Water makes up over two-thirds of the human body. It plays an important role in lubricating the joints and eyes, as well as aiding digestion, flushing out toxins and waste and keeping skin healthy. There’s something else it does: it keeps you happy.
When your hydration levels dip, so does your mood. That’s because when the normal water content of the body is reduced, it upsets the balance of minerals, like salts and sugars, in the body, which affects the way it functions.
Dehydration happens when you use or lose more fluid than you take in, and your body doesn’t have enough water to carry out its normal functions. Without replacing lost fluids, dehydration can occur.
How does this affect your brain?
Extreme dehydration, which happens after days of reduced fluid intake, causes significantly reduced cognitive function, delirium unconsciousness, coma, and may ultimately lead to death.
Symptoms of dehydration
The signs and symptoms of dehydration differ between individuals and range from minor to severe.
Mild to moderate dehydration may include the following:
- Feeling tired or sleepy
- Decreased urine production
- Headache
- Dizziness
Symptoms of severe dehydration include:
- Blood pressure drops when you try to stand up after lying down
- Racing heart rate
- Fever
- Poor skin elasticity (skin slowly sinks back to its normal position when pinched)
- Lethargy and confusion
- Seizure
- Shock
Prevent getting dehydrated: drink according to thirst
Severe dehydration is uncommon and usually occurs only in athletes participating in extreme events (e.g. desert marathon runs) or in other unusual circumstances.
There is no one-size-fits-all “right” amount of water to drink each day. The exact amount you need is extremely variable and depends on a person’s body size, physical activity levels, climate and what types of food they are eating. The best way to get in the right amount of fluid each day is to “drink to thirst”. Your kidneys work to perfectly balance and regulate your water requirements so that you take in and retain only as much fluid as you need. What’s more, fluid intake can also come from food – in fact, around as much as 25% of your water intake comes from what you eat, not what you drink.
Exceptions to the rule
While most people can trust their “thirst mechanism”, there are some groups who should be more conscious of how much fluid they drink:
- Certain medications (e.g. for heart disease, ulcers or depression) can alter the thirst mechanism
- Certain chronic diseases, such as diabetes, can alter the thirst mechanism
- When you’re sick with a fever or experience diarrhoea and vomiting
- Women who are pregnant and breastfeeding
- Being in very hot, humid weather
 References:
- https://www.webmd.com/women/news/20120120/even-mild-dehydration-may-cause-emotional-physical-problems
- https://www.aifc.com.au/how-important-is-water-hydration-to-mental-health/
- https://idontmind.com/journal/youre-probably-dehydrated-and-it-can-affect-your-mental-health
- https://www.everydayhealth.com/healthy-living/8-best-times-drink-water/