Beating the Heat: How to Fight a True Public Health Problem

Extreme heat doesn't get the attention it deserves—and although the riskiest part of the year might seem over, it isn't


During a cold spell last winter, as I zipped up to go outside on a truly frigid day, I started to worry: Summer was around the corner, and it was time to get working on a plan for the heat.

Now six months later, summer may be coming to an official close according to school calendars, but not for public-health officials. "Extreme heat events"—otherwise known as those brutally hot and humid days in the summer—kill somewhere between 180 and 1,800 Americans every year. My colleagues in southwestern states and even in the mid-Atlantic are still on the alert for more high temperatures and public risk in the coming weeks.

Heat causes dehydration, increases the work of the heart, stresses our cooling mechanisms (such as sweat), and challenges us to find a cool shelter. Those who are fragile medically or socially risk falling into a downward cycle of more dehydration and stress ... leading to heat exhaustion, heat stroke, and death. Heat can cause death directly and indirectly, by increasing mortality associated with a number of chronic conditions. And the consequences can be dramatic. In August 2003, a heat wave caused as many as 15,000 deaths in France alone.

Every summer, seasonal threats such as West Nile Virus generate news. There's enormous attention to the daily weather report. But there is relatively little focus on heat itself as a public health problem—in other words, as a challenge to be taken apart with numbers and then attacked with a coherent, prevention-oriented strategy.

In June 2006, when I was the health commissioner in Baltimore, I came across the Excessive Heat Events Guidebook from the Environmental Protection Agency.

The Guidebook is a terrific report. It provides data, case studies, and recommendations for saving lives when the going gets hot. It tells the story of Chicago, when the coroner reported that 465 people had died from the heat between July 11 and July 27, 1995. Two of the key risk factors for death in Chicago were social isolation and lack of air conditioning. People who have trouble leaving home—whether for economic, psychological, or physical reasons—are at special high risk during heat emergencies.

The Guidebook recommends that localities develop programs designed to prevent heat-related illness, by predicting events, notifying the public, and providing support for those at highest risk. It cites early programs in Philadelphia and Toronto as benchmarks for future efforts.

In Maryland, under Governor Martin O'Malley, we consider heat emergencies among the "all hazards" that pose a threat to our state's residents. Others include snowstorms, hurricanes, intentional attacks, and contagious disease. Starting on that cold day in winter and working into the spring, the Health Department reviewed the data from our own state and elsewhere about those at risk during heat emergencies and then worked with other state agencies and localities to put together a heat emergency plan.

Under the plan, our emergency preparedness team at the Health Department tracks the weather daily and alerts localities to dangerous conditions. We also monitor reports of ambulance transports for heat related illness and coroner reports of heat-related death (25 as of August 9, compared to 32 for the summer of 2010).

Local health departments and emergency managers then use this information to protect the public. They issue "heat alerts," open cooling centers, coordinate transport for nursing home residents when the air conditioning breaks down, check in on the vulnerable, respond to field trips gone awry, advise camps and senior centers, and provide the public with guidance about major outdoor events.

A wide range of state agencies—from the school system to the social services program to the Department of Transportation—lend a hand to support local response, coordinated by our state emergency management agency. Whenever possible, we reinforce key public health messages, including that people, especially in vulnerable populations, dress for the heat, drink plenty of water, avoid alcohol, take regular breaks, and stay indoors as much as possible. When I'm interviewed on radio or television, I always say: "Please look in on your neighbors—this is when they need you the most."

Once those of us who were involved in executing this year's plan get through the next few weeks, we will meet to figure out what went right and what can be improved for next year. Many of these lessons will help our state respond to other threats as well.

And there are plenty of threats out there. For instance, during one of the hottest days recently—and I mean truly sweltering—I felt a nagging anxiety: Cold weather is not too far off, so we need to get working on our influenza plan.

Image: Brian Snyder/Reuters