Any fitness freak who lives between the Midwest and Northeast knows that this winter has been unkind to outdoor types. For the most part, those of us who enjoy a run at the local park have been stuck at the gym running on a treadmill — that’s boring. So with the spring only moments away, many of us are itching to get out for a run or bike ride, but jumping straight into an outdoor workout can be harmful, experts say.

“The harsher the winter, the more we have to be careful not to come back too fast, too soon,” exercise physiologist and running coach Tom Holland told Reuters. “Even people who are generally fit might do less over the winter.”

Besides weather changes, which can take up to “two weeks to acclimate” to, Holland notes that running on a treadmill is much softer on the feet and the mechanics are different, as a runner’s foot bounces more on a treadmill than it would on pavement and the belt pulls their feet back. Similarly, people who do spin classes or cycling at the gym may shock their body when riding bikes on mountains or in the street.

Once the body’s lungs, heart, and muscles are adjusted to the warmer weather and outdoor terrain, exercise can become much more pleasurable. “The mind is constantly seeking variety,” Gregory Chertok, a sports psychology consultant with the American College of Sports Medicine, told Reuters. “On a treadmill, flat is guaranteed but outdoors you have to watch for potholes, puddles, and obstacles.” This awareness, in turn, can help improve balance and proprioception — the unconscious awareness of movement and spatial orientation — he added.

The benefits of exercising outdoors, however, extend beyond increased strength, balance, and awareness. Studies have shown that people who exercised outdoors did it for longer, while measuring higher with regards to vitality, enthusiasm, pleasure and self-esteem, and lower on tension, depression, and fatigue, The New York Times reported. Meanwhile, other studies have linked outdoor activity to optimism and self-control, and motivation and energy. Although these benefits were due, in part, to being outdoors, some researchers believe it’s actually the color green that’s responsible.

Yet, even with nicer weather, we still shouldn’t “eschew the gym,” Holland told Reuters. “Strength training is a big part of being injury-free.” For many, that means striking a balance between outdoor cardio exercises and indoor strength exercises. The Department of Health and Human Services’ Physical Activity Guidelines suggests that every adult get at least two-and-a-half hours of moderate-intensity physical activity each week, with at least another two days a week dedicated to strength training exercises. Doing so can reduce the risk of heart disease, type 2 diabetes, and depression, among many others diseases.