Ditch the diet and expensive gym membership, anyone who wants to lose weight this year needn't leave the bedroom, according to new research.

Scientists have found that a night of passion can match a workout class, as sex counts as
"significant exercise".

Researchers found that men burn 120 calories from half an hour between the sheets, while women can lose 90 calories.

It means people can burn as many calories from just over an hour of love-making than they can from a 30-minute jog.


Researchers argue that this sex-ercise breakthrough could shape weight loss regimes of the future.

The study, Energy Expenditure During Sexual Activity In Young Healthy Couples, has been published by the Public Library of Science.

Scientists from the University of Quebec in Canada recruited 20 heterosexual couples, aged 18 to 35, to have sex once a week for a month.

The subjects, who were also asked to jog on a treadmill for 30 minutes, were fitted with armbands to measure how much energy they were expending and fill in questionnaires to record their enjoyment.

"These results suggest that sexual activity may potentially be considered, at times, as a significant exercise," the paper concluded.

"Moreover, both men and women reported that sexual activity was a highly enjoyable and more appreciated than the 30 min exercise session on the treadmill.

"Therefore, this study could have implications for the planning of intervention programs as part of a healthy lifestyle by health care professionals."

The researchers recorded the number of calories each person burned and their metabolic equivalent of task (MET), which compares an activity to sitting still, measured at 1-MET.

The results showed that men burned on average 4.2 calories a minute, compared to 9.2 on the treadmill, while women burned 3.1 calories a minute during sex and 7.1 jogging.

The study also recorded an average 6-MET for men during sex and 5.6-MET for women, roughly the same as playing doubles tennis or walking uphill.

When on the treadmill, men recorded an 8.5-MET, while women registered an average 8.4-MET.

But for brief periods during sex, some of the men actually used more energy than they did while on the treadmill.

"Sexual activity is an important and relevant activity to human life and appears to impact on the mental, physical and social health as well as the quality of life of the individual," the study said.

"Considering that sexual activity may be one of the most regularly practiced activities throughout an individual's life time, it seems important to conduct research on this topic."