Oof.

This is quite the week for hot, muggy, and smoky conditions in the United States. We are seeing all sorts of alerts across the country.

The dew point will reach more than 70 in the next ten days in more than half of the country. In other words, millions will be lucky enough to experience jungle-like conditions. (For reference: dew point <50 is comfy; 60-65 feels sticky; >65 is muggy; >70 is tropical.)

But all of the above isn’t necessarily a surprise. Meteorologists predicted an unusual heat this summer, with a number of areas to experience temperatures above normal.

The reason for this depends on region:

• Northeast: Ocean temperatures higher than normal, which increases air temperatures.
• South: Heat dome from Mexico, one the strongest ever recorded. According to Climate Central— a climate science non-profit— climate change made this extreme heatwave at least five times more likely.
• West: Drier-than-normal thanks to El Niño.

Heat illness

The biggest health concern with high heat indexes (combination of temperature and humidity) is “heat imbalance”—the heat the body produces is more than the heat it looses. The body typically fixes this with sweat, but in extreme heat it’s sometimes not enough. The heat can build up inside causing a wide range of symptoms, including death.

We can already see an uptick in emergency room visits (per 100,000) for heat-related illnesses thanks to CDC’s super cool real-time surveillance tracker. Unfortunately, we’ve already seen a number of deaths. There have been two in Texas reported: a 14-year-old hiker in Big Bend National Park and a postal worker on his route in Dallas.

Anyone can be at risk, but there are particularly high-risk groups:

• People over 65
• Infants and children
• Pregnant people
• People with heart or lung conditions
• Athletes
• Outdoor workers
• Those in urban areas

Heat illness is preventable. We can actively help our bodies with the internal heat balance. The major source of heat buildup is from physical activity. Limit this outside, if possible. Other things that help:

• Hydration. This means water. Not Red Bull. Not Gatorade. Water. Limit alcohol.
• Stay cool in air-conditioned areas.
• Wear lightweight, light-colored, loose-fitting clothes.

Heat illness can creep up fast. The CDC put together a helpful chart of signs and symptoms to look out for, and what to do depending on severity.

Bottom line

It’s a scorcher out there, and it’s not even July. Take the heat seriously, as it’s only increasing heat-related illnesses. They are preventable. Stay cool.

Love, YLE

The YLE archive can be found here. In case you missed it:

• It’s wildfire season. Here’s what to do.
• Wildfire smoke, COVID-19, and striking comparisons

“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist. During the day she is a senior scientific consultant to a number of organizations. At night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health world so that people will be well equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members. To support this effort, subscribe below: