Sex is arguably the oldest - and most enjoyable - form of exercise.
However you do it, it burns calories. But, if you really want to kill two birds and get a workout in while spending some 1:1 time with your other half, it's worth knowing which sex positions bring a sweat on.
The top calorie burner? The so-called 'butter churner'.
Not for the inflexible, this involves a woman lying on her back with her legs up and behind her head with a man penetrating from behind.
This positions's estimated to burn up to 211 calories per half hour, reveals healthcare website From Mars who shared their findings from their custom-made sexercise calculator.
Second is the standing position which can burn up to 198 calories in 30 minutes. However, according to previous research, this position results in one of the lowest rates (17%) of orgasm for women.
Watch now: How to get more pleasure out of common sex positions
Doggy style is the position that ranks in third place, with up to 182 calories burned in half an hour. Happily for ladies, it's the position that research has shown makes most women orgasm (79%).
Spooning may not seem the most energetic of positions, but even this position is estimated to burn up to 100 calories per 30 minutes.
And even oral sex can be a calorie burner with the '69' position burning up to 78 calories.
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Burning calories and keeping fit aren't the only health benefits of sex. Research has shown that engaging in intercourse can help lower your blood pressure, promote better sleep quality, reduce physical and mental stress, as well as improving self-esteem.
Sex is also a great workout for a woman’s pelvic floor muscles – the muscles that control orgasms and also stem the flow of urine, reducing leakage and incontinence.
Pregnancy and the menopause can weaken these muscles significantly, but the stronger they are, the lower your risk of developing stress incontinence and prolapse later.
Several studies have found that regular sex can ward off heart attacks, not bring them on as it was once feared.
And sex can actually help keep you looking younger as the hormone oestrogen is pumped out during sex, which can in turn have a plumping effect on the skin, helping to smooth out those fine lines.
As if we needed an excuse to swap the gym for our beds...