As the summer wears on, the dangers posed by heat stress continue to mount for those exposed to extreme heat or working in hot environments. But what exactly *is* heat stress? What kinds of risks does it bring? And what can you to keep your team safe?
What Is Heat Stress?
The human body maintains a natural temperature between 96°F and 99°F. When your body temperature rises, your body cools itself off by sweating.
However, there are times when your body heats up faster than it can cool itself down, especially in a work environment with high heat and/or humidity. When this happens, you may experience heat exhaustion, heat cramps, or even heat stroke!
Risk Factors for Heat Stress
There are a number of determinants that can increase the risk of heat stress. These include:
High Temperature
A worksite that’s gets a lot of radiant heat from the sun (or the proximity of hot equipment) can pose a danger. This threat is escalated by the presence of high humidity and/or a lack of air flow, which make it even more difficult for workers to cool down.
Heavy Physical Labor
The more active workers are, the more heat they produce. If their bodies are already working overtime to cool off, throwing in some hard work on top of it could be enough to put them in danger.
Poor Health
Factors like advanced age, obesity, and preexisting medical conditions may cause the body to react poorly to overheating.
Poor Hydration
In order to cool itself, your body needs plenty of fluids. At least one pint of water per hour is recommended.
Improper Work Attire
Clothing that is heavy, tight-fitting, or waterproof may trap in heat and prevent your body from adequately cooling.
Lack of Conditioning
Those who haven’t become conditioned to working in high temperatures are more likely to suffer from heat stress. (See Acclimatization below.)
Illnesses and Conditions from Heat Stress
If heat stress goes unrecognized and untreated, it could lead to one or more of the following ailments:
Heat Stroke
Probably the most serious of heat-stress-related illnesses, heat stroke occurs when your body can no longer control its temperature. Your temperature may rise as high as 106°F within 10-15 minutes as your ability to sweat fails and your body loses its ability to cool down. Other symptoms include confusion, loss of consciousness, and seizures. If left untreated, heat stroke may cause permanent disability or even death!
Heat Exhaustion
Heat exhaustion is your body’s response to losing an excessive amount of water and salt through excessive sweating. Symptoms of heat exhaustion include headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, fever, and decreased urine output.
Heat Cramps
Heat cramps generally occur when you sweat a lot during strenuous activity. The low salt levels in your muscles result in painful cramps, pain, or spasms in the abdomen, arms, or legs. If left untreated, heat cramps can easily lead to heat exhaustion.
Heat Rash
Heat rash is a skin irritation caused by excessive sweating in a hot and humid environment. Symptoms include clusters of red bumps or small blisters on the affected area (usually the neck, upper chest, groin, under the breasts, and/or in the elbow creases).
Heat Syncope
Heat syncope is dizziness or fainting that occurs when you stand for too long or when you stand up too quickly after sitting or lying down. This illness can be exacerbated by dehydration and/or a lack of proper conditioning.
Rhabdomyolysis
Rhabdomyolysis (or rhabdo) is a medical condition associated with heat stress and/or prolonged physical exertion. Basically, your muscle tissue breaks down, ruptures, and dies. When this occurs, electrolytes and large proteins get released into your bloodstream, potentially damaging your heart and kidneys. In some cases, rhabdo may be asymptomatic. In others, you may experience muscle cramps, dark (tea or cola-colored) urine, and/or weakness.
Note: This information is being presented for informative purposes only and should not be used for diagnosing heat stress and its related conditions. If you or your workers are experiencing any of the above symptoms, please seek medical help!
Acclimatization
According to the National Institute for Occupational Safety and Health (NIOSH), repeated and controlled exposure to a hot environment can help you adapt physiologically by increasing the efficiency of your sweating, stabilizing your circulation, increasing your skin blood flow, and developing the ability to work with a lower core temperature and heart rate.
To properly adapt to a hot work environment, NIOSH recommends the following acclimation schedules:
- New workers. No more than 20% exposure on day 1, with an increase of no more than 20% per day going forward.
- Experienced workers. No more than 50% exposure on day 1, with an increase to 60% on day 2, 80% on day 3, and 100% on day 4.
Once they’ve adapted, most workers can maintain their acclimatization even if they’re away from the job for a few days. However, an absence of longer than a week may require them to gradually reacclimate.
Tips for Preventing Heat Stress
The best way to reduce the risk of heat stress is to eliminate the sources of exposure. This can include increasing air flow, using reflective or heat-absorbing shielding, and reducing humidity in the work area.
In addition, you may want to consider the following:
- Limit the amount of time your workers spend in the heat.
- Increase the number of workers per task.
- Provide adequate amounts of cool water near the work area (and encourage your workers to drink regularly). Avoid beverages containing caffeine or alcohol.
- Ensure your workers are properly outfitted in lightweight, light colored, loose-fitting clothing.
- Make sure your workers are properly and safely acclimated to the work environment.
- Encourage your workers to self-monitor themselves (and each other) for signs of heat intolerance.
- Implement a platform that monitors your workers (as well as their environment) and alerts you to potential heat stress issues before they occur.