I read a recent article in the FAA Aviation News, authored by Dr. Melchor Antunano. The article is titled, "Fatique Can Put You To Rest". I was so impressed by the serious nature of its content, that I thought I would included in my Aviation Forum, here at Landings.com. But first, consider the following paragraph:

There is an old axiom in aviation that, "Flying is characterized by countles hours of boredom, followed by moments of sheer terror". Before you read on, pretend for a moment that you are a multi-engine pilot flying a light twin. You didn't sleep too well last night (or for that matter, the night before), but you managed to chug down a couple of cups of coffee before you climbed into the cockpit. Internally, you admit that you are not feeling on-the-ball, but decide to depart anyway. You have just been cleared for takeoff by the tower. Throttle's forward... air speed is alive... rotation... positive rate and gear up. You are 400 feet above the runway when you hear a loud boom, followed by an adverse yaw. Your airspeed is dropping and adrenaline is pumping. You have to think fast and act fast, but pull back on the wrong prop... and you are a dead man. Got your attention? Then take the following very seriously.

Fatigue, a normal physiological response of the human body to sleep loss and circadian rhythm disruption, is characterized by decreased physical and mental efficiency.

Common signs and symptoms of fatigue include sleeplessness, overall discomfort, irritability, depression, apathy, physical an emotional isolation from others, loss of appetite, slurred speech, visual fixation and impaired visual perception, decreased alertness, difficulty concentrating, slowed reaction time, need for increased sensory stimulation to react, impaired short-term memory, poor judgment, loss of accuracy and control smoothness, unawareness of errors, and responses to become increasingly more dependent on previously acquired habits (good or bad).

In these manifestations can be aggravated by individual exposure to other stressors, including low barometric pressure, noise, vibration, linear and angular acceleration (G forces), high ambient temperature, and low humidity. Furthermore, self-imposed stressors, such as poor physical fitness, inadequate diet or nutrition, inadequate hydration, excessive body weight, drug and alcohol use or abuse, use of medications, excessive caffeine consumption, and tobacco use can predispose you to becoming fatigued..They also can aggravate fatigue.

Sleep is a period of rest for the body and mind, during which bodily functions are partially suspended and consciousness is temporarily interrupted. Sleep is as necessary as food and water for the well-being of an individual. The average healthy adult is accustomed to a single, prolonged sleep of approximate eight hours. During a typical 24-hour day, there are two normal periods of sleepiness: between the hours of 3-5 a.m. and 3-5 p.m. Sleeping less than eight hours per day can result in sleep loss, which can become cumulative.

After sleep loss, the most notable feature of recovery sleep is its increased depth, rather than its duration. This means the following sleep loss, you do not have to sleep the same number of hours that you lost. Sleep loss can be caused by circadian rhythm disruptions, sleep disorders, stress, alcohol and drug use or abuse, excessive caffeine consumption, bad sleep habits, uncomfortable sleeping environments, use of sleeping pills, etc.. In addition, with increased age, sleep becomes less deep and more disrupted, and nocturnal sleep decreases. The main physiological effect of sleep loss is an increase in sleepiness, which causes fatigue.

Circadian rhythm defines a biological cycle of approximately 25 hours that determines the physiological behavior of all body functions. They are influenced by the succession of day and night, changes in ambient illumination, and timing of food consumption, physical activity, and social activities. Circadian rhythms can be affected by a sudden change in individual work-a rest schedules (shift work), sudden relocation to a different time zone, use of medications to sleep and stay awake, alcohol and drug use or abuse, etc.

Various factors affect your ability to adapt to new circadian rhythms:

- Adaption takes longer with increasing age.

-Different body functions adapt at different rates.

-Extroverted people adapt faster than introverts do.

-The greater the time difference between the time of origin and the local time, the longer it takes to adapt.

- Adaption into a backward schedule (longer daytime-west-bound flights) is faster than it compared to a forward schedule (shorter daytime-eastbound flights).

Manifestations of circadian desynchronization,or incomplete adaptation to a new circadian rhythm, include difficulty falling asleep, difficulty remaining asleep, daytime sleepiness, decrease physical and mental performance, gastrointestinal problems, and other signs and symptoms associated with fatigue.

Here's what you can do to prevent fatigue:

- Try to get as much sleep per 24 hours during a trip, as you would at home.

- Use physical or mental relaxation techniques to fall asleep. Sometimes it is as simple as a hot shower or bath before going to bed.

- Do not eat a heavy meal or drink large amounts of liquids before going to bed.

- Eat a balanced diet to prevent in-flight hypoglycemia.

- Do not consume any alcohol or caffeine for at least 3-4 hours before going to bed.

- If you're having difficulty getting to sleep, get up and try activity that helps you fall asleep. For example you could read, listen to soft music, watch a relaxing television program, take a hot bath etc. Counting sheep only works for a few.

- Avoid using sleeping pills to promote sleep and stimulants to promote wakefullness unless they are prescribed by flight surgeon (not likely). The same advice applies to the use of melatonin.

- Take a nap of no longer than 40 minutes immediately before your scheduled flight, if you didn't get enough sleep the night before. A nap can acutely improve alertness because it decreases the length of continuous wake fullness before a flight. Consider it a re-charge of your batteries.

Common misconceptions about fatigue:

- I know exactly how tired I am.

- I have lost sleep before, and I did just fine.

- I motivated enough to just push through it.

- I am a highly experienced and capable pilot and can still fly aircraft even if I am tired.

- I don't need more than three or four hours of sleep every night.

- If I'm tired, all that I need is a cup of coffee (or two... or three) to feel better.

- There is a quick and easy fix for fatigue.