64% of our respondents indicated they slept better when sex was with a partner and it involves an orgasm, reports The Advertiser.

Dr Lastella, based at CQUniversity’s Appleton Institute for Behavioural Science in Adelaide, said sex may also produce “a biochemical cocktail” — an increase in oxytocin and prolactin and a decrease in the production of stress hormone cortisol, which “can leave us feeling quite relaxed.”