In the last half a century, fertility issues have gone from being almost unheard of, to swiftly becoming a fairly common phenomenon – affecting up to 1 in 6 couples.

It’s difficult to pinpoint exactly what the cause is behind this worrying trend, but some aspects of our modern lifestyles are likely to be a big part of the problem.

Our diets have completely changed in recent years, every day we are exposed to an abundance of toxic chemicals and people of reproductive age are increasingly putting themselves under incredible stress in fast-paced and exhausting rat-race type careers. And these are just a handful of our problems.

All these lifestyle factors bring with them a range of health problems, some of which will influence a person’s fertility and some of which we probably don’t even know about yet.


The main indicator that’s used to determine if a man has any fertility issues is the quality of his sperm. Sperm quality is made up of four different aspects. The number of sperm produced, how well they can move, their physical characteristics, and the quality of their DNA.

Currently, only one in four men has sperm that is considered to be of ‘optimal quality’. One research study even found that the sperm count of French men has decreased by 32.2% between 1989 and 2005.

So despite the fact that the blame is often placed on women – it has been estimated that up to half of all cases of infertility can be linked back to malefactors.


A new study, published in May in the Fertility and Sterility Journal, has helped to unravel some of the reasons behind the declining quality of sperm.

Researchers at Stanford University, California, looked at the quality of sperm in men trying to conceive in relation to their occupations and general health.

The study, which is one of the first of its kind, found that working in a physically challenging job, taking multiple medications, and having high blood pressure are all associated with having a lower sperm quality.

In total, 456 men trying to conceive were examined for about a year. The average age of these men was 31.8 years. They provided sperm samples and were each asked questions about their lifestyles, reproductive history, general health, and occupations.

The researchers discovered that 13% of men who reported working in a job that involved ‘heavy exertion or lifting’ had a lower sperm count than normal, compared with only 6% who didn’t. But – perhaps surprisingly – shift work, night work, vibration, heat, noise, and prolonged sitting at work were not linked to sperm quality.

Men who had been medically diagnosed with high blood pressure had a lower percentage of sperm with normal characteristics and shape (17%) compared with men who reported having a normal blood pressure (21%). However, the researchers stress that it’s important to further investigate whether it really is high blood pressure causing this effect and not the treatment that men are receiving to treat their blood pressure.

On the other hand, high cholesterol and diabetes did not seem to affect sperm quality in the men studied.

It also seemed that the more medications a man was taking, the more likely he was to have a lower than normal sperm count. A man’s sperm count is considered normal if he produces between 40 and 300 million sperm per milliliter. In the study, only 7% of men who did not take any medications had sperm counts below 39 million, whereas 15% of men who took two or more medications had a sperm count below this normal threshold.

Professor Allan Pacey, fertility and sperm specialist at the University of Sheffield said:

The study suggests that several medical conditions as well as the number of medications a man takes might have a negative influence on semen quality. Often we don’t really understand the effects that medications have on male fertility, so this is useful information to know.

Although if men do need to take medicines prescribed by a doctor, then they should continue to do so. If men have concerns about their fertility they should discuss them with the doctor who is in charge of their medical care.


A further study brought to light another lifestyle factor that may influence a man’s sperm quality. The amount of sleep he gets.

The research was focussed on 953 young Danish men who provided sperm samples and were questioned about their sleeping patterns using a regimented scale to determine their level of sleep disturbance.

Men who reported having a high level of sleep disturbance had a 25% lower sperm count and 1.6% fewer sperm with normal physical characteristics than men with less disturbed sleep.
This is especially important when it comes to couples who are trying to conceive, as men of reproductive age are finding themselves getting less and less sleep because of the hectic lives they lead.

The researchers were unable to say exactly what mechanism was behind this link between sleep disturbance and lower quality sperm.

Although Professor Pacey believes this is a problem with studies of this kind, he said:

I don’t doubt that sleep deprivation has some effect on semen quality because it can disrupt all aspects of physiology. I think it’s just important to get good quality sleep and try and remain healthy when talking about the best way to boost your chances of conceiving.


Many men are leaving it later in life to have children. Unfortunately, some of the issues studied (such as high blood pressure and the prescription of multiple medications) are more prominent in older men.

As the lifestyle choices and health issues that are associated with older men are often different to those associated with younger men, the shift in the average age of fathers has made it important to re-examine factors that we never thought would be important in relation to fertility.

What’s more, the DNA in sperm and sperm-producing cells of older males is more prone to accumulating errors – known as mutations – which can be passed onto children.

So – when it comes to trying to conceive – the odds can be stacked against older men (to an extent).

It’s therefore crucial that these men do all they can to lead a healthy lifestyle in order to ensure their sperm is as healthy as possible.


It’s important that more research is carried out to confirm the exact mechanisms behind how lifestyle and health factors can influence sperm quality.

But, the good news is that many of the everyday threats that pose a danger to a man’s sperm quality can be avoided.

Threats associated with medications, medical issues, and occupations can all be controlled through careful medical management and work-place regulations.

As scientists find out more about the everyday threats undermining sperm quality, we will be able to put in place more protective and preventative measures to keep sperm in top form!
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