Drinking enough water every day is important for overall health. The recommended number of glasses per day can vary based on factors like age, gender, activity levels, health conditions, and climate. As a general guideline, health experts often recommend drinking 6-8 glasses of water per day or about 1.5-2 liters. However, some people may need more or less than this depending on their individual needs.
Quick Answers
Here are some quick answers to common questions about daily water intake:
- The standard recommendation is 6-8 glasses of water per day or about 1.5-2 liters.
- Factors like age, gender, activity levels, health conditions, and climate impact needs.
- Increased physical activity and hotter climates cause the body to lose more water so intake should be increased.
- Thirst is not always a reliable indicator of hydration status so it’s important to drink water regularly throughout the day.
- Urine color, volume, and frequency are better indicators – light colored, abundant, frequent urination suggests adequate hydration.
- Water is best but other beverages like milk, juices, tea, and coffee also contribute to fluid intake.
- Fruits and vegetables with high water content also help meet fluid needs.
- Dehydration signs include thirst, fatigue, headache, dizziness, and dark yellow urine – these signal a need to drink more.
Why is Water Important?
Water makes up about 60% of the human adult body. It is essential for many vital bodily functions including:
- Regulating body temperature – Water helps the body sweat to cool down and maintain a consistent internal temperature.
- Lubricating joints – Water allows joints to move smoothly and reduces friction.
- Protecting organs and tissues – Water cushions organs and tissues.
- Removing waste – Water flushes waste and toxins from the body through urination, perspiration, and bowel movements.
- Aiding digestion – Water helps digest food and prevents constipation.
- Delivering nutrients – Water transports nutrients and oxygen to cells.
- Maintaining blood volume – Water composes a significant portion of blood and carries nutrients and oxygen.
Even mild dehydration of 1-2% loss of body weight can impair concentration, mood, digestion, circulation and other functions. Severe dehydration can be life threatening. Drinking enough water daily prevents dehydration and allows the body to perform essential biochemical reactions.
Factors that Determine Water Needs
While the standard baseline is 6-8 glasses per day, water needs can vary significantly based on the following factors:
Age
Infants and children have higher water needs relative to their size compared to adults because they are growing rapidly. Here are the recommended daily intakes by age:
- 0-6 months – 800-1,000 ml per day from breastmilk or formula
- 7-12 months – 900-1,200 ml per day from breastmilk, formula, foods and other drinks
- 1-3 years – 1,300 ml per day including water, milk and other beverages
- 4-8 years – 1,600 ml per day
Water needs decrease with age as growth and activity slow down. Recommendations for adults are:
- Men – 3.7 liters per day
- Women – 2.7 liters per day
However, elderly adults often have a reduced sense of thirst so they should remember to drink regularly even if not feeling thirsty.
Gender
Males generally need more water than females each day. This is because males typically have larger body sizes and more muscle mass than women. Muscles are about 75% water, so more muscles mean more fluid is needed. Males also perspire more than females.
Climate and Environment
Hot and humid climates cause the body to perspire more to achieve cooling. Greater water losses via perspiration must be replaced by higher water intake. Cold and dry air also increases respiratory water losses.
Environments with high altitudes result in faster breathing which causes greater insensible water losses via the lungs. Exposure to very hot or cold temperatures causes similar increases in respiratory water loss.
Physical Activity and Exercise
Vigorous exercise and physical labor cause significant sweating and water loss via perspiration. Losses of 0.5-2 liters per hour are common with sustained exercise. This needs to be replaced by drinking extra fluids before, during and after physical activity.
Health Conditions
Certain health conditions like diabetes insipidus, diabetes mellitus, hyperthyroidism, fever, vomiting or diarrhea can increase water needs and lead to excess water losses from the body that need to be replaced.
Kidney problems like kidney stones or chronic kidney disease can also increase daily fluid needs. Some medications like diuretics also result in increased urination and water loss.
Signs of Good Hydration
Signs that indicate you are drinking enough water include:
- Light yellow or nearly colorless urine – Dark urine means you need to drink more water.
- Infrequent urination – Needing to urinate about 4-7 times in 24 hours is ideal.
- Sufficient urine volume – Healthy urination produces about 100 ml or half a cup each time.
- Moist mucous membranes – For example, moist lips and mouth.
- Absence of thirst – Not feeling persistently thirsty throughout the day.
As long as you are urinating regularly, the color is light, and you are not feeling excessively thirsty, your water intake is likely adequate.
Signs of Dehydration
Symptoms that may indicate dehydration include:
- Thirst
- Dark yellow or amber colored urine
- Infrequent urination
- Small amounts of urine
- Dry mouth
- Fatigue
- Dizziness
- Headaches
- Muscle cramps
- Increased heart rate
- Confusion
If you are experiencing these symptoms, it is important to drink fluids immediately. Severe dehydration requires urgent medical treatment with IV fluids.
What Counts Towards Water Intake?
While water is the ideal source of hydration, other beverages also contribute to total fluid intake. Sources of water include:
- Plain water – From the tap, bottles, filters, etc. Most hydrating choice.
- Milk – Has high water content, provides hydration as well as protein, fat, and calcium.
- Fruit juice – Also provides hydration along with vitamins, minerals, and antioxidants.
- Vegetable juice – Provides hydration and nutrients without added sugars.
- Tea and coffee – Contribute to hydration, but caffeine has mild diuretic effect.
- Herbal tea – Hydrating and free of caffeine and calories.
- Sparkling water – Just as hydrating as regular water.
- Soup broths – Provide hydration as well as minerals from bones and vegetables.
- Fruits and vegetables – Their high water content contributes to fluid intake.
Sugary drinks like sodas and fruit juices high in added sugars are not ideal. Alcohol is also a diuretic so does not effectively hydrate.
Tips to Drink More Water
Here are some tips to help you drink enough fluids and stay hydrated every day:
- Carry a water bottle with you to sip from throughout the day.
- Set reminders to drink water at intervals, e.g. your phone alarm.
- Drink a glass of water first thing when you wake up and before each meal.
- Choose water or unsweetened beverages when eating out.
- Eat fruits and veggies high in water like cucumbers, berries, oranges, tomatoes.
- Add slices of lemon, lime, cucumber or watermelon to water for flavor.
- Try different temperatures – chilled water is refreshing while warm water aids digestion.
- Make a habit of refusing plastic water bottles – use your own reusable bottle instead.
How Much Water is Too Much?
Drinking too much water can result in a condition called water intoxication or hyponatremia. This happens when excessive water intake dilutes the sodium levels in blood, causing an electrolyte imbalance.
Healthy kidneys can typically excrete 0.8 to 1 liters of excess water per hour via the urine. So normal hydration within recommended guidelines is generally not a concern.
Those at greatest risk of hyponatremia include:
- Endurance athletes who drink very large amounts of fluids while exercising vigorously over prolonged periods.
- Participating in activities like marathons, triathlons, military training exercises.
- Using MDMA (ecstasy) which may increase thirst and fluid intake.
- Patients with underlying medical conditions like heart failure or kidney disease.
Symptoms of hyponatremia may include headache, nausea, vomiting, fatigue, disorientation, muscle weakness or spasms. It is a medical emergency requiring immediate treatment.
Prevent excessive water intake by not drinking over 1 liter per hour during intense physical activity. Eating salty foods helps replace sodium losses.
The Bottom Line
Here is a summary of key points on recommended water intake:
- The standard baseline is 6-8 glasses of water per day or 1.5-2 liters.
- Needs vary based on age, gender, activity level, climate, health conditions, etc.
- Higher water intake is needed with exercise, hot weather, high altitudes, and some health conditions.
- Water is best, but other fluids like milk and juice also contribute.
- Signs like urine color, thirst, and dizziness indicate if you are dehydrated.
- Drink when thirsty and spread water intake throughout the day.
- Excessive intake over 1 liter per hour can cause water toxicity so moderation is key.
Paying attention to your thirst cues, urine volume and color, and tuning in to your body’s signs of hydration are the best ways to determine your ideal water intake. Staying well hydrated provides enormous health benefits but too much can be problematic. Finding the right balance for your individual needs is key.
