The lips are packed with nerve endings — 100 times more than the fingertips

The act of sex sets off a cascade of hormones, which trigger pleasure, happiness, and bonding, scientists reveal. Studies now show that intercourse is good for our health, from protecting against heart disease and osteoporosis, to staving off dementia and improving mood.

Why love hurts
A key hormone released during sex is oxytocin, also known as the ‘cuddle hormone.’ This lowers our defences and makes us trust people more, says Dr Arun Ghosh, a GP specialising in sexual health at the Spire Liverpool Hospital. It’s also the key to bonding, as it increases levels of empathy.

Women produce more of this hormone, although it’s not clear why, and this means they are more likely to let their guard down and fall in love with a man after sex. However, the problem is that the body can’t distinguish whether the person we’re with is a casual fling or marriage material — oxytocin is released either way. So while it might help you bond with the love of your life, it’s also the reason you may feel so miserable when a short-term relationship ends.

Men, on the other hand, instead of getting a surge of bonding hormone, receive a surge of simple pleasure. “The problem is that when a man has an orgasm, the main hormone released is dopamine — the pleasure hormone. And this surge can be addictive,” says Dr Ghosh. That’s why so many more men tend to suffer from sex addiction.

Staving off dementia
Many of us are all too aware that our brain cells decline with age. In fact, it’s said we lose 7,000 brain cells a day by the time we’re 35, which makes rather depressing reading. The good news, however, is that having regular sex may help us grow new brain cells, according to scientists from Princeton University in the United States. 

And the more sex you have, the more cells you can grow, it seems. Animal studies, published in the journal PLoS ONE, suggest that sex stimulates the growth of brain cells in the hippocampus, the part of the brain responsible for memory and learning. Factors such as stress and depression have been shown to shrink the hippocampus, yet exercise and sex counteract this effect.

 Furthermore, sex could actually be protecting our brain cells against decline. “There is some evidence that older people who are sexually active are less likely to have dementia and this could be for a variety of complex reasons,” says Dr Ghosh. Sex causes increased blood flow to the brain, which improves oxygen levels. “MRI scans have shown that during orgasm, the neurons in the brain are more active and use more oxygen,” explains Barry Komisaruk, professor of psychology at Rutgers University and a leading authority on sex and neuroscience.

“It appears that the more active the neurons, the more oxygen they withdraw from the blood — so more oxygenated blood is supplied to the region, delivering a fresh supply of nutrients.” But as well as boosting brain cells, sex could also sharpen a woman’s mind, says Dr Ghosh. That’s due to a surge in sex hormones, particularly testosterone, which can help improve concentration and reaction times.

Smooching means better sex
The lips are packed with nerve endings — 100 times more than the fingertips. As a result, kissing kick-starts multiple mechanisms in the brain, releasing chemicals that lower stress and boost mood, says Dr Ghosh. “You’ll have much better sex if you kiss before intercourse,” says Dr Ghosh.

It increases levels of the pleasure hormones and will make you a lot more receptive to what happens later. “That’s why loving sex can be more satisfying than a quickie — and that endorphin hit from dopamine is especially important for women.”

A natural painkiller

Orgasm (rather than sex) can block pain signals, says Professor Komisaruk. Research using laboratory animals and humans has found that orgasm can inhibit the release of pain transmitters from the spinal cord so they can’t reach the neurons in the brain that respond to pain. In fact, he says, it can raise the pain threshold so much that the equivalent effect in morphine is three times the usual pain-relieving dose.

Its's a good way to test our eyes

Sex relaxes the muscles and alleviates neck and shoulder tension, says Dr Arun Ghosh. And surprisingly, it might also tell you whether you need glasses.

“I’ve had patients complain of poor vision after sex. What’s happened is that, like all the other muscles in the body, their eye muscles have relaxed and are performing at their true ability, rather than straining and squinting as they would normally,” Dr Gosh reveals. So if your sight goes blurry after sex, it’s worth going for an eye test.

It protects against heart disease
Sex can have a protective effect on the heart. A study at Queen’s University in Belfast found that having sex three times a week could halve the risk of heart attack or stroke. Another study in Israel found that women who had two orgasms a week were up to 30 per cent less likely to have heart disease than those who didn’t enjoy sex or didn’t orgasm. 

Dr Lisa Turner, a sex and relationship therapist, says: “One theory is that these women may have felt depressed, which has been linked with an increased risk of a heart attack.The endorphins released during sex also neutralise the stress hormones in the body, which are linked to heart disease.”

And the old cliche of sex causing heart attacks?
“It’s a very low risk — it accounts for less than 1 per cent of all deaths,” says Dr Graham Jackson, consultant cardiologist at the London Bridge Hospital and chairman of the Sexual Advice Association. However, if you’re over 50, overweight and unfit, there is a risk to your heart — just as there would be if you suddenly and vigorously took up any form of exercise.

“What also increases the risk is extra-marital affairs, and this has been proven by three large studies,” says Dr Jackson. “In fact, this accounts for 75 per cent of heart-related deaths from sex, 90 per cent of which are older men. It’s thought the combination of high-fat foods and alcohol — wining and dining — combined with vigorous exercise, often with a younger partner, is what tends to trigger the heart event.”

It makes you more fertile
“I’m often asked whether penis length affects fertility and the good news is no,” says Dr Ghosh. But the amount of sex you have is important. The more often you make love, the better quality your sperm will be. “If you’re trying to conceive, you need the sperm to be as fresh as possible — not stuff that’s been sitting in the prostate for three or four days,” he adds.

It staves off prostate cancer
Researchers at Nottingham University have found that men who enjoy a regular sex life in their 50s are at lower risk of developing prostate cancer. “Clearing the prostate out regularly is the reason behind this,” says Dr Ghosh. “The link was suggested after research showed that monks appear to have a higher chance of developing prostate cancer.”

It'll help you quit smoking
Here’s a simple way to get your man to kick his smoking habit — remind him that it causes the penis to shrink and can cause impotence. Erections are all about good blood flow, and lighting up worsens blood flow to the spongy tissues in the penis, says Raj Persad, consultant urological surgeon at Bristol Royal Infirmary. “As a result, they become starved of oxygen and the delicate cells die away.

They then become fibrotic — forming scar tissue — which is less elastic and less able to expand during an erection than regular healthy tissue.” Smoking is also a known cause of erectile dysfunction as it causes hardening of the arteries and hampers good blood flow. A study of more 7,000 Chinese men, published in the American Journal of Epidemiology, found that the more cigarettes smoked a day, the higher the risk of impotence.

 - Courtesy of DailyMail/Anna Hodgekiss