Urgent Heatwave Alert: Protecting Health Amidst Extreme Temperatures

Health authorities and medical experts are urging the public to take precautions as high temperatures pose significant health risks, particularly for vulnerable populations.

The warnings emphasize how extreme heat impacts the body, the critical role of certain medications, and essential safety measures to prevent heat-related illnesses.

Understanding the Body's Response to Extreme Heat

The human body primarily dissipates heat through the skin, accounting for approximately 90% of heat loss via sweating and increased blood flow to the extremities. This process demands increased effort from the heart, which works harder to divert blood to the skin for cooling while maintaining oxygen supply to vital organs.

This heightened cardiac activity can lead to a drop in blood pressure unless the heart rate compensates. Individuals with pre-existing heart conditions face an elevated risk of cardiac events, such as heart attacks, under these circumstances.

Warm evening temperatures that prevent overnight cooling can significantly impact both physical and mental health. This can result in increased hospital admissions for cardiac and kidney problems, geriatric issues, and falls related to dizziness. It's also important to remember that ambient temperatures, typically recorded in the shade, can be up to 15°C lower than temperatures experienced in direct sunlight.

Who is Most at Risk?

Certain groups are at a heightened risk during periods of extreme heat:

• Older Adults: Age-related physiological changes reduce the body's ability to regulate temperature effectively. Blood flow to the skin and the sweating response become less efficient, causing the body to retain heat. The increased cardiovascular strain can exacerbate underlying conditions such as heart, lung, or kidney diseases, and diabetes. Individuals over 75 years old often experience diminished sweating ability. Social factors, including concerns about energy costs, living alone, reduced mobility, or cognitive conditions like dementia, can also hinder risk assessment and consistent fluid intake.

• Individuals on Medication: Many prescription and over-the-counter drugs can impair the body's ability to regulate temperature, increase dehydration risk, or heighten sun sensitivity.

• Individuals with Pre-existing Conditions: Those with heart disease, high blood pressure, diabetes, lung disease, or kidney problems are more susceptible to severe health complications.

Medication Management in High Temperatures

Certain medications can interfere with the body's thermoregulation processes or increase vulnerability to heat-related illnesses.

Medication Interactions and Risks

• Thermoregulation Impairment: Some drugs, including those for mental health disorders, ADHD, heart disease, high blood pressure, diabetes, migraines, allergies, and constipation, can alter sweating patterns or the body's cooling capabilities. Specific medications like diuretics, beta-blockers, some antidepressants, and anticholinergic drugs are noted for their potential to impair cooling mechanisms.

• Dehydration Risk: Medications can contribute to dehydration, which further increases susceptibility to heat stress, heat exhaustion, and heatstroke. Heart and diabetes medications, in particular, can lead to acute kidney injury if dehydration occurs while maintaining dosages.

• Sun Sensitivity: Certain medications, such as some for acne, non-prescription painkillers, and antihistamines, can increase sensitivity to sunlight, necessitating additional sun protection.

The Pharmacy Guild of Australia advises individuals to review their medications and consult a general practitioner or pharmacist regarding potential heat-related risks and necessary precautions. Consumer Medicine Information (CMI) for medicines provides details on possible side effects. Individuals are advised to continue using prescribed medicines while implementing extra precautions in hot conditions.

Proper Medication Storage

Correct storage of medication is essential, as active ingredients can degrade when exposed to extreme temperatures, potentially rendering them less effective. Most tablets require storage below 30°C or 25°C in a cool, dry place away from direct sunlight.

Certain medications, including insulin, weight-loss injections, and liquid antibiotics, must be refrigerated. Storing medication in a car's glove box is discouraged due to significant temperature fluctuations. If there are concerns about medication degradation due to improper storage, a replacement should be sought from a local pharmacy.

Recognizing and Preventing Heat-Related Illnesses

Recognizing the symptoms of heat-related illnesses and knowing when to seek medical attention is crucial.

Identifying Heat-Related Illnesses

• Heat Stress: Symptoms include tiredness, dizziness, weakness, muscle cramps, irritability, and general discomfort. In older adults, early signs may also include unusual tiredness, lethargy, loss of balance, confusion, shortness of breath, or changes in urine indicating dehydration and kidney strain. These signs indicate a need for rest and rehydration.

• Heat Exhaustion: If heat stress is not addressed, it can progress to heat exhaustion. Symptoms include core body temperatures up to 38°C, reduced sweating due to fluid loss (though heavy sweating can also occur), nausea, vomiting, headaches, and fainting. This condition requires fluids and rest in a cool environment.

• Heatstroke: Untreated heat exhaustion can lead to heatstroke, a life-threatening medical emergency. Core body temperatures can reach 40.5°C or higher. Individuals may experience confusion, reduced alertness, slurred speech, hot and red skin, and an absence of sweating due to severe dehydration, indicating a failure of the body's heat regulation. Immediate medical attention is required.

Safety Recommendations and Prevention

To mitigate the effects of extreme heat, health officials advise the following strategies:

• Stay Hydrated and Seek Shade: Consume adequate fluids and limit exposure to direct sunlight.
• Utilize Air Conditioning: Air conditioning is highly effective for cooling. If home air conditioning is unavailable, spend time in public cool spaces like shopping centres or libraries. Setting air conditioners to 26–27°C and using a pedestal fan can reduce electricity consumption while maintaining comfort.
• Enhance Fan Effectiveness: For those without air conditioning, fans can help. Wetting the skin or clothing combined with a fan boosts evaporative cooling. However, for older adults, fan effectiveness may decrease between 33°C and 37°C, and above 37°C, fans might potentially increase body temperature if sweating is insufficient.
• Direct Cooling Methods: Immersing hands and forearms in cool tap water for ten minutes every half hour has been shown to lower body temperature and reduce cardiac strain.
• Community Alertness: Individuals are encouraged to check on older family members and neighbors during heatwaves.
• Sun Safety: Practice sun safety measures.
• Consult Professionals: Consult a general practitioner or pharmacist for concerns about medication interactions with heat, appropriate medication management, and storage.

Environmental Factors and Extreme Temperatures

The risk associated with a given temperature is influenced by several environmental and individual factors. High humidity hinders the body's primary cooling mechanism by making sweat evaporation more difficult. Certain types of clothing can also impede sweat evaporation.

Reported ambient temperatures can be up to 15°C lower than temperatures experienced in direct sunlight. Prolonged exposure to temperatures around 49°C or higher is considered unsafe, with historical data indicating that temperatures exceeding 50°C have contributed to hundreds of deaths in some regions.

Even brief periods in environments above 50°C can lead to severe dehydration and strain on the heart, potentially provoking heart attacks, abnormal heart rhythms, or circulatory collapse. Heatwaves have demonstrated significant mortality risks, with one heatwave preceding Australia's 2009 Black Saturday bushfires estimated to have caused 374 excess deaths, more than twice the number of direct bushfire fatalities.