If you're trying to burn calories you might want to swap the dumbbells for a pair of boxing gloves.

fighters can burn up to 800 calories an hour in the ring, making it the best sport for weight loss. Squash came in second at 748 calories followed by rowing and then running.

Sex burns just 200 calories an hour for men and only 138 for women.

Down at the bottom of the scale was housework, shopping and having a bath - all coming in under 100 calories

With watching telly on the sofa bottom of the list at zero calories an hour.