The top five calorie-killers include cross-country skiing, step, skipping, running and boxing. Personal trainers recommend two to three 45-minute sessions a week in order to see results.

Cross-country skiing, 974 calories per hour, uphill 
Skiing works muscles in the lower body hard (quads, calves, glutes). Muscular activity increases with speed, which can explain that burning thigh feeling often associated with the sport. Skiing also strengthens abdominal muscles, as well as the back, shoulders and arms.

Garmin Vivofit

Step, 876 calories per hour 
A step aerobics class is a full-body workout, since arms are also included in the dance-style moves. During longer sessions (between 30 and 45 minutes), the body burns sugars then dips into fat reserves as a source of fuel. Step is great for slimming down waistlines and strengthening muscles.

Skipping, 800 to 850 calories per hour
Jumping rope is an excellent cardio exercise for improving physical fitness, bringing benefits to the whole cardiovascular system. Skipping can aid weight loss, and it's a great way to tone up arms and calves quickly.

Running, 600 to 800 calories per hour 
Running is one of the best sports out there for burning calories and losing weight. An all-round workout, running boosts cardiovascular fitness and strengthens back and abdominal muscles, as well as the lower limbs, working both the legs and the buttocks.

The Garmin Forerunner 630

Boxing, 600 to 800 calories per hour
Boxing is a punch-packed sport that hits hard in the body's energy reserves! This activity is available in some form or another at loads of gyms and sports clubs (traditional boxing, Body Combat, BoxFit, etc.) for a workout combining speed and technique. Boxing works the arms, abdominal muscles and legs.

Swimming, 600 calories per hour 
This no-impact sport minimises damage to joints while effectively working all the muscles in the body (shoulders, arms, back, abdominals, buttocks, legs) for a workout that's much more intense than it might feel.

Cycling, 400 calories per hour
Cycling is a great way to ease back into exercise, working the heart, abdominals, legs and buttocks with a low level of impact on joints. Indoor cycling classes burn 675 calories in 30 minutes. The sprint cycling techniques used in these so-called "spinning" classes boost cardiovascular activity for rapid results. [AFP Relaxnews]