While most people appreciate the health advantages that come from running, cycling, or lifting weights, fewer people understand the benefits that come from a good swim, which include muscle toning and strengthening, reduced inflammation, and boosted heart, lung, and mental health.

As it turns out, propelling one’s body mass through water activates numerous systems throughout the body and makes the low-impact, high-results nature of the sport second to none. It also explains why Americans make more than 300 million recreational swimming visits a year, resulting in swimming being the fourth most popular recreational activity in the country, per data from the U.S. Centers for Disease Control and Prevention.

“Swimming provides an array of specific benefits such as improved cardiovascular and respiratory fitness, improved muscle strength and endurance, improved lean body mass, lower risk of traumatic injuries such as occurs during high-impact activities, and improved mental health and well-being,” says Mitch Lomax, a pulmonologist and exercise physiologist at the University of Portsmouth in the United Kingdom.

The sport has the added advantage of being available to people of all ages and among those with physical limitations – individuals for whom activities like running or cycling could be more challenging.

“Swimming is an activity that can be performed across the age and ability spectrum that exists in other sports,” says Lori Sherlock, an exercise physiology professor, Ironman challenger, and aquatic therapy coordinator at West Virginia University School of Medicine.