Researchers announced findings that humid days with temperatures of 34℃ (93.2℉) can stress the heart and put people with cardiovascular disease at risk. As global temperatures hit new records this year and extreme weather – including heat domes that have hit the southeast and southwest – become more common, be sure to check both the temperature and moisture before going out.
The newspaper Nature reports that a team from Pennsylvania State University at State College found that more areas are experiencing extremely hot and humid days and people need to take steps to prepare. With few air-conditioned homes or cooling stations, some areas are ill-prepared for rising temperatures.
The team studied the heart rates and internal body temperatures of 51 healthy subjects as they walked slowly through an enclosed environmental chamber that grew warmer and wetter every five minutes. They found that cardiovascular strain started at 93.2℉ in wet conditions, while in drier conditions, test subjects could sustain 105.8℉ without stressing the heart. Previous research had suggested that people could withstand humid environments of up to 95℉ and dry temperatures of 115℉.
“If all of a sudden you notice that your heart rate is increasing rapidly and gradually, it could mean that your core temperature is going to start to rise,” said Rachel Cottle, one of the researchers. said Nature. “That’s when you need to take precautionary measures.”
The heart increases its rate to move cooler blood to keep organs functioning properly – researchers have found that heart rate increases before core body temperature rises as a preventive measure. Therefore, research shows that lower temperatures are more dangerous than previously thought. Even when resting outside on an extremely hot day, heart rates are up to 64% higher when the humidity reaches 50%, another team of researchers from the University of Roehampton reported.
What can you do to prepare for the hottest weather in history?
Unfortunately, an immediate solution to overheating — air conditioning — is a major contributor to climate change because so many regions still burn coal and oil to fuel them. Setting the air conditioning to a temperature above room temperature can reduce your impact on the climate, but in our perversely ironic situation, this necessary evil remains the most practical option. Stay home or in air-conditioned spaces as much as you can. The Environmental Protection Agency recommend setting air conditioners to 78℉ to minimize emissions and your air conditioning bill.
If you don’t have air conditioning, and 10% of Americans didn’t in 2020, there are steps you can take to stay cool at home. If it’s too hot where you live, find public cooling stations near you using the National Center for Healthy Housing’s guide to cooling centers by state. Communities are also sure to open new chill stations, so check local media for pop-up centers near you for the latest updates.
A new concept to many is “wet bulb temperature”, which describes the body’s ability to cool itself through evaporation – sweating – in humid environments. When there is more humidity in the atmosphere, sweating is a less effective way to cool down. At wet bulb temperature, sweat no longer cools the body. Before heading out, check your weather app for the wet bulb temperature or, if it’s not available, you can enter the current temperature and humidity level at Omni Calculator. Don’t forget to look at the maximum temperature predicted for the day, because that’s when the risk will be greatest.
After the hottest days in recorded history — and most likely the last 125,000 years, it’s time to take action to adapt to our ever hotter and more dangerous climate. We can take steps to reduce emissions and eliminate waste that contributes to global warming, but we must stay healthy to make those changes. Stay safe in those warmer places, often fatal time.