Lee Suckling: Why people have more sex in summer

Not only are people less tired during the summertime, they also generally eat healthier, do more exercise, and are more sociable. Photo / Getty Images

Summer is the time for lovin', or so the cliché goes. According to researchers, your sex drive does actually increase during the summer months. Is this simply because you have more time on your hands, or something more?

Harvard Medical School psychiatrists believe it's the sun that makes you randier. Exposure to sunlight makes you feel happier by increasing serotonin levels. These are some of the main neurotransmitters that allow you to experience pleasure. When they are high, your brain continues to fuel its high by seeking out other pleasures – one being that of the flesh. Sunlight's Vitamin D (excuse the pun) can also help with testosterone levels which can improve sex drive.

This is helped even more by the fact that flesh is on display. When you are wearing less clothing, and the skin of others is also on display, you may make subconscious connections to sex. Just think about the reverse: in winter, when you're bundled up in jackets and scarves and never see others' bodies, let alone your own, sex just mightn't factor into your thoughts so much.

During summer you have less melatonin in your body because of reduced exposure to darkness, which helps to increase your libido because melatonin – the natural chemical that makes you sleepy – blocks sex hormones.

Not only are people less tired during the summertime, they also generally eat healthier, do more exercise, and are more sociable. All four of these things contribute to feeling more confident about yourself and your body, which inevitably can lead to increased desire for sexual activity.

As noted last week in the Sex Files about the benefits of hotel sex, there's also a direct correlation between being on vacation and wanting more sex. Most of us have taken time off work in the last month and this freedom of time, location, and choice makes us feel more free with our bodies as well.

Interestingly, Google searches for dating apps and website, pornography, and even sex workers also go up during the warm season. This moves on from this notion that people have more sex in summer, and shows us that people are just generally hornier with all of this external stimulation.

The bad news

The result in all of these summertime sexual vibes is – you guessed it – greater STI transmission between December and February. An eight-year Australian study by the Melbourne Sexual Health Centre reported that patients' sexual partners rose during this three month period compared to the other nine months of the year, as did end-of-summer diagnoses for chlamydia and gonorrhea for both sexes.

Yet it's not all sex and sunlight at this time of year. Being too hot and sweaty to have sex is a reality too – the US's National Bureau of Economic Research has studied the birth of babies and probable conception dates, and found that baby-making is actually unlikely to occur on the hottest days of the year. Anyone caught up in a humid January evening in New Zealand might find this relevant: you're more interested in the breeze from your fan than having another hot body on top of you.

According to condom manufacturer Trojan, 35 per cent of people have actually turned down sex

because of the heat. So, if your sex life hasn't ramped up much this summer, rest easy. It might simply be because you've been more interested in a literal cold shower than a figurative hot and steamy one.