyes, maybe even smiling. That moment with other people, especially while in nature, has much deeper-reaching mental and physical benefits than one likely realizes.