The Impact of High Stress Environments on Physical Recovery and Health in Firefighters

By, Zach Interewicz – O2X On-Site Specialist

It is commonly known that firefighters endure both physical and mental stress when performing firefighting tasks and operations. The occupation is recognized to be unpredictable, hazardous, and demanding. Heat stress, from the fire itself and from personal protective equipment (PPE) can affect normal physiological function from a mental and physical standpoint. Managing stress is important for longevity and overall health in the fire service. If stress cannot be managed properly through healthy interventions (adequate sleep, nutrition, exercise and mindfulness/breathwork), there is an elevated risk of being predisposed to negative health consequences from chronic stress exposure. Therefore, this article aims to inform the reader on the stress impact on firefighter’s health and recovery while also providing some interventions to manage stress and improve health measures.

Impact of Stress

Stress is something that everyone must endure in their lifetime. Stress can be defined as the body’s response to physical, mental, and emotional pressure. Stress can be caused by your physical environment, social interactions/relationships, financial status, organization/work, life events, lifestyle choices, and physiological state. In an emergency or dangerous situation, the sympathetic nervous system (SNS) becomes activated and elicits the fight or flight response. This results in a cascade of hormonal responses, one of them being a release of cortisol. Cortisol is a glucocorticoid, a steroid hormone that is secreted by the adrenal cortex. Glucocorticoid receptors are present in almost all tissues in the body. Therefore, cortisol can affect nearly every organ system including the nervous, immune, musculoskeletal, cardiovascular, respiratory, integumentary (hair, skin, nails), and the reproductive systems. (Thau et al,. 2023). Cortisol plays many important roles including regulating the body’s stress response, controlling the metabolism of carbohydrates, fats, and proteins, suppressing inflammation, regulating blood glucose, regulating blood pressure, and aids in controlling the sleep-wake cycle.

Cortisol is widely known as the stress hormone. Although small increases in cortisol can be a beneficial, too much cortisol in the bloodstream can cause a number of health issues including: high blood sugar, anxiety, depression, fatigue, gastrointestinal upset such as constipation, bloating, or diarrhea, increased abdominal fat, diabetes, headache, heart disease, cancer, high blood pressure, lowered immunity, decreased inflammatory response, irritability, memory and concentration problems, sleep difficulties, weight gain, and slow recovery from exercise.

Firefighters are chronically exposed to acute heat stress. Firefighters wear equipment that is very thick, multi-layered, and cumbersome. This personal protective equipment (PPE) is beneficial because it provides protection from environmental hazards and injury. However, the equipment is also detrimental in that it has limited air and water vapor permeability, which prevents wet and dry heat loss to the external environment. The limited permeability creates a microclimate with its own temperature and relative humidity. This microclimate prevents adequate thermoregulation in scenarios that lend themselves to extreme exertion, high ambient temperatures, and high relative humidity (Cheung et al., 2000). It is known that exercise in the heat increases plasma and serum cortisol levels when compared to exercise in a normothermic condition. Additionally, salivary cortisol increases during firefighting drills to reflect the state of thermal stress (Brenner et al., 1997).

Along with the acute heat stress that occurs during firefighting operations, firefighters are also exposed to other stressors that can affect cortisol levels. Some of these include 24-hour shift work which can affect sleep schedule and cycles, sedentary lifestyle choices, eating a highly processed diet, and social stress from work, family, and friends. Although we cannot eliminate the heat stress that firefighters are exposed to or their 24-hour shift work schedule, we can take a series of health countermeasures to negate the effects of stress and cortisol levels. These countermeasures include adequate sleep, exercise, proper nutrition and hydration, and stress regulating activities.

Impact of Sleep

Studies have shown that sleep deprivation can influence cortisol levels compared to control groups where they received adequate sleep time (Leproult et al.,1997). It’s purported that even partial acute sleep loss delays the recovery of the hypothalamo-pituitary-adrenal (HPA) axis, which helps regulate cortisol levels from early morning circadian stimulation and is thus likely to involve an alteration in negative glucocorticoid(cortisol) feedback regulation. Sleep loss could affect the resiliency of the stress response and may accelerate the development of metabolic and cognitive consequences of cortisol excess. Striving for a good night’s sleep, somewhere between 7-9 hours is a healthy recommendation for most adults. Achieving adequate sleep in the fire service is sometimes challenging due to shift work schedule, frequency of calls, and suboptimal sleep environments at the fire station. Unfortunately, firefighters have reported disrupted sleep as a result of shift work, with an average of 5 hours and 21 minutes (Gonzalez et al., 2024). Some tips to achieve better sleep at night include: limiting caffeine ~8 hours before bed, limit late night blue light exposure (cell phones, TV’s, computer screens), create a dark and cool temperature environment, and the use of calming sounds or white noise to block out outside noises that can be distracting to falling asleep.

Impact of Nutrition

There are numerous health benefits to exercising regularly. Exercise is purported to reduce levels of the body’s stress hormones, such as adrenaline and cortisol. It also stimulates the production of endorphins, chemicals in the brain that are the body’s natural painkillers and mood elevators. The World Health Organization (WHO) suggests that adults between the ages of 18-65 years should participate in at least 150–300 minutes of moderate-intensity aerobic physical activity, 75–150 minutes of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate and vigorous-intensity activity throughout the week, for substantial health benefits. It’s also suggested adults should also do muscle-strengthening activities at moderate or greater intensity that involve all major muscle groups on 2 or more days a week, as these provide additional health benefits. It’s also recommended that when one is conditioned enough, more physical activity can be introduced for further health benefit. As tactical athletes, firefighters should strive to be well-rounded in terms of their physical strength and conditioning. This means one should strive to enhance all physical characteristics including muscular strength, muscular endurance, speed, power, aerobic conditioning, anaerobic conditioning, and mobility/flexibility.

Ultra Processed Foods (UPF) are quite common in the Western Diet. UPF are defined as “formulations of ingredients, mostly of exclusive industrial use, which have little or none of the food intact and are typically created by a range of industrial techniques and processes”. Most UPF are energy-dense products high in added sugars, saturated and trans fatty acids and sodium and low in protein, fiber and certain micronutrients including potassium, magnesium, vitamin C, vitamin D, zinc, phosphorus, vitamin B12 and niacin. The global growth in the prevalence of noncommunicable diseases in recent years has been accompanied by an increase in the consumption of UPF. Known to be hyperpalatable, economic, and ready-to-eat, increased consumption of UPF has already been recognized as a risk factor for several chronic diseases. Current evidence highlights the adverse health effects of UPF characteristics, not only due to the nutrients provided by a diet rich in UPF, but also due to the non-nutritive components present in UPF and the effect they may have on gut health. (Tristan et al. 2024) Dietary choices influence cortisol levels. For instance, diets high in refined carbohydrates and sugars can lead to hyperinsulinemia, driving HPA axis activation and subsequent cortisol release. A cross-sectional study examined the dietary habits of voluntary firefighters and found they consumed lower amounts of fruits, vegetables, whole grains, and fiber; while intaking higher amounts of refined sugars (Kadiwar et al,. 2021).

Knowing the adverse health effects of a highly or ultra processed diet, firefighters and other tactical athletes should focus on getting more whole and unprocessed foods into the diet. This includes whole grains like brown rice, quinoa, and oats, lean protein coming from chicken, fish, turkey, eggs, and lean beef; fruits and vegetables, and healthy fats such as olive oil, avocados, seeds, and nuts to name a few. Firefighters should aim to have an energy-balanced diet that provides the proper nutrients to fuel performance and maintain a healthy metabolic profile.

Utilizing Breathwork

When searching for a simple stress management approach, the ancient practice of breathwork stands out for its accessibility and effectiveness. This practice is often referred to as Pranayama; the ancient yogic practice of controlling your breath. This method, centered on the conscious control of breathing, serves as a powerful tool for enhancing both mental health and physical wellbeing.

Breathwork provides a wide range of health benefits, including improved moods, reduced high blood pressure, and enhanced relaxation. It can also be effective in managing symptoms of chronic conditions like COPD and asthma, improving cognitive functions such as alertness and memory, and fostering creativity and quality sleep. Additionally, breathwork has been found to reduce anxiety and depression, and increase heart rate variability, indicating improved fitness and mental health.

References:

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9. WHO Guidelines on Physical Activity and Sedentary Behavior. Geneva: World Health Organization; 2020. RECOMMENDATIONS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK566046/

About O2X On-Site Specialist Zach Interewicz:

Zachary Interewicz is an O2X Human Performance On-Site Specialist with the Frederick County Fire Department. In this capacity, Zach works closely with firefighters to optimize their physical and mental performance, ensuring they are well-prepared to meet the demands of their challenging profession. His background in strength and conditioning, coupled with his previous work with the U.S. Army’s 10th Mountain Combat Aviation Brigade, equips him with valuable insights into human performance under high-stress situations.

Before joining the Frederick County Fire Department, Zach honed his skills in various roles, including serving as a strength and conditioning/rehab specialist in hybrid Physical Therapy and Performance Facilities. His time as the assistant strength and conditioning coach for the Wilkes-Barre/Scranton Penguins provided him with hands-on experience in elite sports training, further enhancing his expertise in optimizing human performance. Zach’s diverse professional background underscores his commitment to helping individuals achieve their peak performance levels, whether in sports or high-stakes professions.

Zach’s academic journey reflects his passion for understanding human performance. He holds a Master of Science degree in Exercise Science with a concentration in sport and exercise conditioning, as well as a Bachelor of Science degree in Exercise Science from East Stroudsburg University in Pennsylvania.

About O2X Human Performance:

O2X Human Performance provides comprehensive, science-backed programs to hundreds of public safety departments, federal agencies, and the military. O2X works with clients to elevate culture, improve mental and physical wellbeing, support healthy lifestyles, and reduce healthcare costs associated with injuries and illnesses. Driven by results and cutting edge research, O2X programs are designed and delivered by a team of Special Operations veterans, high level athletes, and hundreds of leading experts in their respective fields of human performance.