If you’re not giving it to your lady the way she wants, or if you’re giving it to her faster than she wants, you can usually take some comfort in the fact that at least there’s nothing wrong with the quality of your semen.

(Related: Is tight underwear damaging your sperm)

But new research has suggested that some men aren’t even getting that right, with a lack of exercise and junk food contributing to men having fewer and fewer working swimmers.

(Related: Study confirms women prefer younger looking men)

Researchers at the Sidney Kimmel Medical College and fertility clinic IVIRMA monitored almost 120,000 men worried about the state of their sperm in Spain and the US from 2002 to 2017.

The men were put into three distinct groups based on the number of swimming sperm in their semen samples, ranging from the most fertile group, who had more than 15 million moving sperm, to men with five million swimming sperm or less.

They found that in the most fertile group the men’s sperm count went down by 1.8 per cent each year, while the proportion of men in the least fertile group increased from less than 9 per cent of the total to 11.6 per cent.

“We did not expect to see the same fall in sperm quality in Spain and the US. If this trend continues, there is potential for more men to become infertile,” said Dr James Hotaling, a co-author of the study.

(Related: Are your gym gains killing your sperm count)

A second study, led by Icahn School of Medicine at Mount Sinai, New York, also found that fertility declined over 11 years in the US cities of Los Angeles, Palo Alto, Boston, Houston and Indianapolis.

(Related: A man's sperm is stronger the second time he ejaculates)

If you’re worried about your fire power then the NHS advises that staying in good shape, exercising regularly and having a healthy, balanced diet are all important ways to boost your sperm count. You could also try eating more oily fish. A recent study in the Journal of Nutrition found that fish could boost men’s sperm count by a massive 65 per cent.

If you want to increase your potency, junk food and a sedentary lifestyle are never going to be the way to do it.

Daniel Davies Daniel Davies is a staff writer at Men’s Health UK who has been reporting on sports science, fitness and culture for various publications for the past five years.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io