The Science Of Hydration: Keeping Cool When the Temperature is Hot
Water is essential to life. It regulates the body’s internal temperature, acts as a building block for cells and helps flush waste. Without water, the consequences can be more than just a dry mouth. Dehydration can mean dizziness, weakness, fainting, muscle cramps, rapid heartbeat and possible death.
While a lack of proper hydration can spell disaster for anyone, for contractors it can be particularly dangerous. Working outdoors in the heat and direct sunlight or indoors in poorly ventilated areas, coupled with not drinking enough water, can produce life-threatening results.
The way to be safe is simple: drink water. The other thing to do if you think you’re experiencing dehydration or suspect a coworker may be having symptoms is to get to a doctor or clinic as quickly as possible.
The average adult human body is about 60 percent water, so maintaining a proper fluid balance is essential for all bodily functions. The body also works to maintain a constant 98.6-degree temperature by sweating. Dehydration makes it harder for the body to thermoregulate – that is, to maintain its internal core temperature.
Dehydration can come on suddenly with few warning signs. Perhaps the first thing most people notice as a result of dehydration is the lack of sweat. Sweating is the body’s air conditioner, releasing heat as it evaporates from the skin. Dehydration means there is not enough water to produce sweat. Body heat stays trapped and core temperatures can rise, leading to heat exhaustion or even heat stroke.
At the same time, urine output decreases as the body attempts to hang on to enough fluids to provide adequate blood flow to the heart, muscles and brain. Blood volume also begins to decrease – but the heart still has to pump the same amount through the body to provide cooling and deliver nutrients to the muscles. The reduced volume makes the heart work harder, creating an even greater risk for heat exhaustion.
As blood vessels begin to constrict due to a lack of water, dehydration headaches can start. From there, thinking becomes fuzzy and ordinary tasks become harder to do. It becomes easy to make sloppy mistakes that can cause injuries.
For contractors who are working in unfavorable conditions (high temperatures, blazing sun and a lack of proper ventilation), heat stress and dehydration are real concerns. Compounding the problem is the heat put off by large equipment or the lack of ventilation that comes from working indoors. Protective gear can add another 10 to 15 degrees to any day. Contractors can sweat out more than a quart and a half of water per hour and begin to feel the effects of dehydration after just two hours of moderate work.
How To Stay Hydrated
The most obvious way to avoid dehydration is to drink water, but determining how much is the big question.
For people with physically demanding jobs, including anyone working as a contractor, the Occupational Safety and Health Administration (OSHA) recommends drinking about 7 ounces of water every 15 to 20 minutes. The American Heart Association suggests drinking 16 ounces of water for every pound of sweat you lose. The Institute of Medicine recommends about a gallon of total daily fluid intake for the average adult male.
The amount of water intake also depends on the level of physical activity and medical conditions such as diabetes or heart disease.
Better advice is that contractors, like athletes, should drink fluids before they start feeling thirsty – especially since physical activity can dull the ability to determine when fluids are needed. Drinking plenty of water before, during and after a project can help keep workers from ending up in the emergency room for intravenous fluids.
Also, remember that dehydration is not just a hot-weather issue. Dehydration also can exacerbate hypothermia, frostbite and a range of other conditions that can put a crew in danger.
More Than Just Water
The best way to stay hydrated is to drink water. It's calorie-free, caffeine-free, inexpensive and readily available. Crushed ice also is a good source, as are some teas, juices, sodas and sports drinks. While caffeinated drinks can count as good liquid sources, they can trigger headaches and insomnia. Some foods also count toward liquid totals. Good choices include soups, yogurt, watermelon, salads and oranges.
Dehydration Warning Signs
Crewmembers should learn the signs of dehydration and be instructed on how to monitor themselves and fellow workers. Indicators of heat-related illnesses include:
- Urine output – Dark yellow urine is probably the easiest way to detect dehydration. If the urine is dark brown or reddish in color, get to a doctor quickly.
- Heat rash – Blistered rashes in sweaty areas, like the neck, chest, underarms and elbows, can indicate potential dehydration-related problems. Move to a cooler area and apply powder to the rash.
- Heat cramps – Abdominal muscle and leg cramps that appear suddenly are also an early indicator of dehydration. Treatment includes drinking water or sports drinks and moving to a cooler area.
The most dangerous dehydration and heat illnesses include:
- Heat exhaustion – When the body temperature spikes above 100.4 degrees, symptoms include increased thirst, heavy sweating, nausea and confusion.
- Heat stroke – When the sweating stops and the body can’t regulate its temperature, internal functions begin to shut down. Heat stroke is the most serious form of dehydration- and heat-related illness and can cause death.
Always seek medical attention – or call 911 for a fellow worker – if you notice any of these symptoms.
Remember, the best way to avoid any medical problems is to drink water before, during and after spending any time on the job.