Record high temperatures above 50oC in parts of the USA, sweltering days above 40oC on the courts of Wimbledon, and heatwave conditions in parts of Europe last week are a reminder to Australians heading to northern hemisphere countries to prepare for the heat – right from the moment they arrive, Travelvax Australia advises.
"Escaping the southern winter may mean having to suddenly cope with heat that can be debilitating – even dangerous," said Dr Eddy Bajrovic, the Medical Director of Travelvax Australia.
"Even for fit, young adults it can be very uncomfortable stepping from an air conditioned plane into 40oC-plus temperatures on the airport tarmac during the middle of the day.
"But, young children and the elderly can't respond as quickly to high temperatures and can become dehydrated very rapidly.
Heat can trigger medical emergencies
"Very high body temperatures may damage the brain or other vital organs. But, it can also make the blood thicker and increase cardiac output.
"These reactions to heat can overload the heart and lead to a heart attack or stroke, particularly in travellers with an existing heart condition."
People with chronic medical conditions, such as diabetes, should also plan for high temperatures. Diabetes makes it harder to handle high heat and humidity, and may require diabetic travellers to adjust their medication, as well as their diet and fluid intake.
Heat stress is often worse in high humidity: Sweat doesn't evaporate as quickly as normal and heat is trapped in our bodies. Other factors that influence how quickly a person can cool off include age, obesity, fever, dehydration, heart disease, mental illness, poor circulation, sunburn, and prescription drug or alcohol use.
Begin preparing for the heat during your flight
To prepare for the heat on arrival, travellers should maintain adequate fluid intake during the flight, in the airport terminal, and while travelling to their accommodation, Dr Bajrovic said.
In-flight drinks containing alcohol will actually cause you to lose more fluid and should be avoided or kept to a minimum.
In a hot climate, an adult needs to drink about 3 litres of water a day, and at least 5 litres if undertaking a strenuous physical activity.
Children should simply be encouraged to maintain a sustained intake of fluid: for infants and toddlers breast milk, formula, or water is appropriate; water for older children. Older kids participating in strenuous activities can consume sports drinks to help replace sodium and other elements lost through perspiration, and they should be encouraged to drink even if not yet thirsty.
Treating heat exhaustion and heat stroke
Heat-related illness occurs when our body's temperature control system is overloaded. High temperatures can cause physical symptoms ranging from muscle cramps, tiredness, nausea, and vomiting, through to an altered mental state.
There are two stages to heat stress - heat exhaustion and heat stroke.
HEAT EXHAUSTION – Heat exhaustion is a milder form of heat-related illness. It can develop after several days of exposure to high temperatures and inadequate or unbalanced fluid replacement. The elderly, people with high blood pressure, and those working or exercising in high temperatures are prone to heat exhaustion. The warning signs include heavy sweating, paleness, muscle cramps, tiredness, weakness, dizziness, headache, nausea or vomiting, and fainting.
Heat cramps are muscle pains or spasms – usually in the abdomen, arms, or legs – that may result from heavy sweating due to strenuous activity. Sweating depletes the body's salt and moisture, causing painful cramps. Heat cramps may also be a symptom of heat stroke (see below). Travellers with a heart condition and those on a low-sodium diet should seek medical attention for heat cramps.
WHAT TO DO – The key to treating heat exhaustion is rehydration and rest. Initially, try to lower the effected person's temperature by getting them to a cool space, such as an air-conditioned room or a car. Start with sips of cool to cold water and gradually increase intake. For adults aim for 250mls every 15 minutes. Between 2 and 3 litres of fluid over 2-3 hours may be required to complete the rehydration process.
CHILDREN: Lay the child in a cool place, with clothing removed. Cool the child by fanning them and placing moist, cool cloths on their forehead and wrists. Cramps can be treated by applying ice packs and gently stretching (but not massaging) the muscles. Replace lost fluids with regular sips of water (ideally with some added sugar) and seek medical aid if the child does not recover promptly.
HEAT STROKE – The next stage of heat exhaustion is heat stroke. Heat stroke is a medical emergency. The warning signs can vary, but generally they include at least some of the following: extremely high body temperature (above 39oC); red, hot, and dry skin (an absence of sweating); irritability, hallucinations, dizziness, and nausea; unsteadiness in walking; and, changes in the person's level of consciousness.
WHAT TO DO – Have someone call for immediate medical assistance while you begin treatment by:
- Getting the victim into shade.
- Cooling them down as quickly as possible by placing them under a cool shower, spraying them with water from a garden hose; sponge them with cool water; or wrapping them in a cool, wet sheet and fanning them.
- Monitoring their body temperature until it is below 38-39oC.
- Giving them cool water or other non-alcoholic drinks. Heat stroke victims should NOT drink alcohol.
- Following up to ensure medical assistance arrives as soon as possible.
CHILDREN: Initially, treat a child as for heat exhaustion and seek urgent medical attention. Heat stroke puts enormous stresses on the body's circulation and requires expert, rapid treatment by a medical professional.
Preventing heat-related injuries during your stay
Get a head's up on the weather
Check the short- and medium-term forecast for your destination a day or two before you leave. Save the link into your phone so you can continue to check for changing conditions – especially rising temperatures – during your stay.
Take time to acclimatise
It can take time to adjust to the higher temperatures in a hot, humid country – especially for kids, the elderly, and people who are overweight. Give all members of the family to gradually increase the length of time and intensity of exercise before tackling the full holiday schedule. A 20-minute walk or other light to moderate exercise in the cooler part of the day on the first and second day will help everyone to acclimatise.
When humidity's high, head for the shade
The heat index (HI) combines air temperature and relative humidity: The higher the humidity, the less efficient perspiration becomes and the more heat remains in the body. Listen out for the HI 'factor' in summertime weather reports on the local media. If the HI is high, stay indoors as much as possible. Air-conditioning is the number one protection against extreme heat. Look for relief in shopping malls, public libraries and other air-conditioned locations. If you must be outdoors, look for a cool place to rest during the hottest hours of the day.
Drink lots of fluids (not alcohol!)
Most people begin to feel thirsty when they've already lost a litre of fluid through dehydration. That's why it's important to drink plenty of fluids – even before your body begins telling you that you're thirsty. Water or other non-alcoholic fluids produce perspiration to keep your body cool and your brain and other vital organs functioning normally. (As mentioned, alcohol is counter-productive as it results in fluid loss). Drink from sealed, bottles and ensure you have a supply at all times, maintaining a constant intake of up to 1 litre an hour if you are exercising or walking in the heat. Passing light yellow urine several times a day is the best indicator of adequate hydration. (About sports drinks... Popular with athletes, sports drinks replace sodium, chloride and other elements lost through perspiration. They are suitable for older children and adults. But, it should be remembered that they can actually slow water absorption and should be consumed in moderation along with water – not instead of it. For younger children, dilute sports drinks with four parts water.)
Dress for the heat
When it comes to dressing for heatwave conditions, choose lightweight, light-coloured, and loose-fitting clothing. Cotton absorbs perspiration and 'breathes' better than most synthetic materials, which helps to cool your body. A wide-brimmed hat will provide shade and keep the head cool. If heading outdoors, apply a sunscreen 30 minutes prior to going out and continue to reapply as necessary. (NB – Sunburn reduces your body's ability to cool itself and can result in a loss of body fluids, not to mention the short-term pain and long-term skin damage.)
Finally, NEVER, EVER leave kids alone in a car
A car can heat up from 27oC to 49°C in just 15 minutes. Tragically, every summer children and pets die or are permanently injured after being left in the family car.
Read more about heat stress and how to avoid it from Travelvax Australia and the US CDC.
For more expert advice about coping with the heat, possible vaccinations and other travel health-related issues for your next overseas trip, please call Travelvax Australia's advisory service on 1300 360 164 (toll-free from landlines). You can also book a medical appointment at one of our 32 clinics around Australia.