You've probably known for a while now that you quite like having sex – but what you may not have realised is just how good it is for you.

Yes, that's right: sex helps to keep you healthy. And we're not referring to that hoary old playground myth that a tumble in the hay three times a week is the same as running a marathon every year (it's much more). No, sex is beneficial for an array of scientifically proven reasons – and since today is World Sexual Health Day, now is a good time to learn them.

So, dim the lights, put some Barry White on, and snuggle up with our low-down on how more sex can improve your life ...

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Sex is a natural painkiller

According to research in the Bulletin of Experimental Biology and Medicine, orgasms half the body's sensitivity to pain, due to the flow of endorphins (read: natural painkillers) they create. What's more, those endorphins take effect in a matter of minutes – which is far quicker than most over-the-counter drugs available on the high street.

So, the next time your partner claims that he or she "has a headache," politely inform them that the best remedy is a spot of sexual healing. All together now ...

Sex combats illness

You know those people who say "I never get ill"? Well, it's possible that they're revealing more about themselves than they realise.

According to a study carried out in Pennsylvania and published in Psychology Report, people who have sex once or twice a week have, on average, 30pc more Immunoglobulin A (IgA), which is used to fight illness, than those who are not sexually active.

However, it's worth pointing out that this link between intercourse and immunity is not always positive. The same study found that the people with the lowest level of Immunoglobulin A were those who had sex more than twice a week.

Sex beats stress

Do you lie in bed awake at night worrying about tomorrow's meeting or that big DIY project on the horizon? Well, rather than turning the problems over in your head, the best course of action might be turning your partner over and making a play for a spell of stress-easing sex.

According to a study that was published in Biological Psychology, men who have recently had sex respond better to stressful situations.

To an extent, this should come as no shock: sex is largely considered to be an enjoyable pastime, so it's natural that it lowers your stress level. However, what is more surprising is the de-stressing affect that mere touch has. Another experiment, published in Behavioural Medicine, looked at couples who held each other's hands for 10 minutes, followed by a 20-second hug. They were shown to have healthier reactions to subsequent stress, such as public speaking, than couples who rested quietly without touching.

The huggers also had: lower heart rates, lower blood pressure, and smaller heart rate increases.

What he needs is a good ... Credit: Alamy

So, if your partner isn't interested when you turn him or her over, settle for a nice snuggle instead.

Sex helps the heart

Men who have sex at least twice a week can almost halve their risk of heart disease, according to research published in 2010 by scientists at the New England Research Institute in Massachusetts.

The study, of over 1,000 men, showed that sex has such a protective effect on the male that its authors went as far as calling for doctors to screen men for sexual activity when assessing their risk of heart disease.

They suggested that the benefits of sex could be due to both the physical and emotional effects on the body.

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Sex powers up the brain

Ok, so it's only been proven in rats to date – but one scientific study suggests that a rumble in the (pubic) jungle can boost brain power.

In 2010, research published in the journal PLoS ONE suggested that rats who mate regularly had a higher rate of cell proliferation in the hippocampus, which is the part of the brain linked to memory. The rats also experienced more brain cell growth and a rise in the number of connections between brain cells than those who did not.

So, forget about sudoku and instead consider more virile endeavours as your brain exercise.

Who said sex isn't a thinking man's game?

Sex makes you look younger

Regular sex could now be the key to looking up to seven years younger, according to Dr David Weeks, who is the former head of old age psychology at the Royal Edinburgh Hospital.

In 2013, Dr Weeks told the British Psychological Society that sex has a number of health benefits which can make men and women look between five and seven years younger. Partly, this is due to the health benefits summarised above (a healthy person tends to look younger than an unhealthy person), but he also pointed to the release of human growth hormone in the act of love making, which makes skin look more elastic.

Another piece of research, conducted by scientists at the Royal Edinburgh University, found that couples who merrily romp at least four times a week look a whole decade younger than less libidinous twosomes. The pleasure of penetration releases positive hormones such as adrenalin, dopamine and norepinephrine, which help preserve skin cells and relax muscles, therefore preventing wrinkles.

Which all suggests that the elixir of youth might spout from a very unexpected fountain ...

Good sex helps you last longer

Not only are men who have frequent sex more likely to last longer in the sack than those who don't; they're also more likely to last longer in the world.

As you've probably figured by now, sex is good for you – which is why a study conducted in a Welsh village in 1997 found that men who have two or more orgasms a week add up to eight years onto their lives than their less passionate brethren.

''Sexual activity seems to have a protective effect on men's health,'' wrote Dr. George Davey-Smith and his team of researchers from the University of Bristol and Queen's University of Belfast, pointing to the positive effects on the immune system, heart, and brain.

'My knight takes your castle': Kim Kardashian playing chess Credit: Melissa Whitworth

Indiana Jones wonders whether he really wants to try the elixir of youth Credit: Indiana Jones and the Last Crusade