The best time of day for having sex with your partner depends on how old you are, according to a sleep and body expert.
Rather than sex being a spontaneous act, there are in fact times of the day when libido is higher depending on whether someone is in their twenties, fifties or seventies according to Dr Paul Kelley.
Dr Kelley, a clinical research associate at Oxford University's Sleep and Circadian Neuroscience Institute, said body clocks change over each decade, according to some research he originally carried out for the Daily Mail.
"Your body clock changes with age, when you feel like waking up. It actually controls every body system and controls every one of the trillion cells in your body," Dr Kelley told the Telegraph. "In most things we've got the timings right, but we haven't accounted for these changes".
So when is the optimal time for each age group to have sex?
* Twenties - 15:00. Dr Kelley has narrowed down the peak of libido for this age bracket to three o'clock in the afternoon. While they can want sex at any time of the day, there is a peak of sexual energy at this point for the twenty-somethings.
* Thirties - 8:20. A shift in body clock at this age means you wake up earlier - so having sex earlier is a good idea. Dr Kelley pinpoints the magic minutes around 8:20 am, when sunlight boosts testosterone in both men and women.
* Forties - 22:20. Again, you will feel more alert earlier the older you get, so you need to go to bed earlier. Dr Kelley recommends sex some time after 10pm before you go to sleep.
* Fifties - 22:00. As bedtime gets earlier, time for sex does too. The mornings tend to be busier for 50-something-year-olds, Dr Kelley told the Telegraph, so is not an ideal time for intimacy.
* Sixties - 20:00. After an orgasm you release oxytocin, which is a wakefulness hormone - and as you go to bed earlier in your late age, you may want to have sex sometime before trying to sleep.
* Seventies - 20:00. The same as above is true of 70-year-olds, who should rise earlier around 6:30am and will need to hop into bed earlier too.
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