When it comes exercise, there’s an exercise more effective than weight training and running that you’re probably forgetting about — unless it’s the Olympics. Yes, we’re talking about that sport. The activity Michael Phelps has his name stamped on is actually the best exercise anyone can start.

Lap swims — done in a pool with designated lanes, if possible — is what we’re talking about. Swimming back and forth is nothing like being on the repetitive “dreadmill.” It’s more fun, carries a lot smaller chance of injury, and is essentially a life skill.

Plus, it’s the perfect way to cool off in the summer heat or get in an effective indoor workout during the snowy winter months.

“You can get any type of cardio workout that you need in the pool and have little or no impact on your joints,” explains Ian Rose, director of aquatics at East Bank Club in Chicago.

“If you have a good technique in your swim stroke, you can safely perform all of the cardio that any goal requires without doing damage to your body,” he explains. “Other exercises come with a list of potential long-term negative effects.”

The low-impact nature of the sport is one reason many athletes actually turn to swimming — or aqua jogging — when recovering from a running or cycling injury. Because of the effectiveness of the workout, athletes actually don’t miss out on any strength or endurance work they’d be getting in other sports.

“Swimming fires up more of your body’s major muscle groups than other forms of cardio exercise,” adds Natasha Van Der Merwe, director of triathlon at Austin Aquatics and Sports Academy in Austin, Texas. “Swimming not only engages your legs, but also recruits your upper body and core, especially your lats — the muscles of your middle back — and triceps,” she explains. Certain movements like dolphin kicks, flutter kicks, and more can help strengthen your core.

And your lungs also really benefit from this sport. In fact, a 2016 study notes that swimmers tend to have stronger lungs than other athletes.

But just because the sport benefits your lungs the most doesn’t mean it comes without warnings.

Another study cautioned that competitive swimmers who train indoors in chlorinated pools do risk lung changes that mirror the lungs of people with mild asthma. You can avoid these airway changes by training in outdoor pools and mixing up your training with other activities instead of relying only on swimming.

For those times you do choose the pool over the gym (let’s be honest, the machines can be a bit intimidating), the good news is that little gear other than a swimsuit and goggles are needed for a quality swim workout.

Should you wish, you can get more gear, like fins and a kickboard. They aren’t completely necessary, but serve as a training aid — especially as you learn proper form and technique.

If you’re looking to start swimming on your own, Van Der Merwe has provided a workout she regularly gives to beginners. She encourages swimming a short distance with a short rest to keep focus on technique in this simple workout.

The workout: Swim 20 x 50 yards (30-second rest between each)

Divide the 50 yards by focusing on four exercises each time or until you feel you have grasped the technique or focus before moving on to the next.

The number of calories you burn during a swim depends on how intense your workout is and how long you’re swimming for.

If you learned to swim as a kid or missed out on swimming lessons at an early age, working with a coach or swim group can be a great way to learn proper breathing and stroke techniques.

The freestyle stroke — demonstrated here by Van Der Merwe’s colleague at Austin Aquatics and Sports Academy, Missy Kuck — is the most common and best for beginners. You can also watch the video below.

Once you master that, a coach can teach you many other options to get you back and forth across the pool.

However, swimming is more than proper technique. Mapping out the purpose of each workout is just as important. Treat swim training as you would any other sport and go into each workout with a specific goal in mind.

This can be hard for beginners to do on their own, so Rose adds that this is where having a coach is beneficial. They can help all levels of swimmers build workouts to meet a specific goal and help you track progress along the way.

“There are very few cases where a swimmer would not benefit from working with a coach or swimming with a group,” Rose assures.

Ashley Lauretta is a freelance journalist based in Austin, Texas. She’s assistant editor for LAVA Magazine and contributing editor for Women’s Running. Additionally, her byline appears in The Atlantic, ELLE, Men’s Journal, espnW, GOOD Sports, and more. Find her online at ashleylauretta.com and on Twitter.