The purpose of consuming liquids is to mitigate dehydration. Hydration is the addition of one or more water molecules water to other molecules. Water molecules are highly polar. As such, they are attracted to other polar molecules, including other molecules of water.
Really dehydrated people wouldn’t have enough fluid to circulate properly, so often have a low blood pressure, resulting in organs specially the kidneys not getting enough blood so develop an acute kidney failure, pee just very small amounts of urine, feel a lot of thirst, and if left untreated could die because of that.
Muscles are like an engine- they consume calories to perform work, but also lose some energy as waste heat. The ability of the body to exchange that heat with the outside environment requires there be a temperature differential to allow differences in humidity and net evaporation to keep you cool. Too hot, and you overheat.hydration science during the cycling
One of the consequences of overheating is sweat. Under ideal circumstances, where the air is cool and dry, sweat will evaporate and remove heat, allowing optimal performance. Lose a lot of fluid to sweat, and the volume of water available to the blood goes down. Lose 5% of your body mass in water through sweat with no other compensation, and you could lose 25% of your blood volume. Yes, that's kind of like losing 3 pints of blood. The term for extremes of this condition is called hypovolemia. But dehydration is not just one variable- it's three (with both the electrolytes sodium and potassium and water potentially affected). While you can be hypotonic (losing net electrolytes) or hypertonic (net losing water), your body will attempt to maintain a balance and you will lose an equal ratio of both (isotonic dehydration).
Reasonably diluted solutions of electrolytes, sugars, and amino acids maximize the transfer of fluid from mouth to blood. Too high, and the body feels the need to dilute them first and may cause an initial increase in dehydration, and too low and you won't trigger the transport mechanisms of the small intestine. Therefore, cyclists should drink water from time to time during the cycling before they feel thirsty.hydration science during the cycling
After the cyclists drink the water, it takes minutes to over one hour for the water to hydrate their body. In fact, if so-called "bound" water was unavailable, it would imply that water absorption happens poorly from foods or beverages like milk, which is not true: a person on the right diet could, (theoretically) get all of their water entirely from foods, without having to consume extra liquid, provided the food contains sufficient replacement water. People tend to forget that food contains water and on average, people get about 20% of their water from food. Remember, clean drinking water is a first world luxury, and it is unwise to drink any old source of water particularly if there's a chance of cholera contamination. Outside of the first world, water is most commonly obtained from foods, soups, teas, beer, fruit juices, etc, not a bottle of hypermarketed alkaline snake oil. After supplement the water your body needs to encourage itself to consume, you're good to cycle further.