What have you learned about the impact of frigid temperatures on people who live on the street? After four years of medical school and three years of residency, I was struck – in this job – by how little I knew about frostbite, hypothermia and related issues. I was uniquely unprepared to know how to handle the complexities of these medical problems.

Every night in Boston, a van from the Pine Street Inn searches for people at risk for frostbite and hypothermia on the city’s streets. Two nights a week, the van team includes Jim O’Connell , M.D., who helped found the Boston Health Care for the Homeless Program in 1985 and now serves as its president. In this edited Q&A, he addresses the medical risks that extreme cold presents to people living without shelter – and what passersby can do to help.

When I started to learn about the concept of hypothermia, I discovered that Hannibal lost 50 percent of his Army crossing the Alps in 218 B.C. In the War of 1812, Napoleon lost 50,000 troops to hypothermia during their retreat from Moscow. And 10 percent of U.S. casualties during the Korean War were related to the cold. Interestingly, most of the literature about weather-related medical issues comes out of the military and from those crazy mountain climbers. Exposure to the elements is a fundamental part of wilderness literature, but not prominent in everyday medical literature.

What happens to the body during hypothermia?

Only about 33 to 40 percent of hypothermia cases are related to exposure to weather. Most cases involve an infection that causes the body to lower its temperature or a reaction to medication or use of drugs or alcohol.

The worst cases of weather-related hypothermia we see in our program are not during bitterly cold periods but in the shoulder season between fall and winter. The temperature might be in the 40s during the daytime and people on the street feel comfortable. But when the temperature plummets into the 20s at night, those who have fallen asleep outside can unwittingly experience extreme hypothermia, especially if they have been drinking alcohol or using drugs, or if their clothing is wet from rain or the ground.

On a warm day, your body cools down by opening blood flow to skin by sweating. The opposite happens in the cold. The body shuts down blood going to the surface of your skin in order to preserve warmth closer to the heart. This can leave the extremities, particularly the hands and feet, with insufficient blood flow to withstand the cold temperatures.

What is autoamputation?

Each year at our medical respite facility, the Barbara McInnis House, we care for between 10 and 15 people suffering from frostbite that threatens digits and limbs. Hands and feet and tips of noses can swell and develop blisters as if they’d been burned. Bloody blisters indicate deep tissue damage and more severe frostbite. Over the course of two to four weeks, the skin turns black and necrotic.

Because we don’t know how much viable tissue, if any, is below these blackened digits, surgery is not usually done and we are left to watch and wait for one to three months — with considerable horror to our patients and our staff — for the fingers and toes to autoamputate (a spontaneous detachment of an appendage from the body).

Over time, the line between dead tissue and good tissue declares itself and the dead tissue will fall off or autoamputate. The dead tissue will slough off in various ways, often as a tip of finger or toe or a whole digit. If the patient is lucky, the necrotic tissue will be only one or two layers deep. They’ll end up with a finger that may be disfigured but alive and functional.

Often people wake up to find that a finger or a toe has fallen off in bed. Whatever journey has led them to living on the street ends up costing them something they’ll have to live with forever. It’s profoundly unnerving. Frostbite is an emblematic, avoidable and disastrous consequence of exposure to the elements.

What is paradoxical undressing?

As hypothermia progresses, people perceive that their body is becoming warm and they begin taking their clothing off – just when they need it more, they’re taking it off.

As much as we think about dying in the cold as horrible, I remember one man with profound hypothermia telling me that after enduring the initial pain from the bitter cold he had a sense floating on air and feeling warm and euphoric. He said he felt as if his body was floating toward the heavens and that he was bummed when woke up with frostbite. He said hypothermia would have been a nice way to die.

I don’t know if anybody really understands the mechanism at work, but one assumption is that as you get colder and colder, the body tries to preserve blood flow to the heart so it shuts down blood flow to the limbs and to the brain. And the blood that is reaching the brain is more viscous and not flowing freely. A strange mental status results, with confusion and disorientation and a poor perception of temperature that makes the person feel too hot for all the layers of clothing.

We had an extraordinary case several years ago involving a man living under a bridge near Forest Hills in Jamaica Plain. Police and EMS responded to reports of someone dancing naked and acting crazy in the freezing cold. As the temperature dropped, he had become profoundly hypothermic and was apparently feeling warm and euphoric. He died under the bridge later that night.

Dr. Jim O’Connell, with patients (Courtesy Jeff Loughlin)

One of the challenging aspects of recognizing hypothermia on the street is the prevalence of severe and persistent mental illness among rough sleepers. We can easily mistake confusion and disorientation caused by hypothermia with the psychosis of a chronic mental illness. During severe cold spells, Boston police and EMS are alert to this problem and respond with great care and concern. The Mayor and the Boston Public Health Commission have worked diligently for many years to orchestrate a citywide response in an effort to coax people living on the streets into warm shelters on these bitterly cold nights.

What should people do if they encounter someone who appears to be in distress as a result of the cold?



If you see someone out in the cold who appears confused or disoriented or is unconscious, call 911. Especially when the temperature drops below 22 degrees, the city is on high alert and anxious to find people who might be in trouble. In New York City, police are able to bring people inside against their will. That’s not the case in Boston, but police and EMS and outreach workers have been trained to strongly encourage people to come in from the cold and offer each person a ride to a shelter.

How much of a threat is frostbite and hypothermia to people living indoors but who find themselves unprepared for unexpectedly extreme cold? Any tips?



Wear a hat and cover your head. Most loss of body temperature happens through the head. Wear gloves and warm socks to protect your hands and feet. Wear layers to keep warm. Stay dry. If anything near your skin is wet, the loss of body heat is profoundly increased. And be aware that alcohol makes things worse. There’s the perception that some brandy and spirits will warm you up. Despite that rush of warmth as it goes down, alcohol rapidly accelerates loss of body heat.

Bill Mitchell, a longtime journalist (and college friend of Jim O’Connell), lives at Beacon Hill Friends House and blogs about it with his wife, Carol, at ayearinaroom.com. O’Connell will lead a discussion of the medical risks of homelessness at 7:30 p.m. on Feb. 5 at Beacon Hill Friends House.

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