Our Saturday morning email features the very best news and exclusive content from our team of reporters Sign me up! Thank you for subscribing See our privacy notice Invalid Email

People always wonder how much sex is enough sex and how long intercourse should last.

There are a whole host of factors which impact our sex lives, or lack thereof, including age, health, sex drive and lifestyle to name a few.

But now someone has gone and worked out how much sex we should be having, the Mirror online reports.

A recent study from the Kinsey Institute for research in Sex, Reproduction and Gender suggests that it's this variable (age) which can predict how often we have sex.

So is there such a thing as "normal"? And are we setting our sights too high (or too low)?

Some of the findings aren't that surprising.

For example, people between 18 and 29 are having the most sex, with an average of 112 sex sessions per year, or twice a week. Good for them.

30 to 39 year olds have sex 86 times per year, which averages out at 1.6 times per week.

Things go slightly downhill from here. Those in the 40 to 49 age group manage to have sex only 69 times per year.

But the declining number tells a wider story; family obligations, daily stresses and worries and an increase in health issues all play their part in impacting our libidos.

Feeling old plays its part too.

(Image: Getty)

"The basic storyline that has emerged from these studies is that, as we get older, our odds of developing chronic health conditions increases and this, in turn, negatively impacts the frequency and quality of sexual activity," wrote Dr. Justin Lehmiller.

What about duration? How long should sex last?

Well, science has weighed in (again) to tell the world exactly how much time they should be spending in the act of physical love: 5.4 minutes.

"If you're a non-scientist, you might have once asked yourself, propped against the bedhead after disappointingly quick intercourse, how long does sex 'normally' last?" Dr Brendan Zietsch from the University of Queensland wrote in The Conversation .

"A scientist, though, would phrase the same question in an almost comically obscure way: What is the mean intravaginal ejaculation latency time?

"I know there's a lot more to sex than putting the penis into the vagina and ejaculating, but the rest is not always easy to define (kissing? rubbing? grinding?).

"To keep things simple and specific, we'll just focus on the time to ejaculation."

Dr Brendan Zietsch recounted a study in which 500 couples were armed with a stopwatch and asked to press the button (of the clock) when the unspeakable act begun and then tap it again when the man experiences his magical moment.

"That is as practically awkward as it sounds: participants pressed 'start' at penile penetration and 'stop' at ejaculation," he added.

"You may note this could affect the mood somewhat, and might perhaps not exactly reflect the natural flow of things.

"But science is rarely perfect, and this is the best we've got."

Video Loading Video Unavailable Click to play Tap to play The video will start in 8 Cancel Play now

This study found that sexy time lasts anywhere between 33 seconds and 44 minutes, with the median time coming in at 5.4 minutes.

Interestingly, the research also explores "conventional wisdom regarding penile sensitivity and its relationship to staying power in the sack".

Older men weren't able to last longer than young ones, while wearing a condom or being circumcised didn't boost chaps' performance either.

"Another surprising finding was that the older the couple, the shorter the sex, contrary to the prevailing wisdom."

A study by researchers at Erciyes University in Turkey have found that overweight men last longer in bed.

Titled "Insight on pathogenesis of lifelong premature ejaculation: inverse relationship between lifelong premature ejaculation and obesity," the study's findings seem to point at a correlation between being overweight and stamina.

According to the study, the larger men with more stomach fat and a higher BMI could last for an average of 7.3 minutes in bed.New research shows regular romps are good for you - and you could actually be missing out on a whole host of positive side effects by skipping the nookie.

What happens if you don't have sex?

Some studies suggest having less sex could increase your risk of heart disease or even stop you getting aroused in the future, reports the Daily Mirror.

So here's a list of possible side effects from scrimping on the sex from website HackSpirit .

1. More stress

A landmark study in 2005 suggested intercourse is far more effective than masturbation for relieving stress.

The research, which was published in the journal Biological Psychology, showed how sex increases the levels of endorphins and the hormone oxytocin.

Oxytocin has been shown in studies to offset the effects of stress-causing hormone cortisol.

2. You get sick more often

Studies show sex makes the human body produce more Immunoglobin A, the antibody which fights off illnesses.

Wilkes University in Pennsylvania says people who have sex twice a week produce 30% more Immunoglobin A than those who abstain.

3. Higher risk of heart disease

Some scientific studies have found that having sex twice a week halves a man's chances of getting clogged arteries compared to those who indulge less than once a month.

It's believed that men getting regular sex often have better circulation and healthier blood vessels.

4. Slower brain growth

Sex could actually make you smarter in your old age.

Studies by Oxford and Coventry universities found people who had regular romps scored higher on tests for fluent speech and ability to perceive objects visually.

Another study found middle-aged rats produced new brain cells after mating.

5. It's harder to get an erection

A 2008 American study showed men who had sex less than once a week were actually twice as likely to develop erectile dysfunction in later life as those who performed more regularly.

6. Higher risk of developing prostate cancer

Research published in the US shows men who ejaculate 21 or more times a year had a 33 per cent lower risk of developing prostate cancer .

It has been speculated that orgasms lessen the risk by lowering stress and regulating the metabolism of cells.

But if you've lost your libido, regular exercise, quitting smoking and eating will help with this.

7. You'll be less stimulated

Women's bodies can react adversely to a lack of action.

No sex for a long time can lead to problems getting aroused or reaching an orgasm.

8. Less lubrication

After a break from sexual activity, the vagina can fail to lubricate properly.

The cause is said to be a lack of the hormone oestrogen, which makes older women particularly susceptible.

Younger women in their 20s and 30s are far less at risk from the side effect because they already produce plenty of the hormones.

9. Porn might not help

Experts say frequent watching of pornography can de-sensitise men and make them less likely to get aroused in the bedroom.

Males in their late teens and early 20s who watch explicit material could suffer the kind of problems middle-aged men suffer.