OH TO AESTIVATE
BY Dr. Sanjiva Wijesinha
I can still remember our high school zoology teacher teaching us a new word – ‘aestivate.’ He told us that “when the ‘big match’ season comes around in March each year, the weather is so hot in Colombo that even the snails go to sleep.”
He went on to explain that the concept of going to sleep is called ‘aestivation’ – being derived from the Latin word aestas (meaning ‘summer’). It’s similar to the hibernation that animals in cold climates undergo when winter comes around, going into a state of dormancy or torpor, staying still and surviving on their food stores rather than moving around actively in search of fresh provender.
As we approach the ides of March each year, I recall this story about the snails going to sleep and remind myself to take appropriate precautions to stay healthy during the hottest months of the year.
The month of March in Sri Lanka is predominantly dry with temperatures rising to the mid-300C range. Having the longest number of daylight hours (nine on average), there’s plenty of time in March for the land and its people to heat up.
So what can we do to avoid the discomfort and unhealthy effects of such high temperatures?
Spending time outside in the heat causes the body’s core temperature to rise and stimulates it to sweat. When this perspiration collects on our skin, it evaporates and draws heat from the surface and cools the body.
In extreme heat however, we perspire so much that there isn’t enough time for the sweat to evaporate. If the humidity is very high, it prevents evaporation – and this leads to more and more sweating.
In fact, the body loses so much fluid that it gets dehydrated. With the loss of all this fluid, you start to get thirsty, which is the sign to replace the lost fluid and chemicals that are eliminated in your sweat. If not adequately replaced, symptoms like exhaustion, tiredness and muscle cramps may develop. Therefore, it is most important to wear the right clothing – light-coloured (to reflect rather than absorb the sun’s rays), lightweight and loose enough, to allow air to flow between fabric and skin so that sweat evaporates.
Spending time in the shade rather than under the sun’s heat is sensible.
Foreigners visiting for the first time are amazed to see Sri Lankans carrying umbrellas to protect themselves not from the rain but solar rays! But if they spend long enough in the heat of our land, they’ll soon realise the value of protecting themselves from the energy sapping sun.
It stands to reason that you must replace the fluid your body is losing so drink plenty of water. Replacing the minerals you lose in sweat with salt or salty foods is also a good idea. Although the body naturally does a good job of keeping you cool, it needs the raw materials to do its job.
You know there’s sufficient fluid in the system if the urine you pass is clear. The standard advice is to drink as much water as one needs to pass clear urine at least three times a day. And even though you may enjoy a cold beer on a hot and humid day, keep in mind that alcohol stimulates the kidneys to produce urine – so instead of rehydrating, it dehydrates you!