This article was previously published on March 29, 2018 and has been updated with new information.
Have you ever been so busy that you didn’t want to drink even a sip of water for a long time, then suddenly realized that you were extremely thirsty and needed a long drink? By replenishing your body with water when it tells you you’re thirsty, you can often prevent dehydration. In fact, the body’s physiological thirst mechanism is often activated before you become dehydrated, giving you a chance to rehydrate before it’s too late.
However, there are exceptions to this rule, with the elderly and young children at particular risk of dehydration. It is estimated that 20% to 30% of older adults are dehydrated,first It is usually due to a lack of water and the fact that people naturally have lower amounts of water in their bodies as they age.2 Babies and children can also quickly become dehydrated, especially if they are sick and have vomiting or diarrhea.
One study even found that more than half of American children are dehydrated, while about a quarter do not drink water on a daily basis.3 Among healthy adults, the US National Academy of Sciences concludes, “The majority of healthy individuals adequately meet their daily hydration needs by letting thirst be their guide. .”4
However, if you ignore your thirst or find yourself not drinking enough water in hot weather, especially when you’re exercising, it’s very easy to become mild to moderate dehydration, with The signs and symptoms may surprise you.
Why does your body need water?
Your body contains about 42 liters (44.4 liters) of water, which makes up 50% to 70% of your body weight. Your blood is 85% water, your muscles are 80% water, your brain is 75% water and even your bones are 25% water,5 This signals the importance of this liquid to your health. So what happens if you don’t drink enough?
The number 1 risk factor for kidney stones is not drinking enough water, in the first place. There is also some research showing that high fluid intake is associated with a reduced risk of certain types of cancer, such as bladder and colorectal.6 Even the risk of fatal coronary heart disease is related to water intake, with one study showing that women who drank 5 or more cups of water a day had a 41% lower risk compared with those who did not. Women drink less. Meanwhile, men reduced the risk of disease by 54%.7
Your body also needs water for blood circulation, metabolism, body temperature regulation, and waste removal. If you are dehydrated, even mildly, your mood and cognitive function can also be affected. In a study of 25 women, those who were 1.36% dehydrated had worse moods, irritability, headaches and poor concentration, and found tasks more difficult.8
When you don’t drink enough water, you can also put yourself in danger on the road, according to a study published in the journal Physiology & Behavior, showing that dehydrated drivers make twice as many mistakes over time. drive two hours compared to when drinking enough water. drivers.9
How your body reacts to too little water
Your body functions optimally when well-hydrated, while negative biological changes occur when fluid is lacking. When you’re dehydrated, brain tissue fluid decreases,ten lead to changes in brain volume. Dehydration also affects your heart. In a March 2022 study, researchers found that staying well hydrated throughout your life “may slow the decline in heart function” and even reduce rates of heart failure.11
Your blood also becomes thicker and circulates less, which can lead to muscle cramps and also trigger your kidneys to retain water, so your urine output decreases. Furthermore, according to Toby Mündel, senior lecturer in exercise science, Massey University, New Zealand:twelfth
“The denser and more concentrated your blood is, the harder it is for your cardiovascular system to compensate by increasing your heart rate to maintain blood pressure. When your dehydrated body is ‘pushed’ – for example, during exercise exercising or dealing with heat stress – increased risk of burnout or breakdown, which can cause you to pass out, for example when you stand up too quickly.
Less water also interferes with the body’s efforts to regulate temperature, which can cause hyperthermia (body temperature much higher than normal). At the cellular level, ‘shrinkage’ occurs when water is effectively borrowed to maintain other reserves, such as blood. The brain senses this and causes increased thirst. “
Mündel recommends tracking your body weight to keep an eye on your hydration levels. First thing in the morning when you get out of bed, weigh yourself three mornings in a row, then average your weight. This is your normal baseline weight and you should stay within 1% of that level if you’re well-hydrated (assuming other factors don’t affect your weight).
Surprising signs of dehydration
When your body is dehydrated, dehydration can manifest with surprising signs and symptoms, including:13
• Halitosis – Saliva is antibacterial, but when you’re dehydrated, you reduce the amount of saliva in your mouth. This allows odor-causing bacteria to multiply.
• Sugar cravings – Thirst can disguise hunger, and many people turn to a snack when they’re really thirsty. Sugar cravings are especially common when you’re dehydrated because your liver, which releases stored glucose, needs water to do so.
Furthermore, Amy Goodson, sports nutritionist for the Dallas Cowboys, tells Health, “When you exercise in a state of dehydration, you use glycogen (stored carbohydrates) at a faster rate, thereby reduce your reserves faster.”14
• Sports decline – According to Goodson, if you’re in the process of training, a 2% loss of body weight due to dehydration can lead to a performance loss of up to 10%.
• Reduced alertness and increased fatigue – In a 2013 study, 20 healthy women in their 20s didn’t drink all of their drinks for 24 hours. While no clinical abnormalities were observed in biological parameters (urine, blood, and saliva), thirst and heart rate increased and urine output sharply decreased (and became darker).
As for the mood effects, the authors note, “The significant effects of [fluid deprivation] on mood including decreased alertness and increased sleepiness, fatigue, and confusion. “15 Other research has shown that even 1% dehydration can adversely affect cognitive performance.16
• Chills – If you feel chills for no reason, it could be because you need to drink water. When you’re dehydrated, your body restricts blood flow to your skin, which can make you feel cold.
Constipation is another consequence of not drinking enough water, as your body will actually draw water from the stool to make up for what you didn’t absorb. This makes your stools drier, harder, and harder to pass. Other symptoms of mild and severe dehydration include:17
| Mild to moderate dehydration | Severe dehydration |
|---|---|
| Dry, sticky mouth | Extreme longing |
| Drowsiness or fatigue | Irritability and confusion |
| Dry skin | Sunken eyes |
| Headache | Dry skin doesn’t heal when you pinch it |
| Feeling lightheaded | Low blood pressure |
| Dizzy | Arrhythmic heartbeat |
| Little or no tears when crying | Breathe fast |
| Minimal urine | There are no tears when crying |
| Dry, cool skin | Fever |
| Muscle cramps | Urinating little or no urine and any urine color darker than usual |
| In severe cases, delirium or unconsciousness |
How much water is enough?
There is quite a bit of debate about how much water the average person needs to stay healthy. You may have heard the recommendation to drink 8 8-ounce glasses (referred to as “8×8)” of water a day to stay healthy, and it’s often taken for granted as scientific fact. It’s not quite that simple, however, as many factors affect how much water you need, from your age and health status to your activity level and climate.
Furthermore, in a review published in the American Journal of Physiology, Dr Heinz Valtin of Dartmouth Medical School, could find no scientific basis for the aptly described 8×8 rule. rather than a legend.18 Valtin also suggests some myths about water consumption, such as waiting to drink until you are thirsty is too late, because you are already dehydrated.
As Valtin said, “[T]Hirst is so sensitive, quick, and precise that it’s hard to imagine that evolutionary development would leave us chronically dehydrated that must be compensated for by forced-drinking fluids. “19 Finally, you don’t have to try to figure out exactly how much water your body needs or keep track of how many glasses you drink in a day.
It doesn’t have to be because your body will tell you. Simply using thirst as a guide to how much water you need to drink is a simple way to help ensure your individual needs are met on a daily basis. You can also use the color of your urine as a guide. If it’s a deep, dark yellow, it’s likely that you’re not drinking enough water. Pale straw or pale yellow is usually a sign of enough water in the body.
If your urine is small or if you haven’t urinated for many hours, it is also a sign that you are not drinking enough. (Based on results from a few different studies, a healthy person urinates on average about seven or eight times a day.)
If you know you have a tendency to ignore your thirst and not drink when your body shows this sign, then you should pay more attention and always take the time to drink some water when thirsty. In infants and children, detecting dehydration can be more complicated, but if you see these symptoms, you can assume your baby is dehydrated and should seek medical attention right away:
|
The soft indentation (font) on their head |
Little or no tears when they cry |
|
Dry mouth |
Some wet diapers |
|
Sleepy |
Breathe fast |
