How much do I need to drink?
Fluid needs are individual and of course depend on how much you sweat.
Insufficient fluid intake leads to poorer physical performance but also affects us us mentally, for example reduced decision-making ability, longer reaction time and reduced concentration. If we have too little, we can become nauseous, feel extremely tired, have headaches and muscle cramps.
If the exercise lasts no more than an hour, fluid intake is not so important. Choose if and how much you want to drink based on what feels best for you.
But we usually cycle for more than an hour. And then the following benchmark applies:
0,15-0,25 ml per kg body weight and min
Fluid balance clearly affects performance
So if you weigh 80 kg, that's 12-20 ml per minute.
In 1 hour, 60 minutes, this becomes: 720- 1200 ml per hour.
As you can see, it's a pretty wide range. These recommendations are based on studies where it has been 20-33 degrees, so for colder conditions the need can certainly be less (provided you don't wear too much clothing and sweat a lot because of it).
If you want to get to the bottom of how much you're sweating and whether you're getting enough, there's an easy way to measure it. Weigh yourself right before you go on your exercise and then weigh yourself right after you come back (wearing the same amount of clothes). A weight loss of up to 2% is considered ok, but a larger weight loss can impair performance. If you weigh 80 kg before training and 78.4 kg after training, you have lost 2% of your body weight. If you want to be really accurate, make sure you have peed before weighing yourself, on both occasions. I'm not saying you should do this every time but it might be interesting to do under different types of sessions and conditions to learn how much fluid you are losing.
Many people do not drink the recommended amount but go by their feelings and drink when they are thirsty. What is your approach?
If we go by our feelings of thirst, we usually drink less than our measured needs. It's not entirely clear from studies how much it affects performance whether you drink by instinct or measured need. Other factors affect performance and fluid balance, such as how hot it is, how much you sweat, how much you consume, how much fluid you drank before, how your stomach tolerates fluid, etc.
To find out what works best for your body, I encourage you to test different amounts under different conditions. Just because you're doing one way now doesn't mean it's best - does it? If you try doing things differently, you'll have something to compare with, and learn from 😊