Staying properly hydrated is always the healthy choice, but it’s especially important to pay attention to your fluid intake during the hot days of summer. Many factors determine how much hydration is enough – or too much – but the basic guidelines below can help.
What is Proper Hydration?
Hydration can affect our heart rate, blood pressure, body temperature, waste removal, muscle and tissue health, and brain function. However, the amount of water an individual needs isn’t always easy to measure, and fluid requirements vary from person to person depending on their sex, age, diet, activity level, and environment. Conditions such as kidney disease and pregnancy can affect your recommended fluid intake, and some medications can change your body’s fluid needs.
Some experts recommend drinking 6-8 glasses of water per day, but that can vary depending on the size of the glass, your overall health, and your activity level at any given time. Another way to estimate proper fluid intake is to match the number of ounces you drink per day with half the number of pounds you weigh. For example, a person who weighs 150 pounds should drink 75 ounces (2.2 liters) of water per day under normal circumstances.
You can keep tabs on your hydration level by watching for these positive signs:
- Ability to sweat
- Frequent urination (4-8 times per day)
- Pale or almost clear urine
- Normal skin elasticity
- Not feeling thirsty
If you have kidney disease or a condition that affects your ability to urinate or sweat, then you should follow your doctor’s fluid intake guidelines carefully. You may need to limit your water intake to prevent an imbalance of certain electrolytes (minerals with an electrical charge) in your body.
When More Hydration is Needed
In most cases, staying hydrated isn’t something that most people have to worry about. But certain situations call for paying closer attention to your fluid intake to help prevent dehydration. These situations include:
- Extremely hot weather
- Extreme exertion due to work, exercise, sports, outdoor activity, etc.
- Illnesses that cause fever, diarrhea, and/or vomiting
- Alcohol consumption (drinking alcohol within 24 hours of exercising or playing in the heat can increase your risk of dehydration).
In these cases, you may get dehydrated if you drink less than your normal fluid intake. Being thirsty is not a sign that you are getting dehydrated, and not feeling thirsty does not mean your body has enough fluids. However, in any situation that creates a greater demand for fluids, you should drink before you begin feeling thirsty. By the time you feel thirsty, you may already be behind in fluid replacement. Being hydrated when you begin work or exercise makes it easier to stay hydrated throughout the day.
Too Much or Too Little?
If you lose more water than you take in, you can become dehydrated. Dehydration may cause muscle cramps, confusion, headaches, dizziness, or constipation. Mild dehydration may impact your mood and memory. These symptoms often go away once your body is rehydrated. You may need medical care if you suffer severe dehydration, since it can lead to more serious conditions.
In rare cases, it is possible to overhydrate. The body strives to continually maintain a balance of fluids and electrolytes in the bloodstream. Electrolytes such as sodium, potassium, chloride, and magnesium help manage muscle contraction, nervous system function, and the body’s acid/base balance. If you drink too much water and dilute the sodium in the blood too much, it may cause a condition known as hyponatremia (low salt levels in the blood).
Some of the symptoms of hyponatremia are the same as dehydration: nausea, vomiting, headaches, convulsions, and brain swelling. It can even cause death. Athletes running marathons or who perform in extremely hot weather are at higher risk of hyponatremia. This happens when they drink a large quantity of water, which stays in their bodies, while they lose a large amount of sodium by sweating.
Tips for Safer Hydration
- When working or playing in the heat, drink about 6 ounces of water every 15–20 minutes, or 24–32 ounces per hour.
- Drinking several times within a given period of time is more effective than drinking large amounts less often.
- Don’t overdo it. Drinking more than 48 ounces of fluids per hour may reduce salt levels in your blood.
- It may take several hours to drink enough fluids to replace what you lost through sweating. The sooner you get started, the less strain you place on your body from dehydration.
- Hydrating after work is even more important if you work in the heat on a regular basis.
- For prolonged sweating that lasts several hours, sports drinks with balanced electrolytes are another option to replace lost salt. However, keep in mind that some sports drinks have as much sugar as soft drinks and will add calories to your diet.
Water is almost always enough to maintain hydration during work in the heat, as long as you eat regular meals to replace the salt lost from sweating. In most cases, that lost salt can be replaced by eating normal meals and snacks throughout the day. The amount of caffeine in tea, coffee, and soft drinks usually does not affect overall hydration. In general, combining regular meals with adequate water intake is enough to maintain a healthy fluid and electrolyte balance in the body.
SOURCE: National Institutes for Health