Baby, it's hot outside (part one of two)

During 2004–2018, an average of 702 heat-related deaths (415 with heat as the underlying cause and 287 as a contributing cause) occurred in the United States annually, according to the CDC in its "Morbidity and Mortality Weekly Report". In it the CDC states that natural heat exposure was a "contributing cause of death attributed to certain chronic medical conditions, alcohol poisoning, and drug overdoses."

But it is not 2018 anymore, and heat deaths along with extreme heat, are accelerating. (As if on cue, a few hours after I published this the BBC and CNN reported that 1,000 persons have died from the heat on a Hajj pilgrimage to Mecca.) At least as importantly, areas with high humidity such as ours - particularly over the past several days - are fraught this time of year. The higher the humidity, the less we are able to sweat and cool ourselves.

CDC's health scientist Ambarish Vaidyanathan, of the Climate and Health Program with the National Center for Environmental Health, spoke to me today about the risks of extreme heat and also anecdotally, about the empirical data we are all accruing here in Connecticut this week.

To gauge our heat risk, Nutmeggers can log on to a brightly colored, deceptively beautiful CDC site to assess health risk from heat in their city. Called NWS Heat Risk, the index forecasts risk of heat-related impacts to occur over 24 hours. Also known as the "apparent temperature", the heat index is what the temperature feels like to our bodies when relative humidity is combined with the air temperature. The index was created in concert with the National Oceanic and Atmospheric Association (NOAA) with data from the CDC. HeatRisk takes into consideration:

- How unusual the heat is for the time of the year

- The duration of the heat including both daytime and nighttime temperatures

- If those temperatures pose an elevated risk of heat-related impacts based on data from the CDC

Dr. Vaidyanathan explained why a very hot and humid day at the beginning of summer or late spring can be so much more devastating than a similar day in August. An "out of season" extreme heat event can be devastating because "in terms of acclimatization*, it takes a couple weeks to get used to these high levels so if you have a hot day in the early part of summer - people who aren’t acclimatized* to it [will struggle]."

CDC has dileniated how struggle can be deadly, particularly for those with chronic medical conditions such as heart disease or respiratory or renal issues, and of an older age. In a paper called "Assessment of extreme heat and hospitalizations to inform early warning systems", Dr. Vaidyanathan and colleagues present several charts and graphs to illustrate their point about links between heat, illness and hospitalization or ER visits.

As the National Weather Service (NWS) asserts, extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities" and heat stress multiplies the greater the number of consecutive hot days.

It is toughest on the vulnerable in any setting: in rural locales additional factors such as social isolation and lack of transport or services can put individuals at risk; while the the NWS stresses that in urban settings, with high rise structures, the so-called "urban heat island effect" may increase the risk of heat illness substantially. According to the Environmental Protection Agency (EPA), "'Urban heat islands' occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat. This effect increases energy costs (e.g., for air conditioning), air pollution levels, and heat-related illness and mortality."

Monday, part two: delving into the why behind our risk.

* In a prior version of this blog, the writer used the word "acclimated" by mistake. Apologies for the error.

Photo: "A Connecticut Life", Wikimedia Commons Images