As extreme heatwaves become more frequent worldwide, the elderly population is facing a significant health threat. A study led by Stanford University in the United States has found that individuals over the age of 60 have a much lower tolerance for temperature than previously thought. The recent heatwaves in Europe have led to alarming reports of “excess deaths” in France and the UK, highlighting this issue.
In the past, scientists often underestimated the vulnerability of the elderly population when predicting human heat tolerance by using standards based on healthy young individuals.
The research, led by Stanford Health Policy researchers Qinqin Kong and Dr. Eran Bendavid, was published on August 17 in “The Lancet Planetary Health” journal.
The study explicitly stated that taking into account the physiological fragility of different age groups would result in a wider geographical area experiencing intolerable high temperatures, longer durations of heatwaves, and a much larger population impacted than previously expected.
With the rapid aging of the global population, it is projected that by 2050, the global population over 60 years old will exceed 2.1 billion. This means that the heat-related health crisis for the elderly will reach an unprecedented scale.
The research team warns that for every 1°C increase in global temperature, approximately one billion people may be exposed to extreme high temperatures for at least 180 hours annually, with the elderly bearing the heaviest burden. If temperatures continue to rise, tropical and subtropical regions may become uninhabitable.
The core of the deadly crisis lies in “Uncompensable Heat Stress” (UHS) – when environmental temperatures and humidity are too high, causing the body’s cooling mechanisms such as sweating and vasodilation to be overwhelmed, leading to a loss of the body’s ability to self-regulate temperature, potentially resulting in death.
UHS is not determined by a single fixed temperature but is the result of a combination of high temperatures, humidity, age, health conditions, and hydration levels. Once this threshold is crossed, the body can no longer maintain heat balance, and there is no safe exposure limit. If the environmental conditions are slightly above the threshold, the body’s core temperature could rise to heatstroke or organ failure levels within 3 to 10 hours.
The research team explained that due to the decline in sweat gland function, reduced cardiac capacity, and diminished vasodilation in older individuals, their ability to regulate body temperature is limited, making them more vulnerable to frequent and widespread UHS threats compared to younger individuals.
The warning from this study has been confirmed in the physical environment of Europe. According to the French Public Health Agency, during the heatwave from June 17 to July 2, a total of 21,674 deaths were reported in 92 affected provinces in France, exceeding expectations by at least 5,764 excess deaths (a 36% increase).
This marks the highest excess mortality rate during a single heatwave in France since 2003, with individuals aged 75 and above accounting for nearly two-thirds of the excess deaths (at least 3,719 cases), and the excess mortality rate in the Paris region (Île-de-France) soaring by 81%.
A similar situation occurred in the UK. The UK Health Security Agency reported that the two heatwaves in May and June this year resulted in 2,877 excess (or heat-related) deaths in the UK, nearly double the number in the summer of 2025 (1,504 people). Authorities are concerned that 2026 may set a new record for heat-related deaths in the UK.
Dr. Simon Williams, a researcher at Swansea University in the UK specializing in the health effects of high temperatures, emphasized the growing threat of heatwaves and extreme heat to human health, especially highlighting the increased vulnerability of the elderly.
Caroline Abrahams, Charity Director at Age UK, emphasized the need for global attention to the actual threat of high temperatures to the elderly. She stated that high temperatures not only exacerbate existing chronic health issues in the elderly but also make it more difficult for aging bodies to adapt to extreme heat and cold.
Dr. Hilary Williams, Clinical Vice President of the UK’s Royal College of Physicians, warned from a clinical perspective that extreme heat is a serious patient safety issue.
She pointed out that high temperatures often lead to elderly patients being hospitalized due to dehydration, fainting, or the exacerbation of pre-existing cardiovascular and renal diseases. Managing multiple chronic conditions simultaneously is already challenging, and when a patient’s ability to regulate their temperature deteriorates, medical interventions become even more complicated.