Safety - Drinking Water Program for Workers During Hot Weather

Provision of adequate drinking water and making sure employees drink enough is extremely important during hot weather. The following is information on this subject.

Drinking water is most important in maintaining workers’ health and performance in the heat. A leading cause of heat illness is dehydration, which reduces the body’s ability to disperse heat through sweating. The water needed to replace lost body fluids varies among individuals, and is affected by temperature, humidity, and type of work. Daily water needs for moderate summer work in temperate regions ranges from 6 to 10 quarts. On hot days, a worker can lose 3 gallons of perspiration. At low humidities, you can sweat heavily and still have dry skin. In extreme heat, you can sweat up to 2 quarts per hour, but this rate can not be tolerated for long!

Drink enough water to maintain body weight. Sharp weight losses indicate inadequate water. Other indications are dark yellow urine, and passing less urine than usual. "Weighing in" each morning is a way to monitor weight. Remind workers often to drink water, even when busy.

Thirst does not measure water needs. Workers drinking water only to satisfy thirst drink about two-thirds of that needed. This can mean a weight loss of 2 to 4 pounds on hot days. Chronic dehydration can develop gradually over several days, without thirst. It can lead to such health problems as kidney stones and urinary infections.

Generally, workers in the heat should drink at least a cup of water each 30 minutes, and greater amounts in extreme conditions, even if they are not thirsty. It is easier to drink smaller amounts of water frequently than larger amounts less often. Drinking several cups of water before work gives you a head start. Experienced, “heat-adjusted” supervisors and workers who have not previously followed a strict "by the clock" water-drinking schedule may be surprised at the reduction of heat strain.

Workers should not deliberately limit the water they drink to keep from stopping to urinate. In hot conditions, drinking lots of water does not cause an increase in urine, unless you’ve consumed excessive caffeine.

Generally, 2-3 gallons per worker per hot day is enough. Water temperature should be 50 to 60 degrees F. Most people tend not to drink warm or very cold water in quantity as willingly as cool water.

Soft drinks are not recommended as beverages to replace body fluid. The gas makes them hard to drink in quantity. Dilute ice tea or lemonade are alternatives if sugar content is low. Unfortunately, drinks that “cut” thirst discourage sufficient fluid replacement.

Balanced diets usually contain enough salt, even in hot weather. Heavy salt diets may interfere with heat adjustment, causing illness.

Alcohol increases the risk of heat illness and injuries. Urge workers not to drink alcohol during hot weather before work, and until the end of the evening meal after work, to give their body a chance to replace fluids. Employees who are under the influence of alcohol on the job compromise the employer's interests, endanger their health and safety and the health and safety of others, and can cause a loss of efficiency, productivity, or a disruptive working environment.

Information from "A GUIDE TO AGRICULTURAL HEAT STRESS" from the AGRICULTURAL PERSONNEL MANAGEMENT PROGRAM NEWSLETTER, University of California Cooperative Extension, Fresno, Kings, Madera, and Tulare Counties.