Module 2 Week 5 Older people and heat stress

 Goal: The student can explain why older people are more susceptible to heat stress

In this week we will focus on the risks that Mrs. Davies faces in times of heatwaves. In weeks 1 2 and 3 you got acquainted with the direct and indirect effects in general. There are however vulnerable groups to heat stress. Older people are one of them.  In the article by Meade (2020). https://doi.org/10.106/j.envint.2020.105909 clearly described how heath does influence older people's health. Also, the article in the Lancet by Watts et all 2020 https://doi.org/10.1016/s0140-6736(20)32290-X may be interesting. If you have read the articles above you have come across with the following figure. What is the message that brings the following figure along according to you?

 


Figure Global heat-related mortality for populations older than 65 years. Source: Watts et all 2020

 

 

How the older persons respond to heat

Ageing is associated with reductions in sweat production, a reduction in whole-body sweat rate and limiting the potential for evaporative heat loss. Compared to younger persons, older individuals exhibit smaller increases in cardiac output during heat stress, limiting elevations in skin blood flow. Age-related central cardiac dysfunction also contributes to inadequate cardiovascular responses to heat exposure. Elevations in cardiac output during heat stress are blunted in older adults. Finally, ageing is associated with impaired autonomic regulation of blood pressure, which may further compromise the systemic cardiovascular response and maintenance of blood pressure during heat stress

Altered body fluid regulation renders older adults at increased susceptibility for dehydration. This is particularly relevant given their lower total body water and intravascular volume.  Despite this, the daily fluid intake of older adults is generally within normal ranges in non-heat-stressed conditions. Thus, community-living older individuals are not typically hypohydrated, even though often is reported to the contrary. It should be noted that older adults undergo greater voluntary dehydration during heat exposure compared to their younger counterparts and oral rehydration is delayed following heat stress and/or water deprivation. Thus, even healthy older adults are at increased risk of dehydration during prolonged and repeated heat exposure, as occurs during a heatwave.

 


Figure: Increased risks of heat stress in older people. Source, Meadea et al. 2020.

 The above is quite a technical explanation, the next video explains it differently:

 

 


Now, let us meet Mrs. Davis:

Mrs. Davis is an 80-year-old woman who lives in a small house in the heart of the city with her beloved dog, Charlie. She had been married to her husband, who had passed away five years ago, and since then, she has been living alone with Charlie, who is her constant companion. Mrs Davis is a very independent woman who has always taken care of herself and had never wanted anyone's help, even in her old age.

However, during the hot summer months, Mrs. Davis often forgets to drink enough water and ends up feeling dizzy and dehydrated. Despite her husband's passing, she refuses to move to a cooler place or let anyone help her. She has lived in that house for more than 50 years, and it has many memories for her. She is not ready to leave it, nor is she willing to compromise her independence.

Mrs. Davis's daughter, Sarah, is worried about her mother's health and tries to persuade her to move in with her family or to at least accept some help during the heat waves. However, Mrs. Davis is adamant that she does not want to be a burden on anyone and insists that she can take care of herself and Charlie.

One day, Sarah visited her mother and found her lying on the floor, unconscious. She was lying in her bedroom, where the temperature was a few degrees higher compared to her living room. She had collapsed due to dehydration, and her dog, Charlie, was by her side, barking frantically. Sarah rushed her mother to the hospital, where she was treated for dehydration and heat exhaustion. After a few days, she was able to return home. The doctors advised Sarah to make sure her mother drank enough water and to keep a check on her during future heatwaves.

Knowledge check.

1: Describe the risks that Mrs Davies faces in times of heatwaves. Be as specific as possible.

(h5p card: Module 2 5.1)

Answer 1:

The process of ageing can impair the body's ability to regulate temperature, potentially diminishing the perception of heat and hampering the appropriate behavioural responses in older individuals. This can result in an increased susceptibility to heat-related illnesses and fatalities among the elderly population. Older persons face heightened risks due to various factors including impaired thermoregulatory mechanisms such as reduced sweating and skin blood flow, chronic dehydration, the presence of multiple long-term illnesses (particularly cardiopulmonary disease, diabetes, and dementia), medication usage, disabilities, dependency on others for daily activities, and potentially social isolation.

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Última modificación: miércoles, 13 de noviembre de 2024, 13:56