Some Olympic sports burn more calories than others. Here are the calorie-burning equivalents you can do at the gym to match Olympic workouts. Triathlons burn 2,500 – 3,000 calories, equivalent to high-intensity cardio for 3.5-5 hours. Olympic boxing burns 600-800 calories, similar to high-intensity interval training or cycling for an hour. Freestyle 1500m swim burns 150-350 calories in 15 mins, like intense weightlifting or high-intensity cardio for 30 mins. A 10,000m race burns 400-600 calories, similar to an hour of swimming or 45-60 mins of high-intensity cardio. Breakdancing and skateboarding both burn around 500-600 calories per hour, equivalent to rigorous cardio or intense weightlifting in the gym. Surfing burns around 600 calories per hour, similar to high-intensity cardio.