Older adults break down in extreme heat…"They cannot feel thirst or shed heat"

 (Seoul=News1) Reporter Cheon Sun-hyu = With record heat continuing day after day, seven out of every ten people whose deaths this year are presumed to be heat-related were aged 70 or over. Widening the range to those aged 60 and over, they account for 81% of the deaths, showing that the harm is concentrated among older people.

Older people are especially vulnerable to heat because their ability to sweat and regulate body temperature is reduced and because they feel thirst later. Experts urged that while the heat wave continues, people should take in plenty of fluids even when they are not thirsty and avoid outdoor activity in the middle of the day.

According to the Korea Disease Control and Prevention Agency's 'emergency room surveillance system for heat-related illness', a total of 2,441 people suffered heat-related illness between 15 May and 4 August. Of these, 450 were in their 60s, or 18.4% of the total, the largest share of any age group. They were followed by 305 people in their 70s and 300 aged 80 and over, while those aged 65 and over totaled 825, or 33.8% of the whole.

Relative to population size, however, the risk was highest among those aged 80 and over. Per 100,000 population, heat-related illness was most common in people aged 80 and over, at 12.5 cases, followed by 7.4 among those in their 70s and 5.8 among those in their 60s. Of a total of 21 deaths presumed to be caused by heat-related illness, 15, or 71.4% of the whole, were people aged 70 and over. Widening the range to those aged 60 and over raises the number of deaths to 17 (81.0%), showing that the harm was concentrated among older people.

Older people are far less able to shed heat… their sense of thirst also dulls
Professor Kim Jun-seong of Emergency Medicine at Asan Medical Center cited the decline in temperature regulation with age as the biggest reason older people are vulnerable to heatwaves.

Professor Kim explained, "In older people the sweat glands work less well, so they produce less sweat, and the ability of the blood vessels in the skin to dilate also declines, greatly reducing the body's ability to release heat," adding, "Their sense of thirst also becomes blunted, so in many cases they fail to recognize the signal to take in fluids even when dehydration is already well advanced."

The brain's temperature regulation also deteriorates. As the hypothalamus, which senses and regulates body temperature, becomes less sensitive, the response to changes in body temperature is slower and less accurate, so that even with the same exposure to heat the risk of progressing to heat stroke is far higher than in younger people.

Heat-related illness is divided into heat cramps, heat exhaustion and heat stroke. Heat cramps, in which dehydration causes muscle cramps, are a relatively mild stage, while heat exhaustion brings low blood pressure, dizziness and fatigue. Heat stroke, the most dangerous of the three, is an emergency in which body temperature rises above 40 degrees and impaired consciousness follows; without prompt treatment it can be life-threatening.

In the early stages, people often tire more easily than usual and develop headache, dizziness, nausea or loss of appetite. If body temperature keeps rising, however, sweating decreases or stops, the skin becomes hot, and heart rate and breathing quicken. Clouded consciousness, incoherent speech, confusion about time and place, or convulsions are signs that heat stroke is well advanced.

If heat-related illness is suspected, the person should be moved at once to an air-conditioned room or into the shade to bring their body temperature down. Loosening their clothing and applying wet towels to the neck, armpits and groin, where large blood vessels run, or cooling the body with an electric fan or hand fan helps. If the person is unconscious or responding poorly, however, do not force them to drink; call 119 immediately and have them taken to an emergency room.

Managing dehydration matters even more for hypertension and diabetes patients
Older people with underlying chronic conditions such as hypertension and diabetes need to pay even closer attention to preventing dehydration and managing their blood pressure. Dehydration in older adults can cause changes in blood pressure that add to the strain on the cardiovascular system, and as loss of body water raises blood viscosity, the risk that a clot will form and lead to cerebral infarction or myocardial infarction also grows.

If symptoms such as sudden dizziness, weakness in the arms or legs, slurred speech, difficulty breathing or a crushing chest pain appear, they should not be dismissed as simply the effect of the heat; medical care should be sought at once.

Older people are also vulnerable to dehydration itself. Lee Ji-yeon, Chief of Nephrology at St. Peter's Hospital, explained, "About 7% of inpatients aged 65 and over have in fact been reported to be short of fluids, and dehydration accounts for as many as 1.4% of admissions," adding, "In patients with diabetes in particular, dehydration raises blood glucose and can make the condition worse."

She went on, "People aged 60 and over are vulnerable to dehydration, so particular care is needed in summer," stressing, "Patients with kidney disease, including chronic kidney disease, especially need to consult a specialist and decide on a fluid intake suited to their own condition."

Professor Kim urged, "When a heat wave advisory is in force, people should avoid going out and working outdoors between noon and 4 p.m. as far as possible, and get into the habit of drinking water more often than usual even when they are not thirsty."

He continued, "Older people need to be aware that the ability to regulate body temperature declines with age," stressing, "It is more important than anything that families also look after cooling and fluid intake together and check often on parents or elderly relatives who live alone."