The media might be obsessed with women’s egg counts, but male fertility shouldn’t be left out of the conversation.

Researchers are warning men’s sperm counts are falling at such rates that humans could fall under threat of extinction in the future. After assessing 185 sperm studies, they found sperm counts among men from North America, Europe, Australia and New Zealand, seemingly halved between 1973 and 2011 (lead researcher Dr Hagai Levine is “very worried” about the implications).

[Read more: What is an ectopic pregnancy and can it affect your fertility?]

So, should we be concerned? A little perspective is probably wise – other experts have noted that the Human Reproduction Update findings don’t necessarily give the full picture because, for instance, some of the older studies may have been flawed, plus sperm count studies that don’t find any significant drops may not always be published, therefore getting left out of the equation.

However, male fertility shouldn’t be taken for granted. And while, like all aspects of health, sometimes things are out of your control (and there are often things that can be done to help, if you do experience fertility difficulties), lifestyle factors can play a part. Here are 9 key things to keep in mind…

1. Smoking

“Smoking can affect your general health and fitness and so have a detrimental effect on the quality of sperm produced,” says Mr Dev Sarmah, consultant urologist at Spire Parkway Hospital in Solihull. “There’s also the problem that [smoking] can lower levels of the antioxidants in the body that protect the sperm from attack from ‘free radicals’. Certain tests have also shown that couples undergoing fertility treatment get poorer results if the male partner smokes.”

Quitting smoking isn’t easy – but there’s tons of support out there to help, including NHS Smokefree services. Ask your GP about services in your area.

2. Stress

“Stress hormones can interfere with the hormones controlling sperm production. Research has shown that men under stress at work or home are more likely to have poor sperm quality,” says nutritionist Dr Marilyn Glenville PHD, author of Getting Pregnant Faster.

A balanced diet, getting enough sleep and regular exercise are all important for helping manage stress, as well as taking steps to address any particular triggers – such as issues at work, and saying ‘yes’ to everything and not leaving time to recharge. “Yoga or meditation can also be helpful, as well as seeing a counsellor, as infertility in itself can be stressful,” adds Dr Glenville.

3. An unhealthy diet

Generic photo of two plates of food (ThinkStock/PA)
Everything in balance (Thinkstock/PA)

A poor diet can impact our health in general, which may contribute to reduced fertility. A balanced diet, with plenty of anti-oxidant-filled fruit and veg, is usually the best approach.

Plus, Dr Glenville notes: “One of the most important nutrients for male fertility is zinc, needed for the production of sperm and male hormones. Several studies have found the male sex glands and sperm contain high concentrations of zinc. Modern diets tend to be low in zinc, so make sure not to deprive yourself and opt for foods such as fish, sardines, eggs, whole grains, brown rice and nuts.”

4. Over-exercising

Generic photo of road cyclists (ThinkStock/PA)
Does cycling really affect sperm? (Thinkstock/PA)

“In a world where everyone is encouraged to keep fit, it may seem strange to include ‘over-exercising’ as a reason why sperm quality may be poor,” says Mr Sarmah. “However, as with everything, things work best in moderation.

“It is possible excessive exercise could lower the amount of testosterone in your body – but I would not want to discourage anyone from taking regular exercise and plenty of it.”

In the past, cycling has also been associated with reduced fertility in men – but there’s no clear evidence to suggest this applies to most people, and remember, it’s far better overall to be fit and healthy than avoid exercise.

5. Too much caffeine

Sure, the health benefits of coffee regularly feature in headlines these days, but too much caffeine could still have detrimental effects in other ways. “Studies indicate that problems with sperm health seem to increase the more cups of coffee men drink a day,” notes Dr Glenville. “This may be because caffeine has a diuretic effect and this can deplete the body of vital fertility boosting nutrients, such as zinc and calcium.”

6. Too much alcohol

Generic photo of a row of pints of beer (ThinkStock/PA)
Too much booze can impact health in lots of ways (Thinkstock/PA)

“Excessive alcohol lowers testosterone levels, and so affects both the quality and quantity of sperm. There’s also the problem that drinking too much can reduce male libido as well as causing impotences,” says Mr Sarmah.

Excessive drinking can sometimes be associated with mental health problems in men too. It’s a good idea to talk to your GP, or call a mental health charity helpline, such as the Mind infoline, if you’re struggling to cope or simply want some advice about finding healthier ways to tackle life’s ups and downs.

7. Being overweight

“Being overweight or obese can cause hormonal changes that lower the quality of sperm, and make men less interested in sex,” says Mr Sarmah. “Very overweight men are also more likely to have problems getting an erection. It’s also true that excessive fat increases body temperature around the testes, which can also affect sperm quality.”

8. Poor sleep

Generic photo of a stressed man at his desk (ThinkStock/PA)
Stress + tiredness = time for a recharge (Thinkstock/PA)

A lack of sleep can impact health in many ways, and this might include fertility. “If you are constantly tired, then your sperm count will go down,” says Mr Sarmah. “You also need to look at the reasons why you aren’t sleeping well – could it be stress or an unhealthy lifestyle? Both factors that can affect sperm quality.”

9. Over-heating

Some studies have suggested prolonged exposure to high temperatures can have a negative impact on sperm production, leading to occasional headlines warning of the dangers of working in hot environments, using your laptop on your lap, etc. While this might be a grey area in reality, ‘prolonged exposure’ are probably key things to remember here, and if you’re concerned, have a chat with your GP.