The brain needs sleep to perform nightly maintenance — for firefighters and everyone else

At the top of the article: USFS photo.

The brain uses a quarter of the body’s entire energy supply, yet only accounts for about two percent of the body’s mass. So how does this unique organ receive and, perhaps more importantly, rid itself of waste? New research suggests it has to do with sleep.

In the TedMed video above, neuroscientist Jeff Iliff explains the connection between sleep and brain function.

A study of almost 7,000 firefighters from municipal fire departments found that 37 percent screened positive for common sleep disorders, including obstructive sleep apnea, insomnia, restless leg syndrome, and shift work disorder.

The researchers found that compared with sound sleepers, those with a sleep disorder were about twice as likely to have a motor vehicle crash, to nod off while driving, and to have cardiovascular disease or diabetes. They were more than three times as likely to suffer from depression and anxiety.

Wildland firefighters usually work 8-hour shifts —  except when they don’t. While on fires their shift schedules and sleep routines are often disrupted. The 8-hour shift can be extended to 12 to 16 hours, and their usual sleeping and waking times may be changed and sometimes shortened; not unlike the jet lag of traveling to a different time zone. The first shift on a fire may be longer than 16 hours and a crew used to working during the day can be placed on a night shift.

A firefighter sleep study conducted by the Missoula Technology Development Center between 2006 and 2008 found that sleep deprivation contributed to fatigue, stress, and impaired performance of Incident Management Team members.

I talked with pilots and other personnel that traveled with an air tanker to a new assignment. Depending on their original location, they flew across two to four time zones and after arrival, they started work about two hours earlier than usual. So the net change was four to six hours worth of jet lag when taking the new work schedule into account. After a couple of days at the new site two crewmembers told me that they were really tired, even though they were not physically working much harder than normal. Their supervisor eventually recognized this and made sure they got a day off.

That kind of disruption in a work/sleep/wake schedule is common among wildland firefighters, especially those that travel long distances to an assignment. It is possible that wildland fire managers do not recognize this and the negative effect it can have, or if they do, may feel there is little they can do to mitigate the problem.

Crew supervisors and incident management teams should at least strive to give firefighters an opportunity to get an adequate amount of quality sleep.

We have written before about the importance of sleep for wildland firefighters. Articles on Wildfire Today tagged “sleep”.

Study links firefighter accidents to sleep problems

fire Whiskeytown National Recreation Area
An incident base at Whiskeytown National Recreation Area in California, 2009. Photo by Carol Jandrall.

A study of almost 7,000 firefighters from municipal fire departments found that 37 percent screened positive for common sleep disorders, including obstructive sleep apnea, insomnia, restless leg syndrome, and shift work disorder.

The researchers found that compared with sound sleepers, those with a sleep disorder were about twice as likely to have a motor vehicle crash, to nod off while driving, and to have cardiovascular disease or diabetes. They were more than three times as likely to suffer from depression and anxiety.

The study, published in the Journal of Clinical Sleep Medicine, said that nationwide 61 percent of firefighter on-duty fatalities are caused by heart attacks or motor vehicle crashes.

National Interagency Fire Center data that we reported for 1990 through 2014 shows that 45 percent of the wildland fire fatalities were from vehicle accidents or medical issues.

Wildland firefighter fatalities 1990-2014
Wildland firefighter fatalities, 1990-2014. Data from NIFC, compiled by Wildfire Today.

Most, 97 percent, of the 7,000 firefighters in the study worked extended shifts of at least 24 hours. Wildland firefighters work 8-hour shifts —  except when they don’t. While on fires their shift schedules and sleep routines are often disrupted. The 8-hour shift can be extended to 12 to 16 hours, and their usual sleeping times may be changed and sometimes shortened; not unlike the jet lag of traveling to a different time zone. The first shift on a fire may be longer than 16 hours and a crew used to working during the day can be placed on a night shift.

The municipal firefighters in the study work very different schedules from their brothers and sisters in wildland fire, so a direct comparison of sleep disorders and accidents is probably not valid, but this issue should be watched closely. Crew supervisors and incident management teams should, at least, see that firefighters have an opportunity to get an adequate amount of quality sleep.

The same journal that published this study has another interesting one titled, “The Association between Sleep Disturbances and Depression among Firefighters: Emotion Dysregulation as an Explanatory Factor”.

How much sleep do tactical athletes need?

sleep firefighter
Tom Sadowski, El Cariso Hotshots, 1972. Photo by Bill Gabbert.

Charles Palmer, an associate professor at the University of Montana who studies performance psychology of wildland firefighters, has called them “tactical athletes”. Mr. Palmer, who spent 20 years as a firefighter and smokejumper, has said:

These aren’t people who ride around in trucks and squirt water on stuff — this is really demanding from a lot of different angles. You travel around, you have to perform, they’re getting very little downtime, they have nutritional challenges … physically you have to perform really well.

A study of wildland firefighters during suppression activities in Spain found that heart rates ranged from 116 to 133 beats per minute depending on the length of the work. Researchers in Australia measured heart rates of firefighters operating hand tools that were 95 percent of their predicted maximal.

When we read an article at the Monday Morning Quarterback about managing the sleep of professional football players, we could’t help but make the comparison between those athletes and the ones who fight wildfires for a living.

According to the piece by Jennie Vrentas, an increasing number of NFL teams are emphasizing an adequate amount of sleep for their players. Below are some excerpts from the article:

A good night’s sleep is directly tied to key factors such as reaction time, mental alertness, muscular recovery and converting what you’ve recently learned into memory. That’s why the science of slumber has become one of the hottest trends in the NFL: Teams are no longer leaving it to chance that their multimillion dollar investments will manage sleep cycles all on their own.

The Dolphins and Patriots have dark rooms at their practice facilities so players can take naps. Eagles players fill out a morning questionnaire on their tablets, self-reporting how long and how well they slept the previous night.

If you run on four hours of sleep a night for a week, it’s the same as drinking a six-pack and then going to work.

“The average athlete probably needs eight to nine hours of sleep, given their physical demands,” [Washington team physician Anthony] Czeisler says, and even more if you can get it. “I wish I could say there’s a shortcut, but if you are going to be a professional athlete, you need to pay careful attention to sleep.”

A single all-nighter, or a week spent getting just four hours of sleep a night, can make one’s reaction time nearly three times slower.

The article refers to studies completed on football and basketball players, but there has also been research on how sleep affects wildland firefighters. In a study of firefighters in Australia during a four-day simulation of an assignment on a wildland fire, it was found that after two nights of being restricted to four hours of sleep their performance on a hand-eye coordination task declined. However their work output remained about the same even after consecutive nights of restricted sleep.

In a related study in Australia, Grace Vincent, a PhD student at Deakin University reported:

The firefighters report [that while working on actual fires they get] only about four to five hours sleep per night. They have trouble sleeping due to other people snoring in locations such as cabins, tents or the floor of school gyms.  Some are simply so wired after spending the whole day in emergency-mode, that they can’t switch off.

This is consistent with research in the United states, in Technology and Development Publication, Wildland Firefighter Health and Safety Report, Issue Number 13, Summer 2009:

…Sleeping in fire camp can be a challenge. Noise from generators, vehicles, and other firefighters all contribute to sleeplessness. Because almost all wildland firefighters need to sleep either in fire camps or in spike camps, they sleep in tents, on the ground, and in hot, smoky, and dusty conditions. Shift work interferes with sleep, especially for those on night shift.

Sleep log data were collected on members of five incident management teams at fire camps in California and Montana during 2008. [Note from Bill: this data appears to be from overhead team members in fire camp, not “tactical athletes” out in the field.] Data for 140 team members (36 percent female, 64 percent male) indicated that they averaged 6.1 hours of sleep, ranging from 3.5 to 9.0 hours per night. On average, team members went to bed at 9:30 p.m. They reported being awakened an average of 2.2 times per night, awakening from zero to six times per night. When team members were asked to rate the quality of their sleep, the average was 6.6 on a 10-point scale. Nearly one-fourth (23.8 percent) reported feeling tired when they woke, while 53.6 percent felt somewhat rested, 20.2 percent felt rested, and 2.4 percent felt very rested.

Eight hours of rest between work periods is inadequate because only 50 to 75 percent of the rest period is devoted to sleep. Thus it is advisable to have longer rest periods (10 to 14 hours) so workers have time for adequate sleep.

Total sleep deprivation for 1 week has led to cognitive impairment when work requires multitasking. In driving, accidents increase as sleep duration is decreased. In tasks requiring judgment, risky behaviors emerge when sleep is limited to 5 hours per night.

Behavioral alertness and a range of cognitive functions, including sustained attention, and working memory deteriorate when nightly sleep is limited to between 4 and 7 hours. Decisionmaking skills, such as the ability to assess risk, assimilate changing information, and revise strategies to solve problems based on new information are likely to suffer.

Eight hours of rest between work periods is inadequate because only 50 to 75 percent of the rest period is devoted to sleep. Thus it is advisable to have longer rest periods (10 to 14 hours) so workers have time for adequate sleep.

What about naps?

The same publication recommended naps when possible, but the length is important:

Naps restore alertness, enhance performance, and reduce the risk of mistakes. To avoid waking up groggy and exhausted, workers should nap for 20 to 30 minutes OR for longer than 90 minutes. A one-hour nap places you in the middle of deep sleep, making it difficult to wake up. You will be disoriented and clumsy, might make poor decisions, and could be at risk of an injury. A 20-minute nap ends before you descend into deep sleep; a 90-minute nap catches you rising out of deep sleep.