People should jump in the sack before hitting the hay if they want a good night's sleep, according to a top researcher.

Researcher Dr Michele Lastella said having sex before going to bed could be the key to getting the perfect night's sleep.

But Dr Lastella revealed the quality of sleep relied on the mutual satisfaction of both parties.

'What we found was 64 percent of our respondents indicated they slept better when sex was with a partner and it involves an orgasm,' he told Adelaide Now.

From a survey of 460 adults aged between 18 and 70, Dr Lastella found people found it increasingly difficult to 'switch off' before going to sleep.

'There's strong evidence to suggest substituting screen time for play time,' he said.

'When you're engaging in sex, you're not thinking about what to do the next day, you're not going through your phones. It distracts you.'

A similar study, conducted by Oxford Economics and the National Centre for Social Research, found a good night's sleep and having good sex far outweighed the impact on well-being, than money.

'Better sleep is the biggest single contributor to living better,' the researchers said.

Those who described themselves as most happy, also reported being more satisfied with their sex life.

Adelaide couple Frank Marafioti, 28, and Dani Caceres, 22, said they were not surprised by the poll results.

'I think you would be feeling relaxed and a sense of relief (after sex),' Mr Marafioti told Adelaide Now.

DailyMail.