There are a lot of articles out there about how women can improve their fertility. But if you’re a man and you and your partner are trying to conceive, it’s worth your time to enhance your fertility, too. You’re half of the equation — and fertility in men has been steadily declining over the last few decades[*]. 

The good news is that you have a lot of control over your fertility levels. With a few simple (but powerful) lifestyle changes, you can make night-and-day changes to your fertility,  without any trips to the clinic or side effect-laden pharmaceuticals. 

Years ago, doctors told my wife Lana and me that we would never have kids. We decided to take matters into our own hands. We even wrote a book, the Better Baby Book, that’s about boosting fertility in both men and women. Today, we have two healthy kids, as well as a lot of knowledge about how to increase your chances of conceiving, even against all odds. 

Here are three of the most valuable lifestyle changes you can make to improve your fertility. 

Start by Testing

Data is an essential part of biohacking. You want to be able to track your improvements to see what’s working for you and what isn’t. 

That’s why I recommend starting off with a baseline fertility test and then testing every couple of months to see how your numbers have changed. 

I talk a lot about how much I like in-home testing. I think it’s ridiculous that you have to get a (very expensive) note from your doctor in order to get basic information about your own body. 

Fortunately, more and more companies are offering advanced medical tests that you can do from home, and fertility is no exception. 

My preferred company is Legacy. You order a test, they ship you a sample kit, you send them back a sample of semen, and they run a comprehensive fertility test and return your results in a few days. No getting a doctor’s note, going into a clinic, asking the elderly nurse for a magazine — you get to skip the worst parts of fertility testing. 

However, you decide to test your fertility, make sure you get a baseline. Then you can tweak your lifestyle and see what actually moves the needle. 

Once you have a baseline, try these tools to improve your fertility. 

1. Switch to Boxers

It turns out that the timeless “boxers or briefs” question can have a major impact on your fertility. 

Do you know how your balls shrink when you get cold? 

That happens because your testes are incredibly sensitive to temperature. Changes of even a few degrees will impact your semen quality and sex hormone production. When it gets cold outside, your testes move closer to your body because your body heat keeps them at the right temp. 

But if you’re wearing tight underwear or tight pants, your balls are going to be close to your body all the time, which can make them overheat. And it turns out that can impact fertility more than you might expect. 

A 2018 study of 656 men found that wearing boxers was associated with 25% higher sperm concentration and 17% higher total sperm count, compared to men who wore briefs[*]. 

So if you’re wearing briefs or tight pants and you’re trying for a baby, switch to something with more breathing room. It can make a surprisingly large difference in your semen quality. 

2. Hack Your Sleep

Sleep is one of the pillars of good health, and that’s doubly true when it comes to fertility. 

• A 2019 study found that, compared to men who slept 8 hours a night, men who slept less than 6 hours a night had a 32% decrease in infertility, and men who slept more than 9 hours a night had a 25% decrease in fertility (oversleeping is often a sign of low sleep quality)[*]. 
• A 2017 study found that men who sleep shorter or longer than 7-8 hours produce more anti-sperm antibodies, immune system proteins that damage sperm motility and decrease your ability to conceive[*]. 
• Poor sleep also dramatically decreases your testosterone levels, which makes you less fertile[*]. 

Deep, restorative sleep is essential for fertility. If you’re struggling to get a good night’s sleep, here are my three quick recommendations:

• Blackout your room. Even a small amount of nighttime light exposure suppresses melatonin, the hormone that makes you sleepy, and tanks your sleep quality as a result[*]. Get a set of light-blocking curtains and put electrical tape over any blinking lights (WiFi routers, alarm clocks, electric toothbrush stands, etc.). You want your room to be so dark at night that you can’t see your hand in front of your face. It’s a simple hack and you’ll be amazed by the difference it makes in your sleep quality. 
• Take a quality sleep supplement. 400 mg of magnesium glycinate and 0.3 mg of melatonin a night is a good place to start (or you can take Sleep Mode, which replaces magnesium with L-ornithine and works well for more heavy-duty sleep issues). 
• Download F.lux. It’s a free program that removes melatonin-suppressing blue light from your computer after sunset. This is especially useful if you’re on your computer late at night; it’ll decrease your blue light exposure and normalize your circadian rhythm, even if you’re working or watching Netflix right before bed. You can download F.lux for free and start using it tonight. 

3. Work Out Hard and Fast (and Rest Afterward)

Working out is one of the best things you can do for your body in general, and the right kind of exercise is particularly good for boosting fertility. 

According to research, lifting heavy things and sprinting are the two best ways to increase fertility. Basically, you want to do intense, short-term exercise and then rest afterward. 

• A 2018 study of 1200 infertile men found that those who began lifting weights consistently saw significant gains in fertility. They saw a decrease in inflammation and oxidative stress in their reproductive systems, as well as increased semen quality and a greater number of pregnancies[*].
• Another study found that consistent strength training or high-intensity interval training (HIIT) followed by rest improved semen quality and overall fertility in men[*]. 

Consistent long-distance running, on the other hand, seems to negatively affect fertility. Several studies have found that endurance athletes actually have lower semen quality and decreases in testosterone and other sex hormone production[*]. 

That’s not to say that you shouldn’t do cardio — by all means, go for runs if you enjoy them — but make sure you’re also doing short, intense exercise like lifting or HIIT, and always rest after your workout. The authors suspect that part of the problem with long-distance runners is that their bodies are under consistent, low-grade physical stress without periods of recovery, which may contribute to fertility problems[*].

Test Your Fertility Every 2-3 Months

Spermatogenesis — the creation of new (and hopefully strong) sperm — takes about 65–75 days, so you’re not going to see improvement immediately. The sperm in your ejaculate right now started their journey two or three months ago, so they were influenced by your lifestyle at that time. To evaluate your progress, you want to do a fertility test every two or three months. 

Remember, infertility is a functional diagnosis. That means it’s based on whether or not a couple is actually able to get pregnant—not on sperm counts or hormone levels. So while a semen analysis will give you a lot of data about your sperm health and how it correlates to your chances of conceiving naturally, it won’t come back stamped FERTILE or INFERTILE. Fertility is more complex than that and involves your partner’s fertility health, among other factors.

That said, you can make huge strides in your fertility with a few simple changes to your lifestyle. Try the hacks I talk about in this article and work with your partner to improve your fertility together. You have more power to change your biology than you might think.