Hydrating in the Heat

Drinking water and staying hydrated is a simple task that can make a huge difference.

• By Alex Saurman
• Jun 01, 2023

With summer and warm temperatures just around the corner, many employees will soon—if they haven’t already—find themselves working in the heat. When the sun comes out, everyone needs to take extra precautions to ensure heat-related injuries, illnesses and fatalities are avoided.

One component of staying safe in the heat is something many people do daily but might not think about: staying hydrated.

The importance of hydration cannot be overstated. Per the University of Nebraska-Lincoln, high temperatures and physical exertion can lead to a greater chance of dehydration. Why is this a concern? Besides the fact that water keeps our bodies functioning and helps us maintain a healthy body temperature, dehydration can lead to heat injury and illness, seizures, weakness, organ damage and, in severe cases, death.

How Much Water Should Employees Drink?

Hydration shouldn’t start the moment you clock in—it should begin well before. According to the National Institute for Occupational Safety and Health (NIOSH), not only do workers want to ensure that they’re hydrated prior to starting work, but they also need to drink water before the feeling of thirst sets in. When this happens, the body may already be dehydrated.

The amount of water people should drink on a daily basis differs for everyone. Activity level, health concerns, medication and temperature all play a role in how much a person should consume. However, when it comes to staying hydrated while working in the heat, the answer is a little clearer.

Every 15 to 20 minutes, employees in hot temperatures should drink eight ounces of water, according to NIOSH. Waiting longer between drinking—even if higher quantities are consumed—is not recommended as “drinking at shorter intervals is more effective,” per the agency.

Although water is vital, drinking too much can have negative consequences. When working in high temperatures, NIOSH and OSHA say employees should avoid consuming more than 48 ounces every hour or 48 cups in 24 hours.

When work is done for the day, don’t clock out on staying hydrated. During a shift, especially in extreme temperatures, employees can sweat, causing water and salts, or electrolytes, to leave the body. These need to be replenished.

Can You Tell When You’re Hydrated?

Although it’s helpful to know how much water to consume and when to consume it, how can employees tell if they’re sufficiently hydrated or if they need to drink more water? 

Luckily, there’s a simple solution: look at the color of your urine. Although there are many ways to check your hydration status, a trip to the restroom can provide a quick answer that might tell you what your body needs. 

Let’s take a look at what the color of your urine means in terms of hydration, according to the New South Wales Ministry of Health (NSW Health) and New Mexico Tech (NMT).

Pale or light yellow. Urine that is pale or light yellow indicates that you’re well hydrated. However, continue to drink water regularly to maintain this level of hydration. If you notice completely clear urine, you may be overhydrated, per the United States Anti-Doping Agency.

Slightly darker yellow. When urine output is a little darker than a pale or light yellow, per NSW Health, you’re “mildly hydrated,” so drinking eight ounces of water once you learn this is suggested.

“Amber or honey” yellow. Starting to notice that your urine is getting darker? That might be a sign to drink up. According to the NMT, if your urine resembles the color of “amber or honey,” you should consume about 16 ounces “if you’re outside and/or sweating.”

Very dark yellow. If your urine is extremely dark or is similar to the color of—as stated by NMT—“syrup or brown ale,” you may be seriously dehydrated. In this case, you need to consume water right away. Some sources, like NSW Health, recommend “a large bottle of water,” but others do not specify an exact amount.

Employers, to encourage employees to check their urine color, consider hanging a urine color chart in rest areas or individual bathroom stalls.

Can Other Drinks Besides Water Affect Hydration?

Water is not the only drink most people consume throughout the day. People often choose what drink suits their needs or wants. Some might prefer energy drinks to help get them through a long shift while others may pick soda or a sweeter drink simply because they enjoy the beverage’s flavor.

But when you’re working in hot temperatures, should these or other non-water drinks be avoided, and what effect does consuming them have on hydration?

Caffeinated beverages. According to Harvard University, “Although caffeine has long been thought to have a diuretic effect, potentially leading to dehydration, research does not fully support this.” Though urine output can decrease with too much caffeine, that doesn’t mean it will cause dehydration. In fact, NIOSH says that “The amount of caffeine in tea, coffee, and soft drinks probably will not have an effect on overall hydration.”⁷

Energy drinks. Some workers turn to energy drinks to help them get through the day, but one of the significant ingredients in these beverages is caffeine, per the National Center for Complementary and Integrative Health.

Alcohol. Consuming alcohol before or during work hours is extremely dangerous. Not only does inebriation lead to changes in coordination, impaired judgment and dizziness—which negatively affects a worker’s ability to do their job safely—but it also brings about dehydration, per NIOSH.

Sports drinks. When people sweat, their bodies can lose salts, or electrolytes. Although NIOSH says water and meals should help keep electrolyte levels even, in cases of extreme sweating, sports drinks can be utilized. But drink too much and your calorie intake will also increase. In addition, the consumption of salt tablets to replenish lost salt is not recommended by NIOSH.

All in all, other options for hydration do exist, but, in NIOSH’s words, “Water will almost always maintain hydration during work in the heat, as long as you eat regular meals to replace salt lost in sweat.”

This article is meant solely for educational purposes and not to provide medical advice. Please seek medical attention or advice from a professional if you are concerned about your health or have questions about hydration.

This article originally appeared in the June 1, 2023 issue of Occupational Health & Safety.