THE BIOLOGY OF SLEEP
Every person needs a different amount of sleep to awaken feeling refreshed. Individual sleep requirements are genetic and may be hereditary. Scientists consider six to 10 hours of sleep a normal range, with most people requiring 7.5 to 8.5 hours of sleep in a 24-hour period. At least four to five hours of uninterrupted core sleep is necessary to maintain minimum performance levels. Sleep requirements may change slightly with age and can be affected by general health. Illness, stress, and depression cause the body to require more sleep to heal and recuperate.
WHAT IS SLEEP DEPRIVATION?
Sleep deprivation occurs when a person does not get sufficient amounts of quality sleep. Work demands, family life, and lifestyle choices may cause a person to sleep fewer hours than his body needs to maintain wakefulness and energy levels. In the Fire Service most of us to Shift work and have to interrupt the body's natural wake/sleep cycle. Over time deprivation of sleep can have both an acute and cumulative effect on our bodies and minds.
A study at the University of Chicago, rats kept from sleeping became sick and died after two and a half weeks. Sleep-deprived rats that became ill but were then allowed to sleep recuperated fully
THE EFFECTS OF SLEEP DEPRIVATION
Sleep loss is cumulative and creates a sleep debt. Larger sleep debts require greater amounts of restorative sleep to return the body and mind to normal, rested levels. Sleep deprivation affects mental processes and intellectual abilities. It reduces performance on challenging tasks and negatively affects psychomotor skills. Mood, productivity, and communication skills suffer. Extended periods without sleep may cause hallucinations and paranoia.
Physical and mental performances are not the only casualties of sleep deprivation. Even a minimal loss of sleep impacts general health. Chronic lack of sleep can contribute to serious health problems and even shortened lifespan. In a 1983 study at the University of Chicago, rats kept from sleeping became sick and died after two and a half weeks. Sleep-deprived rats that became ill but were then allowed to sleep recuperated fully.
Lack of sleep may slow glucose metabolism by 30 to 40 percent and increase levels of the stress hormone cortisol. Sleep deprivation has also been linked to inadequate levels of the hormone leptin. Leptin signals the body to stop eating when it's full. Decreased levels of leptin lead to increased carbohydrate cravings and eating.
Other effects of chronic sleep deprivation include:
- Depression and mood swings
- Gastrointestinal dysfunction
- Adult-onset diabetes
- Menstrual and infertility problems
- Increased use of drugs and alcohol
- Impaired sexual function
- Less satisfaction in personal and domestic pursuits
- Increased appetite and weight gain
- Personality changes, particularly loss of humor and increased ill temper.
COUNTERMEASURES AND COPING STRATEGIES
"Firefighters need to get an adequate amount of uninterrupted sleep every off-duty night"
Quality sleep is the primary weapon in the battle against sleep deprivation. Firefighters must take advantage of opportunities for sleep, both on and off duty. Sleeping areas at home and at the fire station should be quiet and dark, and the room temperature should be cool. A comfortable, good-quality mattress is a must. Invest in comfortable bedding and pillows as well. Good sleep habits are essential. Firefighters need to get an adequate amount of uninterrupted sleep every off-duty night. Going to sleep and waking up at the same times every day, even on weekends, is important for maintaining the body's natural rhythms.
Other tips for quality sleep include the following:
Avoid eating, reading, and watching TV in bed.
Restrict caffeine intake, and avoid caffeinated drinks at least six hours before bedtime.
Eat healthful foods. Do not eat large meals within four to five hours of sleeping.
Do not use alcohol to induce sleep. The effects of alcohol-induced drowsiness last only a few hours and cause poor-quality sleep.
Avoid long-term use of over-the-counter sleeping pills. Habitual use can reduce effectiveness and lead to addiction.
Reduce life stress as much as possible.
Use relaxation techniques to relieve stress and invite sleep.
Exercise, but not more than four hours before bedtime. For 24-hour shift workers, outdoor exercise during daylight hours can help the body maintain natural biological rhythms and increase sleep quality off-duty.
"Napping is an effective coping strategy"
Daytime sleep after a night shift is essential to staying well rested, but trying to sleep when the rest of the world is awake can be challenging at best. The shift worker must emphasize to friends and family the importance of restorative sleep. Go as far as having daytime sleep scheduled on the family calendar along with ballgames, school meetings, and other activities.
Napping is an effective coping strategy that can be used in anticipation of a long night or during extended operations. Naps as short as 20 minutes can be effective. Two-hour naps during around-the-clock operations are highly restorative.
Melatonin may help promote better sleep, particularly during the day. However, this supplement is not FDA-approved, and current research is contradictory on short-term and long-term effects.
People who are regularly unable to sleep should consult their physicians to rule out underlying health problems. Doctors may also be able to prescribe medication to help with sleep. Sleep disorders can be aggravated by shift work. Shift workers with diagnosed sleep disorders need to work closely with their physicians to effectively manage their disorder.
Koester, Robert J. Fatigue: Sleep Management During Disasters and Sustained Operations. DbS Productions, 1997.
Maas, Dr. James B. Power Sleep. HarperPerennial, 1998.
Moore-Ede, Martin, M.D., Ph.D. The Twenty-Four Hour Society. Addison-Wesley Publishing Company, 1993.
NIOSH.Publication 97-145. "Plain Language About Shiftwork." 1977