A dozen people died of dehydration and heat exhaustion in Indonesia this week while stuck in a 21-km traffic jam caused by road-works. Except for one toddler who was poisoned by exhaust fumes, most people who died of severe dehydration were older people travelling home to celebrate Eid ul-Fitr. The combination of daytime temperature of around 30°C in the city of Brebes, where the jam occurred, combined with high humidity caused the deaths.
To many living in India where summer temperatures routinely cross 40°C for months on end, the news of people collapsing on exposure to temperature as low as 30°C may appear puzzling, but they need to take into account the high humidity that causes the body to rapidly lose water and the advancing age of the victims, almost all of whom would have been fasting during the holy month of Ramadan.
Babies, children, people over 60 years, those who are on restricted diets, fasting or ill need more water than healthy people. While babies and children are more susceptible to dehydration because of their smaller body weights, people who are fasting and on specialised diets develop electrolyte imbalances that make their bodies lose water faster. People who are ill are also at higher risk as there fluid needs are greater, more so if the illness involves fever, vomiting, or diarrhoea.
How much do I need?
On average, water accounts for 60% of bodyweight. Apart from keeping the brain sharp, it moistens tissues, cushions the joints, regulates body temperature and helps the body absorb nutrients and flush out toxins. The US Institute of Health recommends a daily fluid intake of about three litres (12 glasses) for men and 2.2 litres (11 glasses) for women. These values represent adequate intake levels, those who are very active physically or who live in hot climates need more. About 80% of the total water consumption comes from drinking water and beverages -- including caffeinated drinks such as tea, coffee and colas -- and rest comes from food, such as fluid found naturally in fruits and vegetables, juices, milk and yoghurt.
Beating the heat
The human body takes four to seven days to acclimatise to the high temperature, so you need to be hydrated in the first few days of hot, sticky weather. At most risk are children under 10 years, people over 65 years old, people on restricted diets, alcoholics, people on anti-psychotic drugs, diuretics, or those who live or work in poorly-ventilated spaces.
How can you tell if you are having enough water? If you feel hot, drink a glass of water every hour to replace body fluid lost through sweating. Though you see no visible sweat in air-conditioning or dry weather, both conditions are extremely dehydrating, so you must let thirst be your guide. Apart from that, telltale dehydration signs are dry and scaly skin, muscle cramps and frequent constipation. Acute dehydration lowers blood pressure, raises heart rate, makes the eyes appear sunken, and causes lethargy and confusion.
Heat-related illnesses take many forms, ranging from painful cramps to potentially-fatal heat stroke. Heat cramps are sharp, sudden muscle spasms caused by electrolyte imbalance through sweating from physically activity in hot weather. Usually, the cramps affects muscles in the thigh and calves (quadriceps, hamstrings, gastrocnemius), core (abdominal wall and back), and upper arms (biceps and triceps). Salt and water replacement stops pain.
Heat exhaustion is a less severe form of hyperthermia, with symptoms of profuse sweating, anxiety, fatigue, dizziness, clammy skin, gooseflesh and vomiting. It occurs because the body cannot cool itself and if untreated, progresses to heat stroke very quickly if the lost water is not replaced and the body temperature brought down very quickly.
Heat stroke causes symptoms of hot and dry skin, rapid pulse rate, flaccid muscles, with headache, dizziness, abdominal pain and disorientation. In rare cases, a person may go into shock with diffuse bleeding, liver damage and renal failure, which cause death. Heat stroke is a medical emergency that needs hospitalisation.
There are times when you should not wait for signs of thirst before replenishing water, such as when the weather is hot and sweaty, when you’re doing strenuous activity outdoors, or are down with an illness. In such cases, the rule of the thumb is to replace the water lost as soon as possible, which means drinking a glass or two before stepping out in the heat, and again, a glass or two at the end of the activity.