Understanding Hot Spells: Health Risks & How to Stay Safe

In recent years, extreme heat and heatwaves have become increasingly frequent and intense across many regions. According to the World Health Organization (WHO), extreme heat is one of the world’s deadliest natural hazards, responsible for hundreds of thousands of heat-related deaths every year. For travelers, outdoor workers, and anyone living in tropical climates, understanding how hot spells affect your health is essential.

In Indonesia, the Meteorology, Climatology, and Geophysics Agency (BMKG) reports that the regions most affected by current high-temperature conditions include Nusa Tenggara, Java, Kalimantan (West and Central), Sulawesi (South and Southeast), and parts of Papua.

This phenomenon is caused by the apparent motion of the sun combined with the Australian monsoon effect. The extreme heat is expected to persist until late October or early November 2025. However, if rainfall remains uneven across Java, these hot weather conditions could extend well into November.

A hot spell is defined as a sustained period of unusually high temperatures for a given region, often accompanied by high humidity, little wind, or intense sunlight. These conditions can overwhelm the body’s ability to cool itself. Even temperatures considered tolerable can become dangerous when the body is exposed for long durations or during physical exertion. The National Weather Service notes that prolonged time or physical activity outdoors with a heat index of 95ºF (35ºC) or higher could cause fatigue and warrants caution.

When the body cannot dissipate internal heat effectively, a range of health issues can occur:

• Dehydration – Excessive sweating and fluid loss.
• Heat exhaustion – Symptoms like heavy sweating, weakness, dizziness, nausea.
• Heat stroke – A medical emergency: high body temperature, confusion, fainting, potentially organ damage.
• Exacerbation of chronic conditions – High heat can worsen cardiovascular disease, respiratory problems, kidney disease, diabetes.
• Mental health & cognitive effects – Heat stress can reduce cognitive performance, affect mood, and aggravate mental health conditions

Symptoms of heat-related illnesses depend on the type and severity of the illness.

Some common symptoms of heat exhaustion include:

• sweating heavily
• exhaustion or fatigue
• dizziness or lightheadedness
• blacking out or feeling dizzy when standing up
• weak but fast pulse
• nausea
• vomiting

Symptoms of heatstroke include:

• discolored skin that feels hot to the touch
• strong and fast pulse
• losing consciousness
• internal body temperature of 104ºF (40ºC)
•  or higher

Some groups are at higher risk during hot spells:

• Older adults and very young children (thermoregulation less efficient).
• People with chronic illnesses (heart, lung, kidney, etc).
• Outdoor workers or those exposed to heat for long periods. 
• People on medications that affect heat regulation or cause fluid/electrolyte imbalance.

Here are steps you can take to protect your health when temperatures soar:

• Stay hydrated – Drink plenty of water even if you’re not visibly sweating. Avoid excessive alcohol or caffeine.
  
• Stay cool – Use air-conditioning or fans, take cool showers, avoid being in direct sun during peak hours.
  
• Limit outdoor activity – Especially during the hottest parts of the day; schedule strenuous work early morning or evening.
  
• Wear appropriate clothing – Lightweight, loose, light-coloured clothes; hats; UV protection.
  
• Monitor vulnerable individuals – Check on older family members, children, or those with health issues.
  
• Recognize early warning signs – Dizziness, rapid heartbeat, extreme thirst, confusion—seek medical help if these occur.

With climate change, hot spells are increasing in frequency, duration and intensity, posing a growing public-health challenge. As health professionals and individuals, being prepared is essential.

Hot spells are not simply uncomfortable. They can pose serious risks to health when overlooked. By understanding how extreme heat affects the body, knowing who is most at risk, and taking practical precautions, you can stay safe and healthy even when the thermometer climbs. In any case of heat-related illness, especially signs of heat stroke or severe dehydration. Seek medical care without delay.

📞 Contact Bali Medical Service anytime for reliable health support while traveling in Bali.