Every living creature needs water to survive. Yet sweating, peeing, vomiting, or having diarrhea can cause a loss of water, further increasing your liquid needs, in a complex physiological process making you feel thirsty.
If you’re thirsty, that’s the clearest sign you’re dehydrated, which means your body doesn’t have enough water to function properly.
Being dehydrated doesn’t just mean your body is losing water it also means you're losing salt and potassium, which help your body breathe, move, and do all the other things it needs to do to stay up and running.
Specific health diseases, including diabetes, can put you at an increased risk for dehydration. If you’ve been sweating too much due to heat or overexertion, throwing up or having diarrhea because of the flu or another serious illness, or urinating frequently, it’s important to watch your fluid intake.
People who are particularly vulnerable to losing water include those who are unable to satisfy their thirst because of disease, those who are athletes, and those who are just too young or too old to replace water on their own. Men who are middle-aged or elderly may also be at an increased risk of difficulties from dehydration.
The researchers found that over time, the body becomes worse at identifying markers of dehydration (such as high levels of salt in the blood), and without these signals, older adults may not understand they are dehydrated or take steps to rehydrate. Untreated dehydration can cause the heart rate to increase.
Becoming extremely dehydrated as losing more than 10 percent of your body weight in fluid can lead to injury or fatal difficulties, and it requires an ER visit. Seizures, cardiac arrhythmia, or hypovolemic shock can occur because your blood volume is too low.
Yet it seldom comes to that.
Most of the time, you can easily replace your water stores and resist dehydration. The truth is you can lose 3 to 4 percent of your body weight through dehydration without feeling any real signs. Yet, once you have lost 5 to 6 percent, you’ll start to feel the symptoms of dehydration. Thirst, fatigue, dizziness, or constipation are sure clues it’s time to reach for water or a sports drink that’s low in sugar and high in electrolytes.