If you’ve started hitting the gym, you may have noticed a positive change in your mood and that’s no accident. Believe it or not, there’s some science backing your brain boost, and it may motivate you to keep up the good work — even on those sore days.

Multiple studies have shown that exercise, particularly running, is most likely to boost serotonin, a chemical that sends messages between nerve cells. Depression is often linked to a deficiency in serotonin, so finding a natural means of boosting production can work wonders for a person’s mental wellbeing.

Uniquely, however, your brain can tell the difference in how you feel about doing the exercise. Working out because you want to can create a different reaction inside the body than working out because you feel like you have to. Think of it like your body responding to basic instincts; running because you’re on a hunt (like our ancestors) feels different that running to escape danger. It’s like fight or flight, so going into your workout with the right mentality is critical. If you’re still working on getting into that positive perspective when it comes to working out, I recommend giving Planet Fitness a try. They offer a comfortable Judgement Free Zone where lasting, active lifestyles can be built. They offer a variety of high-quality cardio and strength equipment at each location, and most are open 24-7 to allow members to workout whenever works best in their schedules.

You’ve probably heard of the feel-good hormones that the brain releases in response to pain and stress — endorphins. They function to create a euphoric state of being following an intense fitness routine. For example, it’s common for some people to experience a “runner’s high” following a lengthy or challenging run. These endorphins help to create a positive outlook on life and diminish the perception of pain by acting as a sedative.

According to a 2015 report from the Alzheimer’s Association, “physical activity—even in some cases, mild physical activity such as walking—is associated with a decreased risk of cognitive impairment and/or improved cognitive function.” That same report goes on to conclude that “regular physical activity and management of cardiovascular risk factors (diabetes, obesity, smoking, and hypertension) have been shown to reduce the risk of cognitive decline and may reduce the risk of dementia.”

A reason for this is because new neuron creation is regulated by proteins, some of which are stimulated heavily by exercise. And most of those new neurons are located in the hippocampus — the section that handles memory and cognitive function. This means that a healthy exercise routine can be beneficial at just about any age.

Bottom line, work out because you want to; because you now know that it can have positive effects on your body inside and out. Your brain will thank you.