EL Niño, the Pacific weather pattern associated with rising global temperatures, has been widely discussed in the news and on social media. It occurs when sea surface temperatures in the Pacific Ocean remain at least 0.5°C (0.9°F) above normal for several consecutive months. Scientists have forecast a 63 per cent chance that sea surface temperatures could exceed 2°C (3.6°F) later this year, creating conditions for a very strong, or “super” El Niño.

According to the World Health Organization (WHO), heat is an important environmental and occupational health hazard. As summer heat intensifies, health professionals must pay closer attention to heat-related risks.

Heat stress is a leading cause of weather-related deaths and can worsen cardiovascular disease, diabetes, mental health conditions, asthma, and other illnesses. It can also increase the risk of accidents and some infectious diseases, while heatstroke remains a medical emergency with a high fatality rate. With more people worldwide being exposed to extreme heat because of climate change, this article explores how heat affects health and how individuals can reduce their risk.

Changes in the global climate and the reality of a recent “heat dome”

Although Jamaica and the wider Caribbean are not currently experiencing what is known as a heat dome, we cannot ignore this phenomenon. I had not heard of a heat dome until recently. A heat dome is a weather phenomenon in which the atmosphere traps hot air as if covered by a lid or cap. Heat domes are influenced by factors such as sea surface temperature anomalies, including La Niña. They can develop during still, dry summer conditions when warm air builds up and high atmospheric pressure pushes it downward.

Across Europe, North America, Asia, and other regions, record-breaking heatwaves have caused thousands of heat-related illnesses and hundreds of deaths, prompting public health authorities to issue urgent heat advisories.

How heat affects your body

According to local reports, the April-June outlook from the Meteorological Service of Jamaica is expected to be less wet than usual for the second rainy period.

Hotter climates can increase the risk of dehydration, heat exhaustion, heatstroke, and worsening chronic conditions. During exercise or heat exposure, the body may store heat and raise its internal temperature. Effective cooling depends on signals between the skin, central nervous system, blood vessels, and sweat glands. Differences related to age, biological sex, illness, or injury can reduce heat loss and affect temperature control.

Temperature strongly affects biological tissues and processes. Humans normally keep deep body temperature around 36-38°C. During exercise or heat stress, it may rise to 38-40°C and still be tolerated, especially in heat-acclimatized or physically trained individuals. However, temperatures of 40-45°C can damage proteins, injure cells, and cause cell death.

Heat stress is the heat load that raises body heat storage and deep body temperature. It is influenced by metabolic heat, air temperature, radiant temperature, humidity, air movement, and clothing. Heat strain refers to the body’s response to that load, such as increased body temperature or heart rate.

Heat and medicines

According to the US Centers for Disease Control, heat can interact with medications and cause serious side effects. Clinicians, patients, and pharmacists should recognise medicines that raise heat-related illness risk, understand these interactions, and plan medication use for hot days.

People living with diabetes, hypertension, kidney disease, asthma, heart disease, and other chronic illnesses should take extra precautions during periods of extreme heat.

Heat exposure may damage medication delivery devices or degrade medications. Inhalers, for example, can burst in hot environments, such as car trunks on hot days. EpiPens may malfunction or deliver less epinephrine when exposed to heat. Insulin, which should be refrigerated, may become less effective if left in the heat for prolonged periods.

Some medications can increase skin sensitivity to the sun. Antifungal medications such as flucytosine, griseofulvin, and voriconazole, as well as antibiotics such as metronidazole, tetracyclines, and fluoroquinolones, can increase sun sensitivity and cause a sunburn-like rash. Patients taking these medications should avoid excessive sun exposure, wear protective clothing and hats, and use broad-spectrum sunscreen that protects against UVA and UVB rays with an SPF of 30 or higher.

Practical self-care tips from your pharmacist

Health Canada (2024) advises pharmacy professionals to help patients prepare for heat waves by recognising heat illness symptoms and supporting high-risk groups, including older adults, infants, pregnant individuals, athletes, people with chronic conditions, and those taking medicines that affect temperature regulation.

*Staying well hydrated is essential. Prevent heat illness by drinking water regularly, even before feeling thirsty, especially if you are older, active, or taking medicines that increase urination. Limit alcohol, sugary drinks, and excess caffeine, which may worsen dehydration.

*Outdoor Activities — Plan outdoor activities for cooler morning or late afternoon hours. Avoid direct sun from 10:00 am to 4:00 pm; wear loose, lightweight clothing, SPF 30+ sunscreen, a wide-brimmed hat, and seek shade. Reduce strenuous activity and mist the skin with cool water to cool down when hot.

*Warning signs of heat-related illness — Do not ignore persistent thirst, dizziness, headache, cramps, nausea, fatigue, rapid heartbeat, confusion, or fainting. For heat exhaustion, move to a cool place, loosen clothing, drink cool water if conscious, and rest. Seek emergency care for confusion, seizures, unconsciousness, or feeling very hot without sweating, as these may signal heatstroke.

Medication safety during hot weather

Do not stop prescribed medicines because of heat unless instructed by a physician. Pharmacists can review medicines, identify heat-related risks, advise on hydration, and recommend monitoring.

People with hypertension should monitor blood pressure, and those with diabetes should check blood glucose more often because dehydration can affect control. Store inhalers safely and avoid hot spaces where pressure can build.

Finally, as temperatures rise, heat protection is becoming part of everyday health care. Most heat-related illnesses can be prevented by staying hydrated, avoiding excessive sun, recognising warning signs, and using medicines safely. This summer, speak with your pharmacist to help keep yourself and your family safe in a changing climate.

Tieca Harris Kidd is a senior lecturer and registered pharmacist, School of Pharmacy, College of Health Sciences, University of Technology, Jamaica.

Tieca Harris Kidd