Urban Heat and Health (Extended Coverage)

Richard Keller, PhD, Pro­fes­sor, Uni­ver­si­ty of Wis­con­sin; Author, Fatal Iso­la­tion

I want to talk today about that 2003 Euro­pean heat wave, with a par­tic­u­lar focus on Paris. It pushed tem­per­a­tures well above 100° F through­out much of Europe for about two weeks, and evening lows real­ly only dropped to the mid-70s, which left lit­tle respite. This came after two ear­li­er and near­ly equal­ly intense heat waves, which had already left many vul­ner­a­ble Euro­peans on their knees. The con­sen­sus is that high sum­mer heat entailed the excess deaths of some 70,000 Euro­peans that sum­mer, and the August heat wave alone in France killed near­ly 15,000 peo­ple. About 1,000 of them were in Paris, and that makes this the worst nation­al dis­as­ter in French his­to­ry.

To give some per­spec­tive, in a nor­mal peri­od, Paris’s morgue ser­vices shut­tle about 40 bod­ies through­out the city in a giv­en day, and in just three days in August of 2003, they trans­port­ed near­ly 800. The dis­as­ter also struck uneven­ly. About 80% of the mor­tal­i­ty-bur­dened were those over 75 years old. Those in cities also paid a sig­nif­i­cant­ly high­er toll. Paris has about 3% of the country’s pop­u­la­tion, but it suf­fered about 7% total mor­tal­i­ty dur­ing the dis­as­ter, a dis­pro­por­tion­ate bur­den by any mea­sure.

Social inequal­i­ties and vul­ner­a­bil­i­ties were laid bare by the dis­as­ter, and I espe­cial­ly want to address some of the ways in which archi­tec­ture and urban plan­ning might have had some­thing to do with this kind of uneven dis­tri­b­u­tion. There are all kinds of legit­i­mate phys­i­o­log­i­cal and mete­o­ro­log­i­cal rea­sons why the elder­ly in cities, in par­tic­u­lar, might have high­er mor­tal­i­ty than oth­er pop­u­la­tions. As we age, our bod­ies get less effi­cient at ther­mal reg­u­la­tion and sens­ing dehy­dra­tion.

So we’re more vul­ner­a­ble in that respect. Like­wise, the urban heat-island effect plays a crit­i­cal role, and some of the epi­demi­ol­o­gy sug­gests this was at play. A map of excess mor­tal­i­ty by neigh­bor­hood in Paris shows the 13th and 15th arrondisse­ments, which are basi­cal­ly text­book exam­ples of urban heat islands: there’s vir­tu­al­ly no green space; lots of con­crete, lots of waste heat. If you look at some adja­cent neigh­bor­hoods right next to these com­plex­es, you can see more tra­di­tion­al 19th-cen­tu­ry Hauss­mann­ian archi­tec­ture, which actu­al­ly suf­fered sig­nif­i­cant­ly low­er mor­tal­i­ty.

With­out dis­miss­ing the crit­i­cal effect that heat islands might play, there’s more we need to dig into, a huge social com­po­nent to address. There’s plen­ty of mor­tal­i­ty to go around in neigh­bor­hoods marked by the clas­sic Hauss­mann­ian archi­tec­ture that char­ac­ter­izes most of Paris, and indeed you can argue that increased mor­tal­i­ty in these sites is actu­al­ly in many ways a func­tion of the build­ing style itself. If we look at the 19th-cen­tu­ry remak­ing of the city, in a cross-sec­tion of a typ­i­cal Hauss­mann­ian build­ing, we can see the devel­op­ment of a new geog­ra­phy of inequal­i­ty that oper­ates on a ver­ti­cal plane. As you ascend the stair­case in one of these build­ings, you’re actu­al­ly descend­ing the socioe­co­nom­ic lad­der, so when you get to the top, right up under these zinc and alu­minum roofs, the heat loads become high­er, the spaces are small­er, ven­ti­la­tion is less effec­tive, peo­ple become poor­er, and they also become more social­ly iso­lat­ed. In par­tic­u­lar, the elder­ly poor suf­fer from these kinds of con­di­tions with sev­en-sto­ry spi­ral stair­cas­es effec­tive­ly impris­on­ing many of those old­er than 75 with increased dis­abil­i­ties. These spaces also have few­er ameni­ties, with some not even hav­ing run­ning water or toi­lets on the same floor, let alone baths or show­ers. It’s no won­der that the risk of dying in these kinds of con­di­tions is about 133% high­er than those who lived even a sin­gle floor below. There’s a ver­ti­cal geog­ra­phy of vul­ner­a­bil­i­ty that we need to think about as we think about heat islands.

The sec­ond point is, even in neigh­bor­hoods that con­sti­tute true heat islands, there are impor­tant social fac­tors at work that influ­ence urban socia­bil­i­ty. The Olympiades com­plex was built on the site of a for­mer slum that the city razed in the 1960s, and the replace­ment of these for­mer build­ings dis­placed the com­mu­ni­ty, who could no longer afford the high­er rents imposed by the new con­struc­tion. Anoth­er phe­nom­e­non attend­ed the re-com­po­si­tion of the neigh­bor­hood: the shut­ter­ing of many local busi­ness­es. The num­ber of cafés and bak­eries declined by 90%. In the Rue Nationale alone, there were 48 of these cafés that were actu­al­ly replaced by just one. More than mere­ly cof­fee shops, these cafés offered a liv­ing space for peo­ple who suf­fered dai­ly indig­ni­ties of liv­ing in tiny, over­crowd­ed, and unhealthy apart­ments. While the rede­vel­op­ment of the neigh­bor­hood may have dra­mat­i­cal­ly cleaned up the area, it also frag­ment­ed the exist­ing com­mu­ni­ty.

These new con­glom­er­a­tions also engen­der insu­lar­i­ty. With many essen­tial ser­vices locat­ed right on the cam­pus­es, peo­ple tend not to leave. This rein­forces social iso­la­tion, and any adven­ture into the out­side world entails a long wait for an ele­va­tor, fol­lowed by an often cir­cuitous route down to the side­walk. Clos­ing these cen­ters of social life assumes a new impor­tance if we think about these neigh­bor­hoods’ stag­ger­ing mor­tal­i­ty. If you con­sid­er that social iso­la­tion is a crit­i­cal fac­tor that exac­er­bat­ed mor­tal­i­ty risk dur­ing the heat wave, we need to think about how iso­la­tion is becom­ing a way of life for many of the elder­ly.

I want to close with an anec­dote: a café in the 16th arrondisse­ment was a social hub in the neigh­bor­hood where I lived when I was con­duct­ing my field­work. This hap­pens to be in the neigh­bor­hood of the low­est mor­tal­i­ty dur­ing the heat wave. So I stopped here for cof­fee every morn­ing before I set out to do my research, and there was also an old man who came into the café every morn­ing with his dog. Every morn­ing he would hand a lit­tle vial to the bar­tender and then lean back­ward over the bar, and the bar­tender would give him his eye drops — his glau­co­ma med­i­cine. I think this is more than a med­ical action; I think it’s actu­al­ly a symp­tom of a kind of social coher­ence that marks this neigh­bor­hood and that might attest, to some extent, to its low mor­tal­i­ty rate. It sug­gests that we need to con­sid­er not just heat islands but social worlds if we want to under­stand vul­ner­a­bil­i­ty and resilience in a peri­od of rapid cli­mate change. In oth­er words, I think Jane Jacobs was right.


Tom Mat­te, Assis­tant Com­mis­sion­er for Envi­ron­men­tal Sur­veil­lance and Pol­i­cy, NYC Depart­ment of Health and Men­tal Hygiene

Urban den­si­fi­ca­tion has tremen­dous poten­tial ben­e­fits for the larg­er envi­ron­ment, pub­lic health, and sus­tain­abil­i­ty. But it also expos­es urban res­i­dents to cer­tain haz­ards dis­pro­por­tion­ate­ly: not just extreme heat but also air pol­lu­tion, noise, being strand­ed in high-rise build­ings. How do we con­tin­ue to lever­age the ben­e­fits of that com­pact, sus­tain­able urban form while pro­tect­ing and pro­mot­ing pub­lic health, espe­cial­ly among the most vul­ner­a­ble and mar­gin­al­ized pop­u­la­tions?

Heat ill­ness and death fall into two broad cat­e­gories: there’s heat-spe­cif­ic ill­ness, hypother­mia, which can be count­ed. The people’s names can be known. And then there’s an increase in seri­ous ill­ness­es and death from chron­ic health prob­lems like heart dis­ease, lung dis­ease, and so forth. Those excess deaths and ill­ness­es are actu­al­ly much larg­er in num­ber than the heat-spe­cif­ic deaths. When the heat index (tem­per­a­ture and humid­i­ty com­bined) makes it feel like it’s about 95° or above, risks start to rise in a non­lin­ear way: there are on aver­age between 10 and 15 hyper­ther­mia deaths, more like 100 excess nat­ur­al-caus­es deaths, dur­ing extreme heat events. Excess mor­tal­i­ty and mor­bid­i­ty also occur in the sea­son­al hot weath­er that we have in New York City, and that has impli­ca­tions for pre­ven­tion and the built-envi­ron­ment changes we need to make.

The poten­tial for a more cat­a­stroph­ic heat wave is always there. If you apply the mor­tal­i­ty rate from the north­ern Euro­pean and French heat wave to New York City, that would be some­thing like 2,000 deaths from a sin­gle nat­ur­al dis­as­ter. What might cause some­thing like that to hap­pen in New York? It could be the com­bi­na­tion of an extend­ed heat wave and wide­spread pow­er out­ages; dur­ing the 2003 city­wide out­age that last­ed just about 36 hours, there were close to 100 excess nat­ur­al-cause deaths, and excess mor­bid­i­ty and mor­tal­i­ty from that event were not lim­it­ed to low-income neigh­bor­hoods. There’s some evi­dence that it was actu­al­ly neigh­bor­hoods with lots of high-rise build­ings; even more afflu­ent neigh­bor­hoods, had more of an increase in res­pi­ra­to­ry ill­ness dur­ing the 2003 black­out.

Our role in the Health Depart­ment is to use data on health impacts and vul­ner­a­bil­i­ty to inform how the city pre­pares for and responds to heat waves. Most of the peo­ple who die from heat stroke are exposed at home, don’t have work­ing air con­di­tion­ing, or weren’t using it at the time of death. Peo­ple with chron­ic phys­i­cal and men­tal health con­di­tions are almost always present among these hypother­mia deaths. At the neigh­bor­hood lev­el, we see a com­bi­na­tion of mea­sures of social dis­ad­van­tage (pover­ty con­cen­tra­tion, African-Amer­i­can race) as well as phys­i­cal-envi­ron­ment dif­fer­ences (high­er sur­face tem­per­a­tures, less green infra­struc­ture, less veg­e­ta­tive cov­er). We esti­mate about 25% of New York­ers either don’t have or don’t use air con­di­tion­ing at home dur­ing extreme heat; half stay home even when it’s too hot. If we look at the over­lap of that pop­u­la­tion and peo­ple who have a health risk, that’s about a half mil­lion New York­ers. We’ve been try­ing to improve the kinds of mes­sages that go out at the begin­ning of heat sea­son and the audi­ences that they get to, so that peo­ple know what they need to pro­tect them­selves, clients, neigh­bors, fam­i­ly, and friends. We would real­ly ben­e­fit from bet­ter mod­els of the urban heat island and how it affects inte­ri­or tem­per­a­tures and peo­ple on the stret, so that we could com­mu­ni­cate to city lead­ers who have to make invest­ments.

When­ev­er I talk at any sort of cli­mate health meet­ing, there’s always the ques­tion, “Why are you pro­mot­ing air con­di­tion­ing as a pro­tec­tive mea­sure?” In New York City we’re using an enor­mous amount of air con­di­tion­ing. Ener­gy used to cool spaces more than they need is not only strain­ing the elec­tric grid, it’s pro­duc­ing more air pol­lu­tion, because it’s using the peak­ing units that are need­ed to main­tain pow­er on the hottest days of the year, and it’s pro­duc­ing waste heat. Learn­ing how we can change that behav­ior could be low-hang­ing fruit. Cer­tain peo­ple need air con­di­tion­ing; we need to fig­ure out cre­ative ways to get them access to it, either in their unit or in cool­ing cen­ters or lob­bies. But then oth­er peo­ple need to be using air con­di­tion­ing respon­si­bly and need an aware­ness of how there’s an exter­nal­i­ty to using it in a com­mer­cial or res­i­den­tial space.


Melis­sa Umberg­er, Haz­ard Mit­i­ga­tion Project Man­ag­er, NYC Depart­ment of Emer­gency Man­age­ment

When there is an emer­gency, we are the lead coor­di­nat­ing agency for mak­ing sure all the right peo­ple are in the room to col­lect and dis­sem­i­nate crit­i­cal infor­ma­tion to our city part­ners and the pub­lic. We also have exten­sive cam­paigns for prepar­ing the pub­lic for all types of emer­gen­cies. Due to the com­plex­i­ty of cross-cut­ting haz­ard impacts, our agency takes two approach­es to plan­ning: all-haz­ards plans and haz­ard-spe­cif­ic plans. We have a Heat plan for extreme heat events and at the same time a Pow­er Dis­rup­tion plan applic­a­ble to many dif­fer­ent haz­ards; for an extreme event typ­i­cal­ly we acti­vate both pro­to­cols simul­ta­ne­ous­ly. Our acti­va­tion cri­te­ria are a pro­ject­ed increase of a heat index of 100° F or more for any peri­od of time and a heat index of 95° F for two con­sec­u­tive days or more. In 2014 we mod­i­fied some of our pro­to­cols because of cli­mate change and the fre­quen­cy and inten­si­ty of heat waves.

Our Advanced Warn­ing Sys­tem has a two-pronged approach: con­fer­ence calls and blast e-mails to our part­ner agen­cies, ser­vice providers, and umbrel­la orga­ni­za­tions that serve the needs of pop­u­la­tions that have dis­abil­i­ties or oth­er access and func­tion­al needs. We’re pro­vid­ing tar­get­ed infor­ma­tion, usu­al­ly includ­ing a fore­cast from the Nation­al Weath­er Ser­vice, heat tips, pre­pared­ness mea­sures that indi­vid­u­als can do, and the loca­tion of our cool­ing cen­ters. Our “Beat the Heat” guide, avail­able in 91 dif­fer­ent lan­guages, pro­vides pre­pared­ness tools, things like pro­mot­ing the use of air con­di­tion­ing and check­ing in on your friends and fam­i­ly, espe­cial­ly those that might be vul­ner­a­ble. Cool­ing cen­ters are air-con­di­tioned facil­i­ties, open and free to the pub­lic; they typ­i­cal­ly already serve the com­mu­ni­ty as a library, senior cen­ter, or com­mu­ni­ty cen­ter. We lever­age our part­ner agen­cies: the Depart­ment for the Aging, the New York City Hous­ing Author­i­ty (NYCHA), and the Depart­ment of Youth and Com­mu­ni­ty Devel­op­ment, who will use their facil­i­ties for a dual pur­pose. We also increase our home­less out­reach; the Depart­ment of Home­less Ser­vices has a Code Red, send­ing out mon­i­tor­ing teams on the street. Our Watch Com­mand Office receives infor­ma­tion 24/7 from Con Edi­son and oth­er enti­ties, will get infor­ma­tion about pow­er out­ages and volt­age reduc­tions; dur­ing extreme heat events we may send a liai­son from our agency over to Con Edi­son to mon­i­tor that sys­tem and coor­di­nate resource requests.


Sab­ri­na McCormick, PhD, Asso­ciate Pro­fes­sor of Envi­ron­men­tal and Occu­pa­tion­al Health, George Wash­ing­ton Uni­ver­si­ty; Film­mak­er

I’m speak­ing to what I have seen so far is a minor­i­ty of peo­ple inter­est­ed in this sub­ject. As a qual­i­ta­tive soci­ol­o­gist who spends a lot of time going to cities across the coun­try, I can tell you that you are ahead of the curve. One research project is a focused deep dive on heat and vul­ner­a­ble pop­u­la­tions in New York, Philadel­phia, Detroit, and Phoenix in a col­lab­o­ra­tion with folks at the Uni­ver­si­ty of Michi­gan and Har­vard; there’s a more recent project on cli­mate adap­ta­tion in Tam­pa, Raleigh, Port­land (Ore.), Los Ange­les, Boston, and Tuc­son. We’re look­ing at how city offi­cials, NGOs that work with them, and gov­ern­ments more gen­er­al­ly per­ceive and address heat risk, and how vul­ner­a­ble pop­u­la­tions per­ceive their own risk and respond to it. There’s been lim­it­ed con­cern about heat, but since I’ve been work­ing on this for almost a decade, this has shift­ed, and we see some cities becom­ing more and more con­cerned. Hav­ing said that, their actions to address heat risk have been lim­it­ed: there’s a decent amount of plan­ning in some places, but less imple­men­ta­tions of heat-adap­ta­tion pro­grams.

Vul­ner­a­ble pop­u­la­tions, espe­cial­ly peo­ple over 65 liv­ing in dense, hot­ter areas, where I”ve done the most inter­view­ing, tend to not rec­og­nize heat as a risk fac­tor. When they do, they engage in self-pro­tec­tive reac­tions: they drink water, stay inside, take a cold show­er, use a fan; they some­times go to a cool­ing cen­ter, a park, or shop­ping; and some­times they use their AC. Res­i­dents have expressed con­cerns about pay­ing for the elec­tric­i­ty, or risks to the air con­di­tion­er and poten­tial fire in old build­ings, when it’s on a long time. There are pre­con­cep­tions and stigma­ti­za­tions of cool­ing cen­ters in some places; vul­ner­a­ble pop­u­la­tions can think a cen­ter is occu­pied by – and this is their lan­guage – “drug addicts, peo­ple on parole, and alco­holics.” There are places where peo­ple feel uncom­fort­able going for a num­ber of rea­sons. There are also trans­porta­tion bar­ri­ers. It’s very impor­tant that we empha­size, as I think this com­mu­ni­ty prob­a­bly does, devel­op­ing cool­ing resources that are not just access to cool­ing cen­ters or access to air con­di­tion­ing, because we face major obsta­cles in actu­al­ly con­vinc­ing peo­ple that they’re at risk and that they can use their AC.

In basi­cal­ly every city where I’ve done research I see dis­junc­ture between pub­lic-health offi­cials and urban plan­ners. There is a con­stant need to inform the pub­lic and all those whom we work with about the risk of heat waves; it’s a risk that I find peo­ple chron­i­cal­ly under­es­ti­mate. I’m also a film­mak­er, and I was a pro­duc­er on a sto­ry in The Years of Liv­ing Dan­ger­ous­ly, a Show­time series about cli­mate change. I pro­duced the sto­ry with Matt Damon as a cor­re­spon­dent inves­ti­gat­ing heat risk in Los Ange­les. We intro­duce him to a woman who has gone into preterm deliv­ery dur­ing a heat wave; she has no idea that heat is a risk fac­tor. She is rushed to the emer­gency room and put on two bags of saline, and they pre­vent this preterm birth (increased rates of preterm deliv­ery dur­ing heat waves is an increas­ing con­cern, espe­cial­ly in urban areas). She tells Matt this sto­ry, and his face gets shocked and blank; he says “You know what? That exact same thing hap­pened to my wife.” Peo­ple who are the most vul­ner­a­ble and peo­ple who in some ways are the least vul­ner­a­ble real­ly know very lit­tle about heat. We need to be con­tin­u­al­ly edu­cat­ing both city-lev­el deci­sion mak­ers and vul­ner­a­ble pop­u­la­tions around the world.


Elan Levy, MD, Attend­ing Physi­cian, Emer­gency Depart­ment, Lenox Hill Hospital/Lenox Health Green­wich Vil­lage, North Shore-LIJ Health Sys­tem

Our body tem­per­a­ture is main­tained by bal­anc­ing heat load with heat dis­si­pa­tion. We have a remark­able resilience against cold but can only tol­er­ate minor fluc­tu­a­tion with tem­per­a­ture increase with­out devel­op­ing sys­temic dys­func­tion. As our core tem­per­a­ture ris­es, the hypo­thal­a­mus stim­u­lates the ner­vous sys­tem to cause changes in the skin and the way we sweat. Evap­o­ra­tion, when water vapor­izes from our skin and our res­pi­ra­to­ry tract, is the body’s most effec­tive mech­a­nism for dis­si­pat­ing heat. Dur­ing exer­cise our body needs an intact car­dio­vas­cu­lar sys­tem, which uses blood to trans­fer heat from our core to the skin, where these mech­a­nisms for heat dis­si­pa­tion can take effect. When ambi­ent tem­per­a­ture is high­er than our core tem­per­a­ture, or when humid­i­ty exceeds 75%, these means of heat dis­si­pa­tion are no longer effec­tive. Tem­per­a­ture ele­va­tions also cause a rise in oxy­gen con­sump­tion as well as the meta­bol­ic rate and also cause cer­tain enzymes to cease to func­tion. The cells in the brain, liv­er, and periph­er­al vas­cu­lar sys­tem are sus­cep­ti­ble to increased heat.

The most impor­tant heat-relat­ed ill­ness is heat stroke, a mul­ti­sys­tem, life-threat­en­ing illess that  occurs in the set­ting of extreme heat that can­not be dis­si­pat­ed. It’s char­ac­ter­ized by cen­tral-ner­vous-sys­tem dys­func­tion, which man­i­fests with dis­ori­en­ta­tion, headache, and irra­tional behav­ior and can even pre­cip­i­tate to seizures and coma. There has to be a core tem­per­a­ture above 104° F and expo­sure to severe envi­ron­men­tal heat. There’s also a high mor­tal­i­ty risk asso­ci­at­ed with heat stroke: any­where from 21% to 63%. The two types are exer­tion­al and nonex­er­tion­al (or clas­sic) heat stroke. Exer­tion­al heat stroke is typ­i­cal­ly in an unac­cli­ma­tized young per­son exposed to a heat stress over just a few hours; clin­i­cal­ly they’re still able to pro­duce sweat, as opposed to clas­si­cal heat stroke, where it’s either the very young or very old, it’s a grad­ual onset over sev­er­al days, and they present severe­ly dehy­drat­ed, typ­i­cal­ly with dry, hot skin. Minor heat-relat­ed ill­ness­es include heat exhaus­tion and heat syn­cope, which may mim­ic heat stroke or be pre­cur­sors for it but lack that ele­va­tion in core tem­per­a­ture, along with heat cramps, tetany, or rash.

Acclima­ti­za­tion is the body’s abil­i­ty to improve its response in tol­er­ance to heat stress over time and is much more impor­tant with exer­tion­al heat ill­ness. It typ­i­cal­ly requires one to two weeks but can take as long as 60 days; some of the phys­i­o­log­ic changes include increase in blood vol­ume, improved blood flow to the skin, a low­er thresh­old of the ini­ti­at­ing of sweat­ing, and a low­er con­cen­tra­tion of salt and sweat.

Cri­te­ria that put some­one at risk for clas­si­cal heat stroke are age old­er than 70 and chron­ic med­ical con­di­tions such as car­dio­vas­cu­lar dis­ease, res­pi­ra­to­ry dis­ease, phys­i­cal debil­i­ties, men­tal ill­ness, and obe­si­ty. Risk groups also include those with a lack of access to air con­di­tion­ing, the social­ly iso­lat­ed, those who are unable to care for them­selves, users of recre­ation­al or pre­scrip­tion drugs, and chil­dren. Chil­dren have a high­er basal meta­bol­ic rate, which caus­es increased heat pro­duc­tion; a high­er sur­face-area-to-mass ratio, which caus­es greater heat absorp­tion from the envi­ron­ment; and a small­er absolute cir­cu­lat­ing blood vol­ume, which lim­its the trans­fer of blood from the core to the periph­ery, the main mech­a­nism of heat dis­si­pa­tion. They also sweat at a low­er rate, they don’t ade­quate­ly replen­ish flu­id loss­es, and the acclima­ti­za­tion process occurs at a much low­er rate than an adult’s.

Many med­ica­tions and sub­stances can put some­one at risk for heat stroke: alco­hol, anti­cholin­er­gics, seizure med­ica­tions, psy­chi­atric med­ica­tions, decon­ges­tants, diuret­ics, anti­hy­per­ten­sives, stim­u­lants, and anti­his­t­a­mines. These are used to treat a vari­ety of ill­ness­es, includ­ing car­dio­vas­cu­lar, neu­ro­log­ic, and psy­chi­atric dis­eases; they’re often tak­en togeth­er in com­bi­na­tion. Gen­er­al­ly speak­ing, they can cause dehy­dra­tion, con­fu­sion, kid­ney injury, and impaired ther­moreg­u­la­tion. In the emer­gency depart­ment, one would see an elder patient typ­i­cal­ly with numer­ous med­ical con­di­tions and a myr­i­ad of med­ica­tions, usu­al­ly liv­ing alone and found unre­spon­sive by a fam­i­ly mem­ber, care­tak­er, pri­ma­ry med­ical respon­der, or even super­in­ten­dent. It’s typ­i­cal­ly on a hot or humid day in a place that lacks a func­tion­al air-con­di­tion­ing unit.

The clin­i­cal pre­sen­ta­tion is that they’re con­fused, they have a fever, their skin is hot and dry, and they have a low blood pres­sure and high heart rate. This can mim­ic oth­er pre­sen­ta­tions we see in the emer­gency depart­ment, so it’s impor­tant for us to be cau­tious and thor­ough when eval­u­at­ing them. The main­stay of emer­gency treat­ment is the ABCs: air­way pro­tec­tion, mon­i­tor­ing the breath­ing, and cir­cu­la­tion. Evap­o­ra­tive cool­ing is the most suc­cess­ful method of treat­ing clas­si­cal heat stroke: dis­rob­ing the patient, spray­ing with luke­warm water, and using a fan to blow water over the moist skin (cold-water immer­sion is less effec­tive due to the mon­i­tor­ing devices on these patients). Ancil­lary icepacks are use­ful, as well as cool intra­venous flu­ids and saline; tem­per­a­ture mon­i­tor­ing is of the utmost impor­tance, with a goal of less than 101°F. Workup con­sists of blood counts, urine test­ing, and imag­ing. The mor­tal­i­ty rate ranges from 21% to 63%, cor­re­lat­ing with the degree of tem­per­a­ture ele­va­tion, time to ini­ti­a­tion of cool­ing, and num­ber of organs affect­ed. Com­pli­ca­tions include but are not lim­it­ed to res­pi­ra­to­ry fail­ure, arrhyth­mias and car­dio­vas­cu­lar col­lapse, and kid­ney and liv­er dys­func­tion.

Pre­ven­tion of heat stroke should be a pub­lic-health con­cern and a mul­ti­dis­ci­pli­nary approach. As gen­er­al rec­om­men­da­tions for patients and their care­tak­ers: rest, drink cool non­al­co­holic bev­er­ages, wear light­weight cloth­ing, remain indoors dur­ing the hottest times of the day, lim­it stren­u­ous activ­i­ty, facil­i­tate trans­port to air-con­di­tioned loca­tions, and watch for signs of heat exhaus­tion. If these are present in some­one that you know, please expe­dite removal of the per­son from that envi­ron­ment and con­tact with emer­gency med­ical ser­vices.

Our own insti­tu­tion is New York City’s first free­stand­ing emer­gency depart­ment, with a vol­ume of 30,000 vis­its last year; dur­ing times of dis­as­ter, we would quick­ly dis­charge any­one in the ED through safe mea­sures and pre­pare for a mas­sive influx of new patients. In a mas­sive heat wave, those with minor ill­ness­es would be cared for in our depart­ment, and those need­ing an imme­di­ate high­er lev­el of care or sta­bi­liza­tion would be placed in our resus­ci­ta­tion room and tagged with the  New York State Evac­u­a­tion of Facil­i­ties in Dis­as­ter Sys­tem (EFINDS) for loca­tion and track­ing through­out the health com­merce sys­tem. The take-home points here are to under­stand the dif­fer­ences between exer­tion­al and nonex­er­tion­al heat stroke, rec­og­nize at-risk pop­u­la­tions and risk fac­tors, and under­stand some pre­ven­ta­tive mea­sures for high-risk pop­u­la­tions.