Amid cresting heat waves around the globe, Dr. Katelyn Moretti of the Warren Alpert Medical School relays the risks of high temperatures and how to keep cool and prevent dehydration.
PROVIDENCE, R.I. [Brown University] - As summer temperatures soar, so do cases of heat-related illness.
Waves of sudden or extreme heat can be particularly dangerous, especially for people with certain risk factors, says Dr. Katelyn Moretti, an assistant professor of emergency medicine at Brown University's Warren Alpert Medical School and emergency medicine physician at Miriam and Women and Infants hospitals in Providence.
People are most comfortable when their body temperature is around 98 degrees Fahrenheit, and conditions that raise body temperature above 100 degrees are problematic. Hospitalizations increase when outdoor temperatures climb above 85 degrees with high humidity and drastic temperature swings, Moretti said.
"Those who live in cooler climates may have a harder time dealing with extreme heat than those in the South, who may be used to it," said Moretti, who researches the health implications of climate change and the connections between the health care industry and climate, and is co-founder of the Rhode Island Medical Society Climate Change and Health Committee.
As summer temperatures surge, Moretti discussed how extreme heat affects the human body and how people can best protect themselves.
Q. What does extreme heat do to the human body?
The body responds to heat by dilating blood vessels in the arms and legs and sending blood to the periphery. Heat is then able to leave the body through sweat and transfer to the air and other objects, which creates a cooling effect. However, this means that less blood is flowing to vital organs such as the heart or kidneys. In addition, heavy sweating causes the loss of water as well as salt, which can cause dehydration. This can be dangerous, especially for people taking medications that control their fluid and salt levels. When the natural cooling mechanisms fail to operate properly - whether because of chronic disease, medication or extreme outdoor temperature - then heat exposure can result in kidney failure, heart attacks, brain damage and even death.
Q: What conditions typically send people to the ER during a heat wave?
People certainly come into the hospital because the temperature outside feels too hot for them, but there are also a variety of illnesses associated with heat that can be quite dangerous. During a heat wave, we tend to see exacerbations of heart and kidney problems, chronic obstructive pulmonary disease, asthma and more. We also see a huge increase in mental health issues, including depression, schizophrenia and suicidality.
Q: How does humidity exacerbate heat-related health risks?
Humidity augments the effects of heat. If the humidity is above 75% to 80%, then sweating isn't as effective as a cooling mechanism. When high humidity is coupled with temperatures above the average body temperature of 98 degrees Fahrenheit, then it's even harder to cool down. During the most recent heat wave, which exceeded these heat and humidity thresholds, we saw several individuals, including people who had been working outside, come to the emergency department in a severely overheated state.
Q: What are some factors that increase a person's risk for heat-related illnesses?
Anyone who can't easily get to a cool place is at risk, including homeless people, workers who labor outdoors, and disabled and elderly people. In addition, elderly people are often prescribed medication that predisposes them to dehydration.
Also at risk: People with underlying kidney or heart disease, people with mental health conditions whose standard medications may disrupt the body's ability to regulate heat, and children - their hormonal pathways are still developing, so they become dehydrated much faster than adults and may not recognize they're getting overheated until they're in a dangerous situation.
During heat waves, we see an increase in pregnancy-related complications because the body has to work harder to cool down the pregnant person as well as the developing baby. Research shows pregnancy increases the risk of heat exhaustion, heat stroke and other heat-related illness. There's an association between exposure to severe heat during pregnancy and low birth weights and pre-term births.
Q: How do consistently high temperatures affect health?
Consistently elevated temperatures, including at nighttime, are particularly harmful because the body doesn't have a chance to cool down and recover. This chronic exposure likely has a cumulative, compounding effect on health, especially for vulnerable populations.
