It’s well-known that water, rest and shade help protect workers from heat-related illnesses like heat exhaustion and heat stroke. What you might not know is that these hot weather safeguards can also reduce the risk of a worker suffering a heart attack or other cardiovascular emergency.
How Does Heat Affect the Heart?
Hot, humid weather can be very hard on the heart, and it doesn’t have to be hot for very long for the risk of fatal heart problems to increase. According to the American Heart Association, a heat wave of just two days can increase the likelihood of premature heart-related death. Researchers studying heart-related deaths and daily temperatures in Australia found that hot, steamy weather causes changes in blood pressure, blood thickness, cholesterol and heart rate – all of which strain the cardiovascular system.
A Deadly Hazard
According to the Centers for Disease Control and Prevention, heat-related illness kills more than 600 people every year in the U.S. alone and sickens thousands more. However, since heat stroke and other heat-related illnesses do not get reported to public health agencies – and because heat may not be listed as a contributing cause when a person dies of a heart attack on a hot weather day – the number of deaths related to heat may actually be much higher.
“Exposure to high temperatures at outdoor construction sites can be hazardous to workers’ health,” says LIUNA General Secretary-Treasurer and LHSFNA Labor Co-Chairman Armand E. Sabitoni. “In addition to reducing risk for heat stress and heat stroke, ensuring workers have access to water, rest and shade helps protect their overall cardiovascular health.”
Workers with existing heart conditions are particularly at risk during high heat conditions, but these conditions can also be dangerous for workers who are overweight, over the age of 50 or taking certain medications.
How the Body Keeps Cool
The human body functions best at an internal temperature that – depending on gender, recent activity, food and fluid consumption and time of day – can range from 97.8°F (36.5°C) to 99°F (37.25°C). Maintaining this core temperature during heat-producing activities like pouring asphalt or wearing personal protective equipment requires the body to find ways to get rid of excess heat. It does this through radiation and evaporation (circulation and sweat), both of which stress the heart:
- Radiation: When the body heats up, the excess heat is transferred to our blood and the heart circulates more blood to the skin where it can be cooled. While this can be effective when the environmental air temperature is cooler than body temperature, it’s less effective when air temperature is closer to body temperature. Radiation strains the heart because the heart has to beat faster and pump harder than it normally does.
- Evaporation: When radiation is ineffective, the only way the body can cool itself is through the evaporation of sweat. On a hot day when humidity is low, the evaporation of a teaspoon of sweat can cool the body by as much as two degrees. Like radiation, sweat becomes less effective when humidity is high. Sweating also causes the body to lose sodium, potassium and other minerals the heart needs to function, which can increase risk for heart attack.
When Is it Too Hot for the Heart?
It’s not possible to list an example temperature, as some people are more sensitive to heat than others. However, employers should always check the temperature and the heat index, which takes humidity into account, and make sure workers know the signs of heat illness, the symptoms of a heart attack and what to do when:
- Hot temperatures start rising
- Humidity increases
- There is no air movement
- Protective clothing or gear is worn
- Work is strenuous
The LHSFNA’s Preventing Heat-Related Illnesses in Construction pamphlet and Heat Stress Prevention and Your Heart at Work toolbox talks can help LIUNA signatory employers reduce the risk of heat-related illnesses and heart attacks on site. Order through the Fund’s online Publications Catalogue or contact 202-628-5465 for more information.
Stay Cool Indoors
When it’s extremely hot outside, the heat inside can be deadly. If your home doesn’t have air conditioning, find a place that does, even for a few hours. This will help relieve the stress on your heart when you do go back into the heat.
Go to a shopping mall, public library or other facility that has air conditioning or call your local health department for a list of heat-relief shelters. Click here for additional tips for staying safe in the heat.
[Janet Lubman Rathner]