How many calories does swimming burn? This low-impact workout is a surprising one

Swimming might not be the first activity that comes to mind when you think of calorie-burning cardio. That spot is usually reserved for running, cycling, or gym workouts. However, a swimming workout can be an "underrated" way to burn calories and contribute to healthy weight loss.

"It's emerging as one of the most sustainable ways to burn calories and support whole-body wellbeing as it feels smooth and meditative, but it's also one of the most efficient ways to burn energy," says Emma Kuwertz-Norman, the national swim manager at Nuffield Health. "That whole-body engagement, combined with the water resistance, translates into meaningful calorie burn."

However, how many calories swimming burns is different for everyone, based on factors like age, weight, and activity levels outside the pool. With this in mind, we look closer at how many calories swimming could burn for you.  

How many calories does swimming burn?

Calorie burn is a highly individual calculation, based mainly on your current weight. Research by Harvard University suggests that in 30 minutes of general swimming: 

• Someone weighing 56kg (125lb) may burn 180 calories
• Someone weighing 70kg (155lb) may burn 216 calories
• Someone weighing 85kg (185lb) may burn 252 calories

Turning up the intensity by swimming faster or adding extra workouts, like Pilates for swimmers, will mean you burn more calories.

For example, the same Harvard research suggests that in 30 minutes of swimming laps around a pool "vigorously":

• Someone weighing 56kg (125lb) may burn 300 calories
• Someone weighing 70kg (55lb) may burn 360 calories
• Someone weighing 85kg (185lb) may burn 420 calories

If, like me, you sit between these weight figures, it may take a bit of guesswork to figure out where exactly you sit.

One way to understand how your body burns calories (without doing the maths yourself) is with one of the best fitness trackers. While no smartwatch is entirely accurate in tracking calorie burn, it'll put you in the right ballpark.

Several factors determine how many calories you burn swimming, though, explains Amanda Pace, a certified personal trainer, coach, and the founder of Sculptrition.

Factors that play into how many calories you'll burn swimming

• The intensity of your swim: As noted, swimming vigorously burns more calories than leisurely swimming. "The more effort you put into your swim, the more calories you are likely to burn," says Place.
• Body weight: The role your current body weight plays in how efficiently you burn calories shouldn't be undervalued either, says the trainer. "Generally, a heavier person burns more calories than a lighter person when performing the same activity because it requires more energy to move a larger body mass."
• Swim stroke: "Different strokes require varying levels of effort and engage different muscle groups. For instance, an intense freestyle or butterfly stroke tends to burn more calories than a relaxed breaststroke or backstroke," she says.
• Technique: "Efficiency in your technique, including proper body alignment, stroke mechanics, and breathing, can also affect the overall energy expenditure during swimming."
• Duration: Swimming for longer (even at a slower pace) will eventually burn more calories. If you're looking to burn more calories in a limited time, you'll need to increase the intensity of your swimming.
• Individual factors: Ultimately, how quickly someone will burn calories comes down to some very individual factors, some of which are outside our control. "Each individual's metabolic rate and fitness level can impact the calorie burn during swimming," says Place. "Metabolic rate refers to the rate at which your body burns calories at rest. Individuals with higher metabolic rates tend to burn more calories in general, including during exercise. Fitness level also influences the efficiency of your body's energy utilisation and can impact the intensity you can swim."

How to burn more calories swimming

Increase the intensity

If you know how many calories swimming burns for you and you want to increase it, upping the intensity of your workout is a good way forward.

"You can achieve this by incorporating interval training or high-intensity bursts into your swimming routine," explains Place. "I'd suggest alternating between faster, more vigorous swimming and active recovery or slower-paced laps of moderate intensity exercise. This interval-style training can elevate your heart rate and maximise calorie expenditure."

Do different strokes

"Varying your swim strokes can engage different muscle groups and increase the overall energy expenditure," says Place. "Each swimming stroke has its own demands and challenges, so incorporating a mix of strokes like freestyle, backstroke, breaststroke, and butterfly can provide a more comprehensive workout."

Switching up between the different swim strokes can also help prevent one muscle group from tiring out too quickly, keeping your body engaged, and increasing your calorie burn.

Add in some extra exercises

Water jogging, treading water, and strength training exercises like lifting water dumbbells can challenge the muscles even more and increase the intensity, says Place. "They provide more resistance, making your body work harder and burn more calories."

Just make sure you don't do so many exercises that you feel exhausted and lose your technique, the trainer says. "Focus on maintaining good body alignment, engaging core muscles, and employing proper stroke mechanics. This allows you to move through the water with less drag and greater efficiency, enabling you to swim faster and expend more energy," she says.

Swim for longer

If you needed an excuse to spend more time in the pool, this is it. Swimming every day or every couple of days will burn more calories than swimming just a few times a month. Also, the longer you swim, the more calories you'll burn.

"Gradually increase the length of your swim workouts as your fitness level improves," suggests the trainer. "Aim to swim for longer periods, gradually building up to more challenging distances or time frames. This sustained effort helps in burning more calories during your swim sessions."