How Wet Bulb Globe Temperature Data Keeps Players Safe

Cool fall nights and football games are the epitome of American high schools and colleges. But the training can actually start months before the games do. Football camps and practices go all summer long for most schools. The hottest months of the year may not be the ideal time to don all that gear, but practicing is necessary for teams to be ready to play in the fall. And as player safety awareness grows, assessing the wet bulb globe temperature is becoming more critical.

Regardless of the sport, protecting players is the most crucial thing for everyone involved. With wet bulb globe temperature data from DTN, you can help ensure that you are doing everything possible to keep participants safe.

Coaches can receive alerts and review changing conditions from their mobile devices. Updated information helps them know if they need to add more breaks or cooling strategies to keep athletes safe. Connect with one of our experts to learn more.

Football players lined up

Players At Risk

Contact sports require players to wear protective gear. But wearing these items makes people more susceptible to heat-related illnesses. The protective pads and equipment trap heat, much like a winter coat does. They also slow the evaporation of sweat, the body’s primary method of cooling.

Coaches and trainers must monitor conditions and make training-related decisions with player safety in mind. Competitive athletes naturally push themselves physically, powering through muscle fatigue and discomfort. But if they push too hard in the wrong circumstances, they can end up in serious medical danger.

Officials and coaches need to learn to recognize the signs of heat exhaustion. They should also be familiar with the weather conditions that can bring on heat-related illnesses. High temperatures are obvious culprits, but humidity also plays a significant role.


What Is Wet Bulb Globe Temperature?

Wet Bulb Globe Temperature (WBGT) is a measure of heat stress in direct sunlight. This reading helps guide decisions related to the amount of strenuous outdoor activity that athletes can safely perform in given conditions.

Heat stress calculations include:

  • Ambient Temperature – This measurement assesses the air temperature in the immediate area.
  • Humidity – Humidity measures the amount of water vapor in the air. High humidity slows the evaporation of perspiration, decreasing its effectiveness in cooling down a body.
  • Wind Speed – Higher winds pull more heat away from the body and make sweating more effective.
  • Sun Angle – The sun’s position impacts the temperature for those on the field.
  • Cloud Cover – The sun emits solar radiation, electromagnetic energy that impacts temperature. Cloudy days affect the level of heat players experience outdoors.

Free local forecasts typically refer to the heat index. This number gives a “feels like” reading based on the temperature and humidity in the shade.

The heat index does not offer enough accuracy for those who have to work or play in direct sunlight. Wet bulb globe temperature monitoring is a more accurate measure of potentially dangerous conditions.

The wet bulb globe thermometer is a handheld device that takes three different measurements:

  1. Dry Bulb Temperature – This part of the thermometer measures the ambient air temperature but does not account for humidity.
  2. Wet Bulb Temperature – A cotton sleeve soaked in distilled water goes over the wet bulb. This section of the device simulates evaporation and measures humidity. Since high humidity limits the body’s ability to cool down, this reading is crucial for safety purposes.
  3. Black Globe Temperature – To get this number, the user inserts a dry bulb into a black covering. This indicates the temperature for someone wearing dark clothing, such as a football uniform, or working out on dark asphalt.

The mathematical formula for WBGT looks like this:
WBGT= .7(wet bulb temperature) + .2(black globe temperature) + .1(dry bulb temperature)

Football player tired on the bench with water bottle

What Is Heat Stroke?

Every year, healthy athletes die due to heat stroke. In fact, exertional heat stroke is the third leading cause of death among high school athletes.

Exertional heat stroke is a severe heat-related illness that occurs when the body significantly overheats. Heat stroke symptoms include an elevated body temperature of 104° F or greater along with disorientation. Other possible signs include a flushed face, dizziness, and headache.

Heat exhaustion typically comes first and involves a less severe increase in body temperature. Heat exhaustion symptoms include a fast pulse, cold and clammy skin, muscle cramps, nausea, or weakness.

Heat stroke can damage the brain, kidneys, or other organs and cause permanent disability or death. Fortunately, heat stroke is preventable with the right precautions, such as using wet bulb globe temperature readings.


How To Use Wet Bulb Globe Temperature Readings

The WBGT device delivers a number based on the formula. This number translates into a set of appropriate precautions. In general, those working with athletes should consider the following guidelines:

  • A WBGT below 80 does not call for restrictions. Healthy, conditioned athletes are unlikely to experience heat stress with proper hydration breaks each hour. New athletes may require more breaks. All athletes should have the approval of their physician before participating in any sport.
  • If the WBGT is 80-85, athletes should have a five-minute break every 25 minutes. In this range, the body will begin to experience heat stress after 45 minutes in direct sunlight.
  • A WBGT of 85-88 warrants a five-minute rest in each 20-minute period. New or unconditioned players should not work out in this range. The staff should provide an immersion pool on site for safety.
  • WBGT readings of 88-90 call for breaks every 15 minutes. Players should not wear pads, and an immersion pool must be on site.
  • When the WBGT hits 90 or higher, there should be no outdoor practices or competitions.

To help boost player safety, make sure they drink plenty of water even if they don’t feel thirsty. Allow players to wear lighter clothes and gear on high WBGT days. Everyone should also wear sunscreen. A sunburn makes it difficult for the body to release heat.


Who Else Uses WBGT Information?

WBGT data is useful for protecting athletes on a field, from high school to professionals. WBGT is also helpful in a variety of other settings, including the construction industry, road crews, and airport employees.

The U.S. Military uses WBGT to manage the safety of recruits in basic training. In fact, it was the military who developed the device.

The Occupational Safety and Health Administration (OSHA) applies WBGT requirements to manual labor jobs. And countries outside the U.S. use WBGT for numerous outdoor activities.

High school football player drinking from water bottle

Your Players Rely On You

Your athletes know how to play hard. They rely on you to help them play safe. Contact DTN today for more information about Wet Bulb Globe Temperature alerts and heat safety planning.