Recent Blog Articles

How much water should you drink?

May 15, 2022

Drink plenty of water throughout the day to avoid dehydration

Water being poured into a tall glass.

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.

Image: taa22/Getty images

Disclaimer:

As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Free Healthbeat Signup

Get the latest in health news delivered to your inbox!

Harvard Health Publishing Logo

Thanks for visiting. Don't miss your FREE gift.

The Best Diets for Cognitive Fitness, is yours absolutely FREE when you sign up to receive Health Alerts from Harvard Medical School

Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.

Harvard Health Publishing Logo

Health Alerts from Harvard Medical School

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss...from exercises to build a stronger core to advice on treating cataracts. PLUS, the latest news on medical advances and breakthroughs from Harvard Medical School experts.

BONUS! Sign up now and
get a FREE copy of the
Best Diets for Cognitive Fitness

Harvard Health Publishing Logo

Stay on top of latest health news from Harvard Medical School.

Plus, get a FREE copy of the Best Diets for Cognitive Fitness.