Drink plenty of water throughout the day to avoid dehydration
How much water should you drink a day? You probably know that it's important to drink plenty of fluids when the temperatures soar outside. But staying hydrated is a daily necessity, no matter what the thermometer says. Unfortunately, many of us aren't getting enough to drink, especially older adults. Older people don't sense thirst as much as they did when they were younger. And that could be a problem if they're on a medication that may cause fluid loss, such as a diuretic.
Benefits of drinking water
Water keeps every system in the body functioning properly. The Harvard Medical School Special Health Report 6-Week Plan for Health Eating notes that water has many important jobs, such as:
- carrying nutrients and oxygen to your cells
- flushing bacteria from your bladder
- aiding digestion
- preventing constipation
- normalizing blood pressure
- cushioning joints
- protecting organs and tissues
- regulating body temperature
- maintaining electrolyte (sodium) balance.
Giving your body enough fluids to carry out those tasks means that you're staying hydrated.
If you don't drink enough water each day, you risk becoming dehydrated. Warning signs of dehydration include weakness, low blood pressure, dizziness, confusion, or urine that's dark in color.
So how much water should you drink? Most people need about four to six cups of water each day.
How much water should you drink a day?
The daily four-to-six cup rule is for generally healthy people. It's possible to take in too much water if you have certain health conditions, such as thyroid disease or kidney, liver, or heart problems; or if you're taking medications that make you retain water, such as non-steroidal anti-inflammatory drugs (NSAIDs), opiate pain medications, and some antidepressants.
How much water a day should you drink if you fit into that category? There's no one-size-fits-all answer. Water intake must be individualized, and you should check with your doctor if you are not sure about the right amount for you.
But even a healthy person's water needs will vary, especially if you're losing water through sweat because you're exercising, or because you're outside on a hot day. If you're wondering how much water you should drink on those occasions, speak with your doctor, but a general rule of thumb for healthy people is to drink two to three cups of water per hour, or more if you're sweating heavily.
Tips for avoiding dehydration
It's not just water that keeps you hydrated. All beverages containing water contribute toward your daily needs. And it's a myth that caffeinated beverages or those containing alcohol are dehydrating because they make you urinate. They do, but over the course of the day, the water from these beverages still leads to a net positive contribution to total fluid consumption.
Of course, there are many reasons why water is still the better choice. Remember, sugary drinks can lead to weight gain and inflammation, which can increase your risk for developing diseases such as diabetes. Too much caffeine can give you the jitters or keep you from sleeping. And, alcohol intake should be limited to one drink per day for women, and 1-2 drinks per day for men.
To ward off dehydration, drink fluids gradually, throughout the day. An easy way to do this is to have a drink at each meal, as well as socially, or with medicine.
And know that you also get fluids from water-rich foods, such as salads, fruit, and applesauce.
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Water: How much should you drink every day?
Water is essential to good health. Are you getting enough? These guidelines can help you find out.
By Mayo Clinic StaffHow much water should you drink each day? It's a simple question with no easy answer.
Studies have produced varying recommendations over the years. But your individual water needs depend on many factors, including your health, how active you are and where you live.
No single formula fits everyone. But knowing more about your body's need for fluids will help you estimate how much water to drink each day.
What are the health benefits of water?
Water is your body's principal chemical component and makes up about 50% to 70% of your body weight. Your body depends on water to survive.
Every cell, tissue and organ in your body needs water to work properly. For example, water:
- Gets rid of wastes through urination, perspiration and bowel movements
- Keeps your temperature normal
- Lubricates and cushions joints
- Protects sensitive tissues
Lack of water can lead to dehydration — a condition that occurs when you don't have enough water in your body to carry out normal functions. Even mild dehydration can drain your energy and make you tired.
How much water do you need?
Every day you lose water through your breath, perspiration, urine and bowel movements. For your body to function properly, you must replenish its water supply by consuming beverages and foods that contain water.
So how much fluid does the average, healthy adult living in a temperate climate need? The U.S. National Academies of Sciences, Engineering, and Medicine determined that an adequate daily fluid intake is:
- About 15.5 cups (3.7 liters) of fluids a day for men
- About 11.5 cups (2.7 liters) of fluids a day for women
These recommendations cover fluids from water, other beverages and food. About 20% of daily fluid intake usually comes from food and the rest from drinks.
What about the advice to drink 8 glasses a day?
You've probably heard the advice to drink eight glasses of water a day. That's easy to remember, and it's a reasonable goal.
Most healthy people can stay hydrated by drinking water and other fluids whenever they feel thirsty. For some people, fewer than eight glasses a day might be enough. But other people might need more.
You might need to modify your total fluid intake based on several factors:
- Exercise. If you do any activity that makes you sweat, you need to drink extra water to cover the fluid loss. It's important to drink water before, during and after a workout.
- Environment. Hot or humid weather can make you sweat and requires additional fluid. Dehydration also can occur at high altitudes.
- Overall health. Your body loses fluids when you have a fever, vomiting or diarrhea. Drink more water or follow a doctor's recommendation to drink oral rehydration solutions. Other conditions that might require increased fluid intake include bladder infections and urinary tract stones.
- Pregnancy and breast-feeding. If you are pregnant or breast-feeding, you may need additional fluids to stay hydrated.
Is water the only option for staying hydrated?
No. You don't need to rely only on water to meet your fluid needs. What you eat also provides a significant portion. For example, many fruits and vegetables, such as watermelon and spinach, are almost 100% water by weight.
In addition, beverages such as milk, juice and herbal teas are composed mostly of water. Even caffeinated drinks — such as coffee and soda — can contribute to your daily water intake. But go easy on sugar-sweetened drinks. Regular soda, energy or sports drinks, and other sweet drinks usually contain a lot of added sugar, which may provide more calories than needed.
How do I know if I'm drinking enough?
Your fluid intake is probably adequate if:
- You rarely feel thirsty
- Your urine is colorless or light yellow
Your doctor or dietitian can help you determine the amount of water that's right for you every day.
To prevent dehydration and make sure your body has the fluids it needs, make water your beverage of choice. It's a good idea to drink a glass of water:
- With each meal and between meals
- Before, during and after exercise
- If you feel thirsty
Should I worry about drinking too much water
Drinking too much water is rarely a problem for healthy, well-nourished adults. Athletes occasionally may drink too much water in an attempt to prevent dehydration during long or intense exercise. When you drink too much water, your kidneys can't get rid of the excess water. The sodium content of your blood becomes diluted. This is called hyponatremia and it can be life-threatening.
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Oct. 12, 2022
- Office of Patient Education. The heat is on! Precautions for people with diabetes during the summer months. Mayo Clinic, 2018.
- Auerbach PS, et al., eds. Dehydration and rehydration. In: Auerbach's Wilderness Medicine. 7th ed. Elsevier; 2017. //www.clinicalkey.com. Accessed Oct. 9, 2020.
- Water & nutrition. U.S. Centers for Disease Control and Prevention. //www.cdc.gov/healthywater/drinking/nutrition/index.html. Accessed Oct. 2, 2020.
- Dietary reference intakes for electrolytes and water. U.S. National Academies of Science, Engineering, and Medicine. //www.nationalacademies.org/our-work/dietary-reference-intakes-for-electrolytes-and-water. Accessed Oct. 2, 2020.
- Franklin BA. Exercise prescription and guidance for adults. //www.uptodate.com/contents/search. Accessed Oct. 2, 2020.
- High-altitude travel & altitude illness. U.S. Centers for Disease Control and Prevention. //wwwnc.cdc.gov/travel/yellowbook/2020/noninfectious-health-risks/high-altitude-travel-and-altitude-illness. Accessed Oct. 2, 2020.
- Bardosono S, et al. Pregnant and breastfeeding women: Drinking for two. Annals of Nutrition & Metabolism. 2017; doi:10.1159/000462998.
- Sterns RH. Maintenance and replacement fluid therapy in adults. //www.uptodate.com/contents/search. Accessed Oct. 2, 2020.
- Gordon B. How much water do you need. Academy of Nutrition and Dietetics. //www.eatright.org/food/nutrition/healthy-eating/how-much-water-do-you-need. Accessed Oct. 2, 2020.
- 10 tips: Make better beverage choices. U.S. Department of Agriculture. //www.choosemyplate.gov/ten-tips-make-better-beverage-choices. Accessed Oct. 2, 2020.
- Thomas DT, et al. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and American College of Sports Medicine: Nutrition and athletic performance. Medicine & Science in Sports & Exercise. 2016; doi:10.1016/j.jand.2015.12.006.
- Armstrong LE, et al. Water intake, water balance, and the elusive daily water requirement. Nutrients. 2018; doi:10.3390/nu10121928.
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