Process ranges from minor cramps to rash, heat exhaustion, and heat stroke.
Heat related disease is the most common cause of severe weather fatalities in the United States.
Climate change is causing an increase in the average temperature and is increasing the frequency, duration, and intensity of extreme heat events, resulting in unprecedented levels of heat exposure.
The past seven years have been the hottest on record.
In the past 20 years there has been a 54% increase in heat related mortality among persons older than 65 years, and more than 1/3 of all global warm season heat related deaths are attributed to climate change.
0.02 deaths per 100,000 workers annually.
Between 1992 and 2019 more than 900 US workers died in almost 80,000 were seriously injured because of extreme heat exposure.
Humans thermoregulate through behavioral and autonomic mechanisms such as vasodilatation and sweating to maintain core internal temperature of approximately 37°C.
Metabolic activity generates a heat load, and exogenous heat from the environment adds to the total heat burden that must be managed.
Higher humidity levels exacerbate the challenges of dissipating heat.
Under heat loads resulting from exogenous heat, endogenous heat, or both, the thermoregulatory ability may become strained or overwhelmed resulting in a spectrum of heat related processes.
Heat related diseases range from non-threatening processes like heat exhaustion, heat syncope, heat edema, heat cramps, and heat rash to life-threatening heat stroke.
Deaths occur in agriculture, fishing, forestry and hunting industries.
The risk of dying for farm workers due to heat exposure is 20 times higher than in all US civilian workers.
Crop workers have an annual fatality rate of 0.39 deaths per 100,000.
Typical deaths occur among male crop workers aged 24-54 years.
Heat related disease is a leading cause of death and disability among US high school athletes.
High temperatures lead to rising core body temperatures and heat stress, heat exhaustion, cramps, heat stroke, or death.
Estimated average annual number of heat associated time-loss illnesses of 9237 among US high school athletes.
5,946 persons treated in US EDs each year for heat illness sustained while participating in a sport or recreational activity, for estimated annual rate of 2 visits per 100,000 population-72.5% males, 35.6% aged 15-19 years, and 7.1% required hospitalization.
Most frequent in summer months.
Without prompt management can result in organ failure, brain damage and mortality.
All cases are preventable.
Heat stress and dehydration have been linked with acute kidney injury and US farmworkers.
Associated with dehydration, nausea, vomiting, headache, dizziness and altered mental status.
clinical manifestations of heat related illnesses vary by severity of the process.
Heat stroke is characterized by the triad of hyperthermia, neurologic abnormalities, and recent exposure to hot weather, physical exertion, or both.
Can lead to multiple organ system dysfunction from direct effects of heat and the body’ inflammatory response.
Associated with altered mental status, renal failure, coagulopathy, cardiovascular collapse, and an inflammatory response.
Older adults are more vulnerable to heat related complications.
Older patients are at greater risk based on social and behavioral factors, increased likelihood of being alone, being homebound, or taking medications that interfere with fluid balance.
Many illnesses are heat sensitive meaning that they are exacerbated or triggered by exposure to heat: ischemic heart disease, cardiac arrhythmias, ischemic stroke, asthma, COPD, respiratory tract infections, hyperglycemia, kidney failure, neuropsychiatric disorders, and adverse birth outcomes.
The risk of heat related illness results through a combination of individual susceptibility, endogenous and exogenous heat exposure, and sociocultural factors that affect the ability to adapt.
Older individuals, young children, infants, pregnant women, persons with pre-existing medical conditions, including obesity, outdoor workers, and athletes are at an increased risk as are persons living in low income households in some communities of color.
Heat related risk vary by individual exposure according to geography, occupation, social isolation, and time spent outdoors or in areas that amplify heat, and in areas with less green space.
Urban heat islands refer to areas of densely built infrastructure which absorbs and then re-emits heat from the sun resulting in islands of higher temperatures which can be 1 to 7°F hotter, on average than outlying areas.
They also have much higher nighttime temperatures as a result of re-radiation heat from the surrounding environment.
In the US these heat islands are disproportionately inhabited by low income Black communities and other underrepresented racial and ethnic groups.
Heat related illness may occur in the absence of a heat wave, and a high index of suspicion is warranted in the context of the suggested symptoms.
Heat exhaustion, on the continuum with heat stroke, can be managed by passive cooling and rehydration in mild cases, and in moderate cases managed with convective cooling, infusion of cold fluids, and close monitoring.
Heat stroke is managed with acute resuscitation measures followed by rapid cooling, reducing the core body temperature to 38 to 39°C, ideally within 30 minutes after presentation.