Thailand is a humid, tropical country situated near the equator. The midday sun is very intense, even if it is a cloudy day. The humidity makes everything even worse as it makes your body work even harder to stay cool. The best way to keep yourself healthy during your trip is to make sure you drink plenty of fluids. It is recommended that you drink at least 8 glasses of water a day under normal circumstances. In Thailand, you’ll probably need to drink at least 10 glass a day, especially if the climate is different from your home country. Wearing a hat and trying to stay in the shade during the hottest parts of the day will also help you lose less water.
One nice thing about Thailand is that small vendors are everywhere. You don’t have to carry lots of water with you as you can easily buy a drink when you feel thirsty at a price of 10-20 baht. Unlike some touristy places, Thais rarely charge high prices for water. The exception is when it is in a location that is difficult to reach and therefore the transportation cost of the drink is higher. This is the case on most islands and similarly remote places. If you are hiking or will be away from vendors, buy water before you leave and take it with you.
After being in the sun all day sightseeing, it’s a good idea to make sure you rehydrate yourself. Be careful of drinking too many caffeinated drinks like cola, coffee and tea as these are all diuretics and only help your body get rid of the fluid that it needs. Make sure you drink bottled water as tap water is not intended for drinking. I recommend the water that comes in clear plastic bottles that come in 500 ml – 1.5L sizes. The water in the opaque plastic bottles don’t have the same filtration standards. If it is the only thing available, it is better than drinking tap water.
If you have headaches or dizziness after being out in the sun, this can signal that you are dehydrated. Drinking plain water might not be enough at this point. I generally drink a few glasses of water and wait to see if the symptoms go away. If they don’t, I will drink an electroylte powder mixed with water. Pharmacies and most convenience stores like 7-11 should carry it. You can also buy a sport drink and get an isotonic mixture that way. However, you may also be drinking lots of sugar at the same time. Generally, if your dehydration is not severe, your symptoms should disappear. If your symptoms persist or worsen, it is time to see a doctor.