Dehydration, Hyperthermia and Heatstroke: Caring for Older Adults in Summer
Published: 09 October 2023
Published: 09 October 2023
In Australia, heatwaves have caused more deaths than any other natural disaster (DEA 2020).
With older adults over 65 being one of the high-risk groups for hyperthermia (along with babies and young children, pregnant people and those with certain conditions) (Better Health Channel 2022a), knowing how to appropriately care for your older clients during the warmer months is crucial.
Hyperthermia is an umbrella term comprising several heat-related illnesses that are caused by disruption to homeostasis. Hyperthermia occurs when the body is unable to dissipate as much heat as it is absorbing or producing, leading to a thermoregulation failure (NIA 2022; QAS 2022).
Heat-related illnesses include heat syncope, heat cramps, heat oedema, heat exhaustion, dehydration, heat rash, worsening of existing medical conditions and heatstroke (NIA 2022; Better Health Channel 2022a).
Heatstroke is defined by a body temperature of over 40°C. It is the most serious form of hyperthermia and is a life-threatening medical emergency that may lead to multi-organ failure, disability or death. In order to prevent heat exhaustion from progressing to heatstroke, prompt treatment is essential (QAS 2022).
Up to 80% of heatstroke cases result in fatalities (Better Health Channel 2022a).
Older adults are more susceptible to dehydration due to changes in the body that occur with ageing, including decreased thirst sensation and decreased renal perfusion (Picetti et al. 2017).
Poor blood circulation, less efficient sweat glands and overall reduced tolerance to sudden or prolonged temperature changes are also age-related risk factors (NIH 2018; Better Health Channel 2022a).
Other reasons why older adults are more likely to experience hyperthermia include:
(DEA 2020; Aged Care Guide 2022; SA Health 2013)
Despite this, a 2017 study alarmingly found that dehydration was ‘frequently dismissed’ among aged care residents (Miller 2017).
Furthermore, a 2013 study found that while 38% of surveyed older adults had experienced hyperthermia symptoms during recent heatwaves, only 3% were concerned about their health (SA Health 2013).
Causes of hyperthermia include:
(Better Health Channel 2022a)
Factors that may contribute to hyperthermia include:
(CDC 2017; NIH 2018)
Illness | Description | Symptoms | Treatment |
---|---|---|---|
Dehydration | A reduction of fluid present in the systemic circulation causes the heart to work harder to sustain adequate perfusion to vital organs. |
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Heat rash | Skin irritation due to excessive sweating. |
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Heat syncope | Sudden dizziness or fainting caused by vasodilation, which reduces blood flow to the brain (heat causes increased blood flow to the skin and legs). |
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Heat cramps | The tightening of muscles in the arms, legs or stomach, generally caused by a loss of salt and water during strenuous activity in a hot environment. |
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Heat oedema | Swelling in the ankles or feet caused by exposure to heat. |
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Heat exhaustion | A serious type of hyperthermia caused by loss of blood volume from excessive sweating. It may progress into heat stroke if untreated. |
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See below |
Heatstroke | A medical emergency where the core body temperature is more than 40°C. Body systems may begin to shut down. |
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See below |
(Better Health Channel 2022a; NIA 2022; QAS 2022; NSW Health 2022)
Clients may also experience an exacerbation of other existing conditions. This is the most common effect of hyperthermia (Better Health Channel 2022a).
In the case of an emergency, the priority is to cool the client down (Queensland Health 2021).
(Queensland Health 2021; QAS 2022; NSW Health 2022)
It is important to note that the symptoms of heat exhaustion and heatstroke may be similar. However, one significant difference is that a client with heatstroke may have dry skin and not be sweating (Better Health Channel 2022a).
The following tips will help prevent clients from experiencing hyperthermia on hot days:
(DoH 2020; Better Health Channel 2022b; Baptcare 2017)
It’s crucial to identify and treat dehydration early in order to prevent serious complications and severe hyperthermia (Chan et al. 2018; Mayo Clinic 2021).
In fact, even dehydration equal to a loss of 2% of body weight may adversely affect physiological responses and performance (Eat For Health 2021).
Hydration is influenced by physical, mental and behavioural factors that affect the willingness and ability for people to remain hydrated (Miller 2017). A non-modifiable risk factor for dehydration is older age (Burns 2016). However, while it may not be possible to turn back time, nurses can use this information to modify their practice.
In residential aged care, it is recommended that staff perform hourly checks on clients to ensure that they have access to and are assisted with hydration (Burns 2016).
The Nutrient Reference Values for Australia and New Zealand (2021) recommend that:
Note that this recommendation is an average, and evidently, factors such as very hot climates must be taken into account for the individual’s hydration needs (Eat For Health 2021).
Other factors that may cause a client to require additional fluids include:
(Better Health Channel 2021)
Healthcare professionals must be careful to follow any additional hydration needs of the individual, for example, fluid restrictions set by specialists. It is thereby also essential to document fluid balance accurately.
Older adults are at increased risk of hyperthermia. Keeping your clients safe during summer is essential, as heatstroke is a life-threatening emergency.
Question 1 of 3
Which one of the following types of hyperthermia is often caused by physical exertion in warm weather?