Just 1-2% dehydration starts to affect you.
Compared to being fully hydrated, just 1-2% dehydration starts to affect not only your physical body but also your ability to think. Physically, you will experience effects such as reduced endurance during exercise, less effort exerted during physical tasks such as exercise or manual labour, higher ratings of fatigue, and experiencing headaches. These might seem logical, but the effects on cognitive functioning are much more interesting. Mood changes such as tension and anxiety occur, energy levels drop- even during sedentary activities, and the ability to concentrate or remember things is impaired as well.
You can’t rely on thirst to tell you when you are thirsty
If you are feeling thirsty, you are already past the 1-2% dehydration point, as our body doesn’t receive the signal to drink more water until we have reached a mildly dehydrated status. Going by the amount of water you’ve had to drink that day isn’t going to be an accurate way to tell if you are hydrated enough either, as you can lose around a litre of body fluid through sweat per hour during physical activity, you will lose more water on hot days, and you may not make much progress improving your hydration status with an average amount of water if you start the day off already dehydrated. The easiest way to tell how your hydration status is looking is to check the colour of your urine- dark urine is a sign of dehydration, your urine should be either a pale yellow or clear.
8 glasses of water a day isn’t right
To say that a 50kg female would need the same amount of water as a 100kg male doesn’t make much sense does it? Each person will have varying requirements for water depending on weight, activity levels, environment, muscle mass, whether pregnant or breastfeeding, and health factors etc. In general people need around 35ml/kg body weight a day- roughly a litre a day can come through food eaten, and the rest needs to be through fluids, and anything containing caffeine such as tea, coffee, energy drinks etc. will cause increased urine output so aren’t great options if you are trying to improve your hydration status. Of course, water is the perfect fluid as there aren’t any extra hidden calories, or salt or sugar, so start carrying around that water bottle with you and pay a little more attention during your bathroom trips so see if you need to up your intake.