Personal Risk Factors and Heat Exposure 

Overview

Hot work environments can be dangerous for all workers, especially over long periods of time. Millions of 

workers are exposed to heat in their workplaces and thousands of workers are sickened each year from heat 

injuries or illnesses. Even workers who have built up tolerance to, or acclimated to, the heat need to be careful. 

This is because some workers feel the effects of heat differently than others. It’s important to know what may 

make you more vulnerable to heat injury and illness. 

This is a guide that will help you identify which factors may cause you to be more at risk for heat injury and 

illness. In addition to the environment you are working in, the clothes you are wearing, and type of work 

activities you are doing, certain health conditions, medications, and physical and behavioral characteristics may 

increase your risk for heat illness and injury. 

Your work environment and activities may increase your risk of heat injury and illness. In addition, you may also 

have one or more personal risk factors that increase your risk. 

Although you may be exposed to similar levels of heat and engaged in the same type of work as your coworkers, 

personal risk factors may cause you to be at greater risk for heat injury and illness. Ultimately, it is the employer’s 

responsibility to ensure that the workplace is safe and healthful for workers; however, a heat injury and illness 

prevention plan needs the meaningful participation of workers and their representatives to be effective.

Personal Risk Factors

Health conditions

Behavioral

characteristics

Physical

characteristics Health conditions Medications Phys Behavioral Me ical dications

Heat Injury and

Illness Risk Factors

Work Activities

The type of work you are doing can make

you more susceptible to heat. These 

factors may cause your body temperature 

to increase:

• Level of physical activity and exertion

• Clothing or protective gear that can 

reduce your body's ability to cool itself

• Inadequate rest breaks

• Inadequate acclimatization scheduling

Work Environment

A combination of environmental factors 

increase your risk of heat injury and illness. 

These include:

• High temperature

• High humidity

• Heat from hot sources (radiant heat),

such as hot tar ovens and furnaces

• Limited movement of cooler air

• Frequent direct sun exposure
Personal Risk Factors

Use the following diagram to learn more about which factors may reduce your tolerance to heat. 

Health conditions

Some health conditions may cause you to be less likely to sense and respond 

to changes in temperature.

• Diabetes

• High blood pressure

• Heart disease

• Kidney disease

• Mental health conditions

• Overweight or obese

• Respiratory diseases, like asthma and chronic 

obstructive pulmonary disease (COPD)

Medications

Certain medications may cause you to be less likely to feel heat conditions 

and/or limit your ability to sweat or retain water to cool your body.

• Antihistamines

• Blood pressure medications

• Diarrhea medications

• Diuretics (water pills)

• Muscle relaxants

• Psychiatric medications

• Sedatives

Physical characteristics 

Some physical characteristics may cause you to become dehydrated faster 

and/or limit your ability to cool your body.

• Older age (60 years and older)

• Lower level of physical fitness

• Pregnancy

• History of prior heat illness

• Acclimatization status (i.e., if you have built up 

tolerance to the temperature you are working in)

Behavioral characteristics

Certain decisions, like what you consume and put in your body, may dehydrate 

you and impair the way your body normally regulates itself.

• Alcohol use within 24 hours 

of your shift

• Use of illicit drugs, such as opioids, 

methamphetamine, and cocaine

• Lower intake of water

Note: this list is not comprehensive. Other factors can also make you more susceptible to heat injury and 

illness. Talk to your doctor to see if any of your health conditions, medications, or other aspects of your life 

increase your risk of suffering a heat illness, and find out what methods you can take to reduce that risk. 
Staying Safe

Heat injury and illness can be prevented, and you can prepare for working in hot environments. 

Use the tips below to help plan how you can stay safe at work:

Talk to your medical 

provider. 

Discuss how you can best prepare 

for work in hot conditions.

Stay hydrated. 

Drink 1 cup (8 oz.) of water every 

15‐20 minutes, even if you are not 

thirsty.

Take rest breaks. 

It’s best to rest in air‐conditioned 

or cool, shaded areas.

Wear clothing that is safe 

yet minimizes heat stress, 

if possible.

Loose fitting and light‐colored 

clothing made of breathable 

fabric, like cotton, allow your 

body to cool more easily.

Remember your 

acclimatization status. 

When returning to work after time 

away or if conditions get hotter, 

gradually increase back to your 

normal workload. 

Know the signs and 

symptoms of heat illness. 

If you feel ill, notify your supervisor 

and move to a cool space.

Be a buddy. 

Check on your coworkers, and if 

they show any signs of heat illness, 

report it to a supervisor. Cool them 

right away with water or ice, and 

stay with them until help arrives.

Know what to do in an 

emergency. 

Ensure you know your workplace’s 

emergency response protocols. 

When in doubt, call 911!
Additional Information

For more information on preventing heat injury and illness, check out the following resources:

Building Heat Tolerance and Protecting New Workers

Signs and Symptoms of Heat‐Related Illnesses and First Aid

Water, Rest, Shade

Sources 

OSHA: www.osha.gov/heat‐exposure/

NIOSH: “Heat Stress Risk Factors” www.cdc.gov/niosh/mining/UserFiles/works/pdfs/2017‐125.pdf

NIOSH: www.cdc.gov/niosh/topics/heatstress/recommendations.html

Federal law entitles workers to a safe workplace. Workers have the right to speak up about hazards without fear 

of retaliation. See www.osha.gov/workers for information about how to file a confidential complaint with OSHA 

and ask for an inspection. 

1-800-321-OSHA (6742) | TTY 1-877-889-5627 | www.osha.gov/heat