Low T and Cortisol: The Silent Killer

By John Hofman

Firefighters are often under a lot of stress, both physically and mentally. Stressful environments can increase inflammation in the body naturally, but it can also affect a firefighter’s hormonal response. The hormone testosterone is associated with body fat and muscle mass in men and has beneficial effects with regards to the cardiovascular system. Any type of deficiency will lead to increased body fat, less muscle, and increased chance of disease. One study performed in the United Kingdom showed that men with heart disease die sooner if their testosterone levels are low.  Another study found that low testosterone in men could increase the risk of developing Type 2 Diabetes (June 2003).

How Does the Job Affect a Firefighters Testosterone?

The physiological link between stress and testosterone is another hormone called cortisol. Cortisol is the body’s primary stress hormone, which increases sugar (glucose) in the bloodstream. It communicates with your brain to help control mood, motivation, and fear, and alters the immune system. When stress (either physical or physiological) is applied to the body, it produces cortisol (a flight-or-fight reaction), but if your body is continuously under stress, the body’s natural alarm system is always on. Continuous elevated cortisol levels are very dangerous and can lead to a number of health issues, including depression, heart disease, and stroke.

How can elevated cortisol levels and decreased testosterone levels affect a firefighter during the course of his career?  Over a 30-year career, a firefighter may develop poor sleeping habits (increasing cortisol), poor nutritional habits (reducing testosterone), and place their body under constant stress (increasing cortisol). All of these things will directly impact their health, but more importantly it will elevate their cortisol while reducing their testosterone. For example, 65 percent of calls are generally EMS related, but 75 percent of calls come between 6 p.m. and 6 a.m. Responding constantly to this type of call will impact firefighters’ sleep over the course of a 30-year career and create elevated cortisol levels. On the other hand, a simple structure fire could last 20 minutes or longer, with the average heart rate being 153; this constant stress load will impact their cortisol levels because during this prolonged time period testosterone production may be turned off to allow for the flight-or-fight response system to work properly. If we do not reduce the stress, then these elevated levels of cortisol will continue to exist, thus keeping our testosterone levels low.

Low testosterone can be very dangerous to firefighter health and wellness. Once you have checked your blood work, you can apply other simple methods to help increase your testosterone. Temporary blood sugar spikes will affect your testosterone levels, so avoid sugar, grains, and other foods that lead to an increase in blood sugar. Manage your glycemic index wisely, and include more high-protein quality fats into your diet. Exercise has been shown to help increase testosterone levels. High-intensity interval training that uses large muscle groups combined with adequate zinc levels increases testosterone.  For maximal testosterone response it is recommended that you lift heavy (85-95 percent, one-rep maximum) utilizing squats, deadlifts, and Olympic lifts. The most optimal rest period for testosterone production is 120 seconds between sets during resistance exercise. Optimal rest periods for growth hormone are 60 seconds. In other words, it is recommended that one vary their training program to include short rest periods for growth hormone stimulation and longer rest periods for increased testosterone production. (Sept. 2012)

What Can We Do About It?

It is nearly impossible to change the nature of the job, however we can approach it in a manner that will help protect against these elements. First, let’s first understand that if you do have low testosterone it does not mean you are at high risk of heart disease but rather poor health. There are a few things that can be done naturally to help you increase your testosterone while at the same time reducing the chance of heart disease.

The first step is to develop a basic medical screening program that includes a physical and simple blood draw. The second thing would be to educate our firefighters on what to analyze vs. just relying on the doctor. Cholesterol is usually the first thing people look at when talking about heart disease, but what about magnesium or vitamin D?

Firefighters are often in hot environments, so it is safe to say that they could develop a magnesium deficiency (magnesium is generally lost through sweating.) Also, many of the antiperspirants we use will prevent sweat loss but also contain aluminum chlorohydrate. Aluminum is antagonist to magnesium and reduces its absorption and our utilization of it.  One example of magnesium deficiency is during “Hell Week” for the U.S. Navy Seals, in which they have their zinc and magnesium levels reduced by 20-40 percent.  We could assume the same could be seen during a fire academy during the hot summer days. Magnesium deficiencies are often linked to low testosterone. (June, 2011)

Improved magnesium levels has shown  (April, 2011) to increase testosterone and also decrease inflammation, improve the cardiovascular system, lower levels of oxidative stress, and improve a firefighters sleep. More importantly is helps increase testosterone by enhancing vitamin D activity. It is recommended that you get 400-600 mg of magnesium daily. The most common method is by taking the supplement ZMA (Zinc, Magnesium Aspartate, which consists of 30mg of Zinc, 450 mg of magnesium, and 11mg of B6 and is taken at night to help promote sleep.)  Note: too much magnesium can be stressful to the kidneys, so follow the recommended amount.

Vitamin D is another common deficiency because most people do not go outside any more. Many studies have shown a relationship between low vitamin D and heart disease. Recently, a study published by Hormone and Metabolic research (2011) found that men with low levels of vitamin D had much lower free testosterone and higher estrogen levels. It appears that vitamin D inhibits aromatization in which testosterone is turned into estrogen. The Vitamin D Council recommends a blood level 0f 50ng /ml.

Finally, we need to look at our zinc. Zinc is important because it lower systemic inflammation and protects your heart. It is an anabolic element that affects tissue repair and healing. During sleep it aids in muscle growth. Zinc deficiencies have been correlated to low testosterone and a greater incidence of male menopause. It should be noted that the chief synergist of growth hormone is insulin, testosterone, zinc, and magnesium. The recommended daily allowance is 30 mg (ZMA). Note: Zinc can be toxic in high dosages, so follow the recommended amount.

Take Away

Understanding how fire suppression impacts a firefighters hormonal levels is just as important as knowing their cholesterol. Make sure the next time you receive your blood work you check your magnesium and vitamin D levels. Also, make sure to take some time to relax and rest properly. Simple solutions like knowing your hormonal levels can have a profound impact on your overall health.


“Low Testosterone levels are associated with an increased risk of diabetes, heart disease, and carotid atherosclerosis.” Diabetes Care 2003 June: Vol. 36. No. 6:20-30 Pilz, S., Frisch, S., et al. (2011).

“Effect of Vitamin D Supplementation on Testosterone Levels in Men.” Hormone and Metabolic Research.  43, 223-225

Cinar. V., Polat. Y., et a. (April, 2011). “Effects of Magnesium Supplementation on Testosterone Levels of Athletes and Sedentary Subjects at Rest and after Exhaustion.” Biological Trace Element Research. Volume 140, Issue 1, pp 18-23

Maggio, M., Ceda, G. P., Lauretani, F., Cattabiani, C., Avantaggiato, E., Morganti, S., Ablondi, F., Bandinelli, S., Dominguez, L. J., Barbagallo, M., Paolisso, G., Semba, R. D. and Ferrucci, L. (June 2011), “Magnesium and anabolic hormones in older men.” International Journal of Andrology, 34: e594–e600. doi: 10.1111/j.1365-2605.2011.01193.

Stokes. K.A., Gilbert. K.L., et al. (Sept 2012). “Different responses of selected hormones to three types of exercise in young men.” Eur J Appl Physiol

John HofmanJohn Hofman is the strength and conditioning coach for the Sacramento (CA) Fire Department, He oversees the Wellness Center; coordinates the department’s medical and fitness assessments; develops recruit fitness training, pre-employment medical and fitness evaluations; and assists the department’s 20 certified Peer Fitness Trainers. In addition, he is the strength and conditioning coach for the California Regional Fire Academy, Sierra Fire Technology Program, Rocklin Fire Department, and South Placer Fire District. He also consults with the Fire Agency Self-Insurance System of California. Visit John’s Web site at www.firefighterfitnessonline.com.

In an effort to help keep firefighters safe Strength & Conditioning Coach John Hofman authored Beyond the Turnouts: A Comprehensive Guide to Firefighter Health & Wellness — where he combined the latest research and his years of experience developing firefighter health and wellness programs within the fire service. CLICK HERE for more info about the book.

No posts to display