London - Put away the Sudoku… there could be a better way to improve your memory.
Academics claim that having a healthy sex life past 50 may help you to remember things.
Their findings - from a study of more than 6 000 English respondents - are believed to be connected to the "pleasure hormone" oxytocin.
It is released during lovemaking and kissing and is important for activating brain cells in the hippocampus – the memory centre of the brain.
Sleeping with or cuddling someone you are close to can also reduce stress hormones, which prevent the creation of brain cells important to the retention of memory.
Dr Mark Allen, who carried out the research at the University of Wollongong in New South Wales, Australia, said: "The finding that more frequent sexual activity was associated with better memory performance complements previous research that found sexually active older adults perform better on cognitive tasks."
The study, reported in the journal Archives of Sexual Behaviour, uses data from the Health Survey for England in 2012 and 2014. It did not find that sex prevented the decline of memory over those two years, but this could be due to the short time period concerned.
However the results did show that the middle-aged who have regular sex did better in a snapshot memory test, in which they were told ten words to remember.
The 6 016 adults were given a recording of the words, asked to recall them once, and then again after an unrelated set of tests.
Those who did better also scored more highly in a questionnaire about their sex lives.
This asked if they had experienced any sexual activity in the past year, how many times they had had sex in the past month and how frequently they engaged in kissing, petting and fondling.
Those who said they felt emotionally close to their partner during sexual activity were also more likely to do well in the memory test. While remembering ten common words like "paper", "child" and "flag" may seem basic, previous research has found the test relates to how well our memories work in everyday tasks.
A better score could even mean better performance in things such as remembering a shopping list or making important financial decisions.
The study found sex appeared most important for memory in adults over 60.4 years old, which backs up the theory that the deterioration of brains begins at 60.
It also supported experimental research that found sexual activity in male rats improves their ability to recognise things.
Dr Allen wrote that finding sex did not fully slow down memory loss was a "little surprising", but he added this was probably due to the two-year timeframe concerned in the study, and that more research is needed.