Heat, humidity present significant health risks Published June 17, 2008 By Susan Griggs Keesler News KEESLER AIR FORCE BASE, MISS. -- South Mississippi summers can render the hardiest souls "heat beat." The searing heat, coupled with blazing sunshine and oppressive humidity, can cause serious health risks while working, exercising or playing outside. Heat injuries can range from fainting and cramps to heat exhaustion and heat stroke, which may result in brain damage or death unless treated promptly. Monitoring potential dangers To monitor heat dangers, the 81st Aerospace Medicine Squadron's bioenvironmental engineering flight uses special monitoring equipment to perform wet bulb globe temperature measurements during the summer months to determine work and rest cycles. The device is used to take a reading in direct sunlight in front of Building 0420 north of Sablich Center. On weekends, Blake Fitness Center personnel take the readings. The WBGT index considers dry air temperature, air movement, relative humidity and radiant heating. The WBGT index must be measured when the predicted or actual outside temperature reaches 85 degrees Fahrenheit as a daily high, according to Air Education and Training Command Instruction 48-101, Prevention of Heat Stress Disorders. Keesler specifics are outlined in Supplement 1 to the instruction dated Oct. 23, 2001. At Keesler, bioenvironmental engineering technicians and base fitness personnel monitor heat conditions with official readings 8 a.m. to 5 p.m. June 1 through Sept. 30. Times and dates may be extended based on weather conditions. Shifting weather conditions WBGT readings can change significantly during the day if the weather changes quickly. Readings can go from 80 degrees to 75 degrees within minutes if wind increases and clouds move in. That information is given to the command post, which disseminates it to unit control centers across the base. Supervisors determine the type of work their staff is performing and implement the appropriate work-and-rest cycles based on the Occupational Safety and Health Administration's technical manual for heat stress that's produced by the American Conference of Governmental Industrial Hygienists. Flags are posted outside the base fitness centers and the south side of the Levitow Training Support Facility to signal the degree of heat intensity. Colors, WBGT readings, hazard explanations and work-rest requirements are: White flag (78 to 81.9) -- Normal activity for people accustomed to climate; extremely intense physical exertion may cause heat stroke for people who aren't. No limits light and moderate work; heavy work 40 minutes, rest 20 minutes. Green flag (82 to 84.9) -- Normal activity for those accustomed to the climate; people who aren't should use discretion in planning intense physical activity. No limit light work; moderate work 50 minutes, rest 10; heavy work 30 minutes, rest 30. Yellow flag (85 to 87.9) -- People accustomed to the climate should use caution in planning intense physical activity; those who aren't should curtail strenuous activities. No limit light work; moderate work 40 minutes, rest 20; heavy work 30 minutes, rest 30. Red flag (88 to 89.9) -- Those accustomed to the climate should curtail strenuous exercise and limit conditioning for periods not exceeding six hours; people who aren't should terminate all physical conditioning. No limit light work; moderate work 30 minutes, rest 30; heavy work 20 minutes, rest 50. Black flag (90 and above) -- Light work 50 minutes, rest 10; moderate work 20 minutes, rest 40; heavy work 10 minutes, rest 50. Clothing types may add to the WBGT factor. Cloth coveralls add 3.5 degrees Fahrenheit, body armor adds 5 and mission-oriented protective posture gear adds 10 for light work and 20 for moderate and heavy work. The most important safety measure during hot weather is to drink plenty of water or sports drinks a few hours before and during heavy work or exercise. However, hourly fluid intake shouldn't exceed 1 1/2 quarts, and daily fluid intake shouldn't exceed 12 quarts. Rapid ingestion of large amounts of water may lead to hyponatremia, or acute water intoxication, a life-threatening condition that may lead to weakness, convulsions, loss of consciousness and death if not recognized and treated promptly. Also, eat balanced meals, avoid products with caffeine and ensure appropriate work and rest cycles are observed. If a person is unsteady, weak or has muscle cramps that don't go away with rest and fluids, he should seek medical attention immediately. If you notice someone who is confused, unresponsive or vomiting, get them into the shade, remove any excess clothing and call for medical assistance. Try to help him cool off by fanning him or dabbing his face and neck with a cool cloth, but don't throw or pour cold water on him. For current heat conditions, check the Keesler restricted web page or call the command post at 377-4330.