The last place we want to have a breakdown in our descision making process is when we are sitting in the seat with the best view. Yet, there is one simple thing to remember that will help prevent a loss of brain power......water.
Most pilots don’t even think about it. Others simply don’t understand the symptoms and effects. Even on a mildly warm day it can cause a dramatic increase in aircraft incidents and accidents. What can cause this, you ask? Pilot dehydration. The FAA has determined that this phenomenon is such an area of concern that they have included it in the Practical Test Standards list of physiological conditions.
Typically, we associate dehydration with thirst and assume that we can drink any kind of liquid to satisfy that urge. After that sip of soda, iced tea or sports drink we may no longer be thirsty, but in many cases this makes the dehydration problem even greater. The dehydration condition is caused by a lack of water within the body cavity due to high body temperatures, a dry aircraft environment, excess caffeine or inappropriate fluid intake. A hot cockpit and flight line can cause an increase in fluid loss. With the extreme heat here in Arizona and the aircraft interior having low relative humidity, there can be a dramatic effect on your body’s hydration. Many soft drinks contain high amounts of caffeine and sugar and can prevent proper absorption of the water content.
Your body’s ability to regulate heat is effected with even a small amount of fluid loss. (As little as 2% of your total body weight). Fluid loss of as little as 4% of your total body weight can cause a reduction in muscle contraction times and can have noticeable effects on your overall performance both mentally and physically.
According to a recent Federal Air Surgeon Bulletin, there are three specific stages to dehydration: Heat Stress, Heat Exhaustion and Heat Stroke. The changes between each stage are not that obvious, so you must monitor your conditions closely when in hot/dry weather. Most people will become thirsty with a 1.5-quart deficit, or a loss of 2% of total body weight. This level of dehydration triggers the "thirst mechanism." The problem, though, is that the thirst mechanism arrives too late and is turned off too easily. A small amount of fluid in the mouth will turn this mechanism off and the replacement of needed body fluid is delayed.
Dehydration symptoms go beyond thirst. Frequent visits to the restroom can be a sign of the kidneys responding to the brain’s need for fluid. The kidneys reabsorb water through the urine and create greater fluid retention. Headaches, fatigue and lightheadedness are also signs of dehydration. Dry skin is also an indicator as most of the moisture in our skin comes from inside our bodies. Poor decision making and unclear thinking are also signs that may you may be experiencing some level of dehydration. Some long-term effects can be impaired memory, brittle nails and sinus infections.
So, to avoid dehydration in the cockpit, you need to have water available and drink it regularly. You should drink two to four quarts of water every 24 hours. Since each person is physiologically different, this is only a guide. Most people are aware of the eight-glasses-a-day guide. If each glass of water is eight ounces, then you end up with 64 ounces, which is two quarts.
The Federal Air Surgeon Bulletin also suggests drinking cool, 40-degree water before feeling thirsty and getting into the cockpit. Some of the sports drinks readily available for fluid replenishment should be used judiciously. Although these drinks are designed to replace the fluids and electrolytes that are lost during exercise and stress related activities, because of their sugar content they may lower your systematic blood sugar level and cause an abrupt onset of fatigue.
The FAA also suggests staying away from diuretic drinks such as coffee, tea and soda. These drinks have high levels of caffeine and carbonation that may cause excess urine production and/or decreased voluntary fluid intake.
Also, keep in mind that it may take up to two weeks for your body to become used to changes in climate.
Some experts also suggest moving your leg muscles or shifting in your seat more often while flying. Dehydration causes a reduction in blood flow and doing these simple tasks will help to move the blood throughout your body.
Listed below are the three stages of dehydration/heat exhaustion. Remember that the transition from one level to the next may not be evident.
· Performance, dexterity, and coordination
· Ability to make quick decisions
· Alertness
· Visual capabilities
· Caution and caring
2. Heat exhaustion (101-5° F) symptoms:
· Fatigue
· Nausea/vomiting
· Giddiness
· Cramps
· Rapid breathing
· Fainting
3. Heat stroke (>105° F) symptoms:
· Body's heat control mechanism stops working
· Mental confusion
· Disorientation
· Bizarre behavior
· Coma
Here are some suggestions on how to become more aware of and help prevent dehydration/heat exhaustion.
- Drink cool (40° F) water.
- Carry a container so you can measure daily water intake.
- Don't rely on the thirst sensation as alarms...stay ahead. If plain water is offensive, add some sport drink flavoring to make it more acceptable.
- Limit your daily intake of caffeine and alcohol.
- Exercise can cause a large amount of body fluid loss that is difficult to replace quickly. (Don’t exercise heavily before a flight).
- Acclimation to a major change in weather takes one to two weeks.
- Monitor personal effects of aging, recent illness, fever, diarrhea, or vomiting.
- Monitor your work and recreational activity; if you feel light-headed or dizzy, call it a day.
- In extreme heat and exercise conditions, salt and electrolyte loss is a factor but not for the average person with a moderate exercise program.
The most important factor is prevention. Dedicate yourself to becoming acutely aware of your own physiological and environmental conditions. This awareness will help you maintain a healthy water intake and prevent you from becoming a victim of dehydration or heat stroke by simply taking a few good gulps of water.
Great information,
ReplyDeleteThank you