Drawn from our Men's Health Week conversation with Lyndon Miles, a consultant embryologist who spends his working life assessing sperm in the lab.
Most men will take the dog to the vet at the first odd sound, but leave their own health unchecked for years. For Men's Health Week (15 to 21 June 2026), we spoke to consultant embryologist Lyndon Miles about how to improve sperm quality through the everyday things you can actually control. The reassuring part, in his words: sperm renew roughly every three months, so the changes you make now can show up within a single cycle.
Your sperm is a window into your whole health
Lyndon's day job is fertility clinics and IVF, so he sees first-hand how often men are the overlooked half of the story. A male factor is involved in around half of fertility cases, yet the man is too often the last part of the picture to be properly looked at.
His bigger point is that a semen analysis is about far more than fertility. Sperm quality depends on blood flow, nutrition, hormones and sleep all working together, which is why it doubles as a sensitive read-out of your general health. The field is increasingly looking past the microscope at the whole person, because sperm health reflects what is happening across the rest of the body.
Start with your waistline
If you do one thing, Lyndon says, reach for a tape measure. It is the simplest health check there is, and it costs nothing.
The fat that matters most is visceral fat, the hidden kind packed around your internal organs that you cannot always see. It can lower your testosterone, which in turn lowers your sperm count, and it generates free radicals that can damage the DNA inside sperm. Research backs this up: higher visceral fat is consistently linked to lower testosterone and poorer sperm parameters.
Measured around the belly button, the NHS risk thresholds are a useful guide: under 94cm (37 inches) is lower risk, 94 to 102cm (37 to 40 inches) is raised risk, and over 102cm (40 inches) is high risk for problems like diabetes, low testosterone and heart disease. Those numbers are lower for men of South Asian, Chinese, African and Caribbean backgrounds. For men carrying excess weight, the encouraging news is that losing some can improve both fertility and wider health.
Move your body, but don't punish it
Exercise is one of Lyndon's pillars of male resilience, with one important caveat: move your body, don't punish it.
Moderate movement is the goal, and it does not mean training for marathons. Walking eight to ten thousand steps a day, or moderate sessions in the gym, improves mood, metabolism, hormone health and sperm quality. The problems start at the other extreme. Training two or three times a day, often stacked with pre-workouts and supplements that may not be needed, keeps the body under constant stress without enough recovery, and that takes a toll on your cells.
The testosterone "quick fix"
Scroll social media for five minutes and you will see adverts for testosterone. Lyndon's concern is that men increasingly reach for it as a quick fix for feeling tired or run down, without realising the trade-off.
Taking testosterone you do not actually need works against your fertility, because external testosterone signals the body to stop making its own. This is not a reason to ignore genuinely low testosterone. It is a reason to see a doctor who can assess and treat it properly, rather than self-prescribing from a website or the gym. The same goes for anabolic steroids.
Control the controllables
This is the phrase Lyndon keeps coming back to. You cannot change everything, but the levers that matter most are squarely within reach.
Prioritise sleep, which underpins your hormones, recovery and emotional resilience. Keep alcohol moderate and, if you smoke, stopping is one of the highest-impact changes you can make. Lean towards a diet that is mostly unprocessed or minimally processed food, without expecting perfection. And manage your digital world: constant doom-scrolling and never switching off from email keep you in a low-level state of stress that feeds poor sleep and poor eating.
His last point is the one men find hardest. Talk to people. Most blokes keep their group chats to football banter, but Lyndon's experience is that men who find the courage to open up are often surprised by how much support comes back.
What this means in practice
If you and your partner are thinking about a family in the next few years, the to-do list is refreshingly ordinary. Check your waist. Move more, but sensibly. Protect your sleep. Keep alcohol moderate and food mostly unprocessed. Step away from your devices. And keep off any testosterone you have not been prescribed.
Give it consistency. Because sperm take around three months to renew, sustained changes tend to show up in a test within a single cycle, not overnight.
Frequently asked questions
Can losing weight improve sperm quality?
For men carrying excess weight, yes. Visceral fat lowers testosterone and can damage sperm DNA, so losing some can improve both semen parameters and overall health. Because sperm renew about every three months, the benefits of sustained change often show within a single cycle.
What is a healthy waist size for men?
Measured around the belly button, under 94cm (37 inches) is lower risk, 94 to 102cm is raised, and over 102cm (40 inches) is high risk. The thresholds are lower for men of South Asian, Chinese, African and Caribbean backgrounds.
Can you exercise too much for fertility?
It is possible. Training very hard two or three times a day without enough recovery keeps the body under stress, which can work against you. Moderate, regular movement is best: think eight to ten thousand steps a day rather than punishing sessions.
Does cycling affect male fertility?
The concern is often overstated. There is no clear evidence of greater subfertility in keen or elite cyclists, and modern saddle design has reduced the pressure issues of the past. For most men, the benefits of regular exercise outweigh the small risk.
How long does it take to improve sperm quality?
Around three months. Sperm renew roughly every 74 days, so sustained changes to weight, sleep, alcohol, diet and stress can show up in a semen analysis within a single cycle.
Thank you to Lyndon Miles for sharing his expertise. The reassuring headline is that so much of male fertility sits within your control, and a few months of small, steady changes can make a real difference.
If you would like to know where you stand, our at-home sperm test with consultation gives you a clear picture of your reproductive health, analysed against World Health Organisation (WHO) guidelines and explained one-to-one by a registered fertility nurse.
