In our last article we discussed sleep within the fire service and hopefully provided some insight into how the job itself will affect their overall quality of sleep, which will lead to a number of health issues (type 2 diabetes, heart disease, hormonal imbalances, etc…), In this article our goal is to discuss how the poor sleep will affect the brain as well as hormones, and provide some simple strategies that may help improve your well being.

What are hormones? Simply stated, they are the engine for behavior and personalities; they affect everything from appetite to emotion to reproduction. The are created by glands in the endocrine system:
• Hypothalamus: regulate body temperature, hunger, moods, and controls thirst, sleep and sex drive
• Pancreas: produces insulin to help control blood sugar
• Thyroid: hormones associated with calorie burning and heart rate
• Adrenal: control sex drive and CORTISOL (stress hormone)
• Pituitary (Master gland): control other glands and makes the hormones that help with growth
• Pineal (thalamus): produce serotonin derivatives of melatonin
• Ovaries (only women): secret estrogen, testosterone, and progesterone
• Testes (only men): testosterone, sperm

Although each gland is important we are going to focus on a specific group of hormones that are often affected in the fire service: Cortisol, Melatonin, and Leptin/Grehlin. Why? Because they are often affected by the stress and lack of sleep / recovery that is associated within the fire service.

CORTISOL: The two faces…..

When we talk about sleep within the fire service, what we are really trying to say is “manage stress” because in reality we cannot change their sleeping habits while on shift, and if we try to change it we may be creating other issues because firefighters are very unique and very self regulating. For example, most firefighters will adapt to the shift schedule and call volume in the first 5 years. This naturally occurs and a very important process so they can handle the job in the future. Its part of the process……However, we can help provide alternatives on their days off.

Cortisol is your stress hormone and most people look at as bad, but in reality it can be helpful in certain situations because it is your “Fight or Flight” hormone. For example, if a bear were to attack you, you will either stay and fight or run (aka “Fight of flight). So we want your cortisol high during intense exercise and stressful situations, but low when you are not. Under the right circumstances, cortisol will help burn fat. If your workout consists of short intense exercise, cortisol will naturally increase along with growth hormone and catecholamine's which will lead to increased body fat to burn. We often recommend firefighters walk slowly or perform some type of low intensity exercise for 10 minutes to help cool down properly after an intense workout and to allow the cortisol to come down.

How does it work? As we sleep the body repairs first physically, then emotionally as we go through the sleep cycles. When we rise cortisol is high in the morning and as we go thru the day it will naturally come come down which help promote sleep. This is a very important concept to understand because the average population have heart attacks between 7am-10am, many experts believe this is due to the elevated cortisol. According the IAFF Redmond symposium, firefighters have heart attacks between 3pm-5pm. So it is safe to assume that a firefighter’s internal clock is almost the opposite then everyone else (they work from 6pm-6am, when everyone else sleeps).

Chronic elevated cortisol can be very destructive to the body and it leads to a number of health issues including depression, heart disease, and type 2 diabetes. If you are always “stressed” your brain will eventually shut off the goal oriented portion of your brain and for many you will crave junk food. Even worse, the brain becomes 60% more emotional and reverts back to a more primitive pattern which makes it difficult for a firefighter to put emotional experiences into context and produce control Why? Because cortisol will affect other hormones like melatonin, leptin, and serotonin. Even worse, the fatter you are the more cortisol you create. So it becomes a vicious cycle.

LEPTIN and GHRELIN: The appetite hormones…

How much does sleep impact your appetite? A LOT! In one study they looked at 1000 participants, and found that roughly 8 hours of sleep correlates with a lower body mass index, lower levels of ghrelin (triggers appetite), and higher levels of leptin (signals your body is full). Simply put, ghrelin increase hunger and leptin decreases hunger – which is important for weight loss.

HOWEVER, everything changes when we do not get good quality sleep. It is possible to become leptin resistant, but more important the brain does not function efficiently which leads to no drop in appetite and a slower metabolism which becomes a viscous cycle. If our bodies were in homeostasis then leptin is impacted by cortisol, for example when cortisol is low (you feel sluggish) leptin is usually high (not hungry) and vice versa, but when you have chronic sleep issues, cortisol will remain high (stressed) and leptin will remain low (hungry). In fact, if a firefighter is sleep deprived for 5 days in a row, they can gain up to 2lbs or for every poor night of sleep will add 300 calories to their daily intake

Shift work often affects sleep quality, and one study looked at how different shift schedules impact their quality of sleep. Researchers looked at 109 firefighters from 6 different departments in the southwest. The three schedules they studied were 24on/48off, 48on/96off, and Kelly. (1)

It was not a big shock to discover that 73% of firefighters reported poor sleep quality, but the 24on/48off associated with the best sleep quality and the Kelly schedule was the worse. Firefighters who worked second jobs reported even more significant sleep lose those who do not. Understand that a number of issues arise with shifts schedules (call volume, staffing levels, etc…) but based on this study it is easy to understand why depts. are switching to 24on/48off or 48on/96off.
So it is clear that the biggest issue is the constant sleep disruption which affects their circadian rhythms (internal clock). Let’s apply this knowledge to the life a firefighter:

Firefighter                               
Cortisol - Could be chronically high throughout the day leading to increase mood behaviors, weight gain, and poor sleep.

Heart Attacks (Time of day) - 3pm – 5pm

Work schedule - 30% of calls come between 7am – 5pm (downtime)

                             70% of calls come between 6pm – 6am (they work when everyone else is asleep)

Average Population
Cortisol - Usually  highest first thing in the morning and goes decreases throughout the day

Heart Attacks (Time of day) - 7am – 10am

Work schedule - 9am-5pm is common work schedule 

                            10pm – 6am – Sleep

Looking at this  we can easily see how the schedule of a firefighter is flipped upside down to the average population during their shift, and then they have to switch to a normal schedule on their days off – which is a constant back and forth which has an enormous affect on their circadian rhythm (aka cortisol & leptin/ghrelin).

MELATONIN: The Dark Hormone…..

Melatonin is called the “dark hormone” because it is produced in dark/night and help promote sleep. It will regulate the body’s sleep / wake cycle, and is suppressed by natural light, this is why sun light is a natural anti-depressant. Below is an example of our bodies natural circadian clock (FYI the circadian rhythm is actually longer than 24 hours):
2:00am – deepest sleep
4:00am – lowest body temperature
6:45am – sharpest blood pressure rise
7:30am - Melatonin secretion stops
10:00am – Highest alertness
2:30pm – best coordination
3:30pm – Fastest reaction time
5:00pm – greatest cardiovascular efficiency and muscle strength
6:30pm – Highest blood pressure
7:00pm – Highest body temperature
9:00pm – Melatonin secretion starts

Firefighters who may be suffering with mood disturbances tend to wake up earlier, which is often a sign that their melatonin is released earlier in the evening than those who do not suffer from mood disturbances. It is not uncommon to see the “Night Owl” waling around in the fire station at night. Why? My theory is that is the natural response to the job. Experienced firefighters generally will stay up late because they want to group their sleep together as much as possible. Why go to sleep at 9pm or 10pm when you know you will get a 911 call at 11pm and have to wake up. They generally adapt and stay up late so they can at least try and get 4 hours of sleep. This may create a delayed release of melatonin which is common in about 5-10% of adults.

I WOULD NOT recommend supplementing with Melatonin to help with your sleep. Again, it’s a hormone and it is not a good idea to supplement with it as it will eventually force the body to stop producing itself, which could lead to other health issues. YET, it may be beneficial with jet lag. When we travel multiple time zones our circadian clock will be disrupted and is often stuck in the city you left. So we recommend the following:
Traveling east: Morning Light + Evening Melatonin
Traveling West: Morning Melatonin + Evening Light

Overall, hormonal balance is very important to a firefighters well being, but unfortunately constant sleep disruptions will naturally affect them. It is vital to look at alternative approaches that may help improve their sleep which can help with their overall well being. Our next article will focus on improving on sleep quality via exercise, nutrition, and other resources.

TAKE AWAYS:
- Hormones are the engine for behavior and personality
- Constant sleep restrictions cause the brain to be 60% more emotional and reverts back to a more primitive pattern of activity – unable to put emotional experiences into context and produce control
- Sleep deprived for 5 nights in a row lead to 2lbs in weight gain
- 1 night of sleep deprivation can lead to 300 additional calories a day
- 7 hours is opitmal

(1) Billings J1, Focht W. J Occup Environ Med. 2016.Firefighter Shift Schedules Affect Sleep Quality. Mar;58(3):294-8