When you exercise in hot weather, start drinking 2-3 hours before your session, sip every 15-20 minutes while you train, and keep topping up afterwards. Don't wait until you feel thirsty: by the time thirst kicks in, your body is already a little behind on fluids.
Thai summer is not just about strong sun. It is humid, so sweat evaporates slowly and your body struggles to cool itself. This guide covers how much to drink, how to organise water during a session, the early signs of dehydration, and when to stop and get help.
Why you lose fluid faster in Thai heat
Working muscles produce heat, and your body gets rid of it mainly by sweating. In the hot, humid months from March to May, you sweat a lot, but the sweat does not evaporate well, so you lose plenty of water while still feeling hot.
Sweat also carries salts. If your shirt is soaked through or you notice white marks on it after training, you have lost a fair amount. Train under-hydrated and you tire sooner, your heart rate climbs at the same workload, and focus on technique slips.
Things that speed up fluid loss: training outdoors around midday, a gym with poor airflow, heavy clothing, short sleep and alcohol the night before.
How much to drink before, during and after training
These are general starting points for healthy adults. Everyone sweats differently, so adjust to how your body responds.
- Before: about 400-600 ml two to three hours beforehand, then a small glass 15-20 minutes before you start.
- During: roughly 150-250 ml every 15-20 minutes, or a few sips between sets. Sip more often on very hot days or hard sessions.
- After: rehydrate gradually over the next hour or so. A simple check is to weigh yourself before and after; most of the weight you lose is water, so drink back a little more than that, spread out.
- Sessions over an hour or very sweaty days: consider a sports drink or salty food afterwards to replace what you lost in sweat.
Drinking a large amount of plain water in a short time is not a good idea either. Aim for steady sipping. If you have a medical condition such as kidney or heart disease, or have been told to limit fluids, check with your doctor before changing how much you drink.
A quick everyday check is urine colour: pale yellow is fine; dark like tea, or much less than usual, means drink more.
A simple hydration routine for each session
Most people under-drink not because they don't know better, but because the bottle is too small, runs out halfway, or the water gets warm. Good kit solves most of that.
- Bring enough for the whole session. For about an hour of training, a litre or more is comfortable. Fill up with water and ice before you leave. The Blackube Tumbler Thermos 1200 ml keeps drinks cold for up to 12 hours and has a handle, so it sits easily next to your bench or rack.
- Match the bottle to the activity. For running, cycling or carrying in a bag all day, the Blackube Drinkmore 1000 ml has a straw and a leak-proof lid, and keeps drinks cold for up to 28 hours.
- Set drink points. In weight sessions, sip after every set. For cardio, set a 15-minute reminder.
- Dry off between sets. Keep a Fittergear Training Towel on your neck or the machine. Wipe face, hands and handles before each set; dry hands grip the bar more securely, and you leave the bench clean for the next person.
- Keep your feet dry. Sweaty feet slide in your shoes. Fittergear Training Socks COOLMAX® wick sweat and moisture away from the skin so feet stay drier on hot days.
- Refill before you leave and keep sipping on the way home.
| Model | Capacity / cold retention | Best for |
|---|---|---|
| Blackube Tumbler Thermos | 1200 ml / up to 12 h cold | Gym sessions, long workouts, keeping by your side |
| Blackube Drinkmore | 1000 ml / up to 28 h cold, straw lid | Running, cycling, carrying all day |
Common mistakes: drinking half a bottle in one go after training instead of sipping throughout; bringing a bottle that runs dry halfway; gripping the bar with sweaty hands; swapping water for coffee or very sugary drinks.
Early signs of dehydration
- Dry mouth and strong thirst
- Dark urine or peeing less than usual
- Headache, or feeling light-headed when you stand up quickly
- Unusual fatigue: the same weight suddenly feels much heavier
- Cramps in the calves or thighs
If you notice any of these, take a break, drink, and bring the intensity down.
Heat exhaustion vs heatstroke: when to stop and get help
Heat exhaustion usually shows up as heavy sweating, cool clammy skin, dizziness, nausea, weakness, headache and a fast pulse. Stop exercising straight away, move into shade or air-conditioning, lie down with your legs slightly raised, loosen clothing, cool down with a wet towel and sip water or a sports drink. If you don't feel better within about 30 minutes, or symptoms get worse, see a doctor.
Heatstroke is an emergency. Signs include a very high body temperature, confusion, slurred speech, stumbling, seizures or collapse; some people stop sweating and their skin feels hot and dry. Call 1669 in Thailand immediately. While waiting, move the person into shade, loosen clothing and cool them with water. Never give drinks to someone who is not fully conscious.
On very hot days, train with a friend or let a coach know, so someone else is watching for symptoms too.
FAQ
Is it OK to drink ice-cold water while exercising?
Yes, for healthy people. Cold water is easier to drink on hot days, and many people drink more of it. Just sip rather than gulping.
Do I need a sports drink every workout?
No. For sessions under an hour with normal sweating, water is enough. Sports drinks make sense for long, very sweaty or outdoor sessions; pick one that is not overly sweet.
Can I just drink a lot right before I start?
It's better not to. A big drink right before training can leave you bloated and running to the toilet mid-set. Spread it out over the 2-3 hours before, then top up a little.