Here’s How Male Firefighters Can Protect Their Reproductive Health

By Melissa Lawlor CNM, FNP-C, Breastfeeding Medicine, FF/EMT, fire commissioner, deputy coordinator for First Responder Health and Wellness

Let’s turn up the heat on one health topic that may not make its way around the firehouse kitchen table: how those sweltering exposures on the job can impact your reproductive health as male firefighters.

Before we begin, let’s take a step back and brush up on some anatomy and physiology. Male reproductive anatomy and physiology encompass both internal and external structures that play a crucial role in the production, storage and transport of sperm. 

Additionally, these structures are responsible for producing and secreting male sex hormones, which are essential for maintaining the overall function of the male reproductive system. The external structures are: the penis, scrotum, testicles, and epididymis. The internal structures are: the vas deferens, ejaculatory ducts, urethra, seminal vesicles, prostate gland, and bulbourethral (Cowper’s) glands. 

Key male reproductive hormones include: testosterone, follicle stimulating hormone (FHS), luteinizing hormone (LH), inhibin B, and gonadotropin-releasing hormone (GnRH). 

How Heat Affects the Testicles

For this article, I’m going to focus on the effects of heat on “the boys.” Yep, the gonads. Your testicles. For the whole scientific process of spermatogenesis (i.e., healthy sperm production), I recommend hitting up YouTube. You can watch videos that dive deep into germ cells, diploids, haploids, meiosis and mitosis. Just know, normally, you produce millions of sperm daily, and the full spermatogenesis cycle takes between 64-74 days. 

Firefighters are frequently exposed to intense heat and chemicals, which can impact their fertility. Spermatogenesis requires the testes to be 35.6-42.8°F (2-6°C) cooler than the body’s core temperature. This is why the testes are located outside the body in the scrotum, maintaining an optimal temperature between 94°F (34.4°C) and 96°F (35.5°C). 

Prolonged exposure to high heat can decrease sperm count, increase the number of abnormal sperm, increase sperm clumping, and reduce sperm motility. All of these impact successful fertilization. 

It makes sense when you think about it. When you’re hot, your “boys” hang lower. When you’re cold, they pull up. The human body is fine-tuned like your Toyota Tacoma pick-up. 

How Heat Affects Sperm Quality

Heat exposure can also harm sperm quality through oxidative stress, a condition where reactive oxygen species (ROS) accumulate faster than the body can neutralize them, leading to sperm cell damage. 

The personal protective equipment (PPE) that firefighters wear, designed to shield them from extreme conditions, has low water vapor permeability and high insulation, limiting the body’s ability to dissipate heat. 

Firefighter research demonstrates elevated core body temperature following interior fire attack of about 101-102°F (38-39°C). This results in an increase in testicular temperature, further compromising sperm health. Consequently, heat stress can also lead to increased DNA damage in sperm cells. 

A 2021 study in the Reproduction and Fertility explored the effects of firefighting on semen quality. Twenty firefighters participated, with results showing that overall, their semen parameters were below the World Health Organization’s standards for fertility. 

Firefighters younger than 45 had a higher rate of abnormal semen (42 per cent) compared to those 45 and older (9 per cent). Higher rank and better hygiene (frequent handwashing and post-fire exposure showers) were linked to improved semen quality. More frequent fire exposures were tied to lower sperm count, volume and quality. Sperm clumping, which suggests reduced semen quality, was observed in 26 per cent of samples. 

A 2019 study in the American Journal of Epidemiology found that full-time firefighting is linked to a higher risk of male infertility. The main culprit seems to be heat stress on the genitals, caused by the intense heat firefighters face on the job and during chemical detox in saunas. 

It’s Getting Hot in That Gear

Firefighters also experience internal heat buildup from heavy physical activity while wearing turnout gear. Even slight, temporary increases in scrotal temperature can negatively affect sperm quality. 

Think about the moment you don your turnout gear. That familiar weight settles on your shoulders. Your mindset shifts to “I’m going to work.” Whether it’s a blazing fire with a black smoke plume you can see miles away, or a complex extended auto extrication, you’re ready for whatever comes your way. It might be cold and snowy, or the full triple H: hazy, hot, and humid. Sometimes you sweat so much in your gear that peeling it off feels like an entire workout on its own. 

Which brings me to rehab on the fire scene. Even in rehab, if you’re still in gear, you’re not really cooling down. Taking off your jacket but keeping your bunkers on doesn’t count – your “boys” are still roasting in there! To cool off properly, you’ve got to strip down, and let your body and your boys breathe. 

Healthy Habits for Reproductive Health

Adopting a healthy lifestyle is crucial for maintaining reproductive health and aiding recovery from heat-induced damage. This includes eating a balanced diet, regular exercise, not smoking, limiting alcohol, and abstaining from marijuana.

A Mediterranean diet, rich in antioxidants, can be especially beneficial. Antioxidant supplements like zinc, selenium, folic acid, coenzyme Q10, and vitamins C, E, D3, and K2, help combat oxidative stress and protect sperm from damage. By integrating these practices, you can enhance your overall reproductive health and support your body’s ability to recover from the effects of heat. Keeping your “boys” cool and your sperm in top shape isn’t just about dodging heat. 

Be a leader. Set an example. Take your rehab seriously: cool down, hydrate. Don’t skimp on frequent handwashing and post-incident showers. Living a healthy lifestyle goes a long way.