Quick Answer
The recommended daily intake of water is around 2 litres for women and 2.5 litres for men. Drinking 1 litre or less may be insufficient for most people. However, water needs can vary greatly based on factors like age, activity levels, health conditions, and climate. It’s generally best to drink water when thirsty and with meals, while also monitoring urine color. Those with medical conditions or on restricted diets should consult a doctor.
How Much Water Does The Average Person Need?
The Institute of Medicine recommends that men consume around 3 litres (13 cups) of total beverages per day and women consume 2.2 litres (9 cups) per day. This includes water, other drinks, and moisture from foods.
About 20% of daily fluid intake usually comes from food and the remaining 80% should come from drinks. So based on these recommendations, men should get about 2.5 litres and women should get around 2 litres of water and other fluids per day.
However, water needs can vary substantially based on factors like age, body size, activity levels, sweat rates, pregnancy status, breastfeeding status, health conditions, medications, and climate.
Water Intake Recommendations By Age
| Age | Recommended Total Water Intake (From Food and Drink) |
|---|---|
| Infants 0-6 months | 0.7 litres per day |
| Infants 7-12 months | 0.8 litres per day |
| Children 1-3 years | 1.3 litres per day |
| Children 4-8 years | 1.7 litres per day |
| Boys 9-13 years | 2.4 litres per day |
| Girls 9-13 years | 2.1 litres per day |
| Boys 14-18 years | 3.3 litres per day |
| Girls 14-18 years | 2.3 litres per day |
| Adult men 19+ years | 3.7 litres per day |
| Adult women 19+ years | 2.7 litres per day |
As shown, water needs increase with age and are higher for males than females starting in adolescence. Older adults also tend to have decreased thirst sensation so they need to consciously drink more.
Factors That Increase Water Needs
Some situations and conditions increase water requirements including:
- High activity levels and exercise
- Hot weather or high altitude environments
- Fever, vomiting, or diarrhea
- Pregnancy and breastfeeding
- Large body size or high muscle mass
- High sodium, protein, caffeine, or alcohol intake
- Chronic kidney disease or diabetes
- Frequent air travel
People who sweat heavily with exercise may need 4 litres or more per day. Endurance athletes are commonly advised to try to replace each pound lost during activity with 16-24 oz of fluid.
Is 1 Litre Enough Water Per Day?
For most healthy adults living in temperate environments, 1 litre of water per day is likely not enough for optimal hydration and health. However, the adequacy can vary substantially based on the individual.
Some signs that 1 litre may be insufficient include:
- Consistently feeling thirsty
- Fatigue and headaches
- Dark yellow or amber colored urine
- Dry mouth
- Dizziness upon standing up
- Reduced urine output or constipation
However, there are some exceptions where 1 litre per day may be adequate:
- Smaller body sizes or lower activity levels
- Consumption of fluids from foods like fruits, vegetables, juices, milk, etc
- Cooler ambient temperatures
- Kidney conditions causing increased urine output
Some sources of moisture in foods include:
| Food | Water Content |
|---|---|
| Watermelon | 92% |
| Milk | 87-90% |
| Yogurt | 74-85% |
| Soups | 70-95% |
| Fruits | 70-95% |
| Vegetables | 75-95% |
| Bread | 35% |
So for some more sedentary people who consume a lot of foods with high moisture content, 1 litre from fluids alone may be sufficient. But for most active individuals, 1 litre is likely inadequate.
Health Risks of Drinking Too Little Water
Mild dehydration occurs when fluid losses exceed fluid intake by just 1-2% of body weight. Chronic mild dehydration can occur when people consistently drink too little throughout days or weeks.
Potential risks and effects of mild dehydration include:
- Digestive issues like constipation
- Kidney stones
- Bladder and urinary tract infections
- Increased risk of kidney disease
- Impaired physical and cognitive performance
- Daytime fatigue and headaches
- Reduced blood volume and flow
- Increased blood viscosity and risk of clots
- Reduced heart health
- Electrolyte imbalances
- Skin dryness and wrinkling
- Increased disease risk from concentrated urine
More severe dehydration, occurring with 5% or more fluid loss, can also cause confusion, weakness, delirium, organ damage, unconsciousness, and even death in extreme cases.
Some groups at higher risk of dehydration include athletes, people living in hot climates, older adults, young children, and people with certain conditions like diabetes or diarrhea. Being aware of risk factors and drinking sufficient water is key.
Tips for Consuming More Water
Here are some tips for increasing water intake if 1 litre per day seems insufficient:
- Drink a glass of water with each meal and snack
- Carry a water bottle throughout the day for frequent sipping
- Choose water over sugary drinks like soda, juice, and sports drinks
- Flavor water with fruits, herbs, or sparkling water for variety
- Set reminders to drink water throughout the day
- Consume water rich foods like fruits, vegetables, broth soups, yogurt, etc
- Monitor urine color and aim for pale lemonade color
- Be especially mindful of hydration before, during, and after physical activity
- Adjust water intake based on sweat losses and climate conditions
Remember that water needs can vary day to day and person to person based on many factors. Aim to drink to satisfy thirst and have pale clear urine while also considering activity levels, health conditions, medications, and environmental temperatures in determining optimal fluid intake.
Should You Force Yourself to Drink More?
While chronic mild dehydration can negatively impact health in many ways, there’s no need to force yourself to drink excessive amounts.
In healthy individuals, the body regulates hydration through thirst and balancing fluid intake and urine output. So relying on thirst as a cue to drink extra fluids when necessary is an adequate strategy for most. Exceptions include competitive athletes, older adults, and people with impaired thirst mechanisms.
Drinking far beyond thirst can put someone at risk of overhydration or hyponatremia. This occurs when excessive water intake dilutes the sodium content in blood to dangerously low levels.
Therefore, moderation is key. Drink enough to satisfy thirst, promote light clear urine, and account for extra losses from sweat, travel, illness, etc. But don’t force yourself to excessively consume more than this without medical reason.
Signs of Overhydration
- Headaches
- Nausea
- Vomiting
- Muscle cramps
- Fatigue
- Confusion
- Seizures
- Unconsciousness
These occur when sodium levels drop too low from over-consumption of plain water. So sports drinks with electrolytes may be a better choice than plain water during prolonged endurance exercise to maintain proper sodium balance.
General Tips for Adequate Hydration
Here are some general tips for maintaining proper hydration with water and other fluids:
- Drink when thirsty and with meals or snacks
- Choose water as the primary beverage
- Drink before, during and after exercise based on sweat losses
- Increase fluids in hot climates or at altitude
- Consume water-rich foods like fruits and veggies
- Limit diuretics like caffeine and alcohol
- Monitor urine color for pale lemonade appearance
- Account for increased needs during sickness, travel, or heavy sweating
- Carry a water bottle for frequent sipping
- Avoid forcing excess water beyond thirst if healthy
Sticking to these tips will help ensure your individual water needs are met based on your health, activities, and environment.
When to See a Doctor
Most healthy people can stay well hydrated by drinking to satisfy thirst. But consult a doctor if you experience signs of dehydration, have increased fluid needs due to an underlying condition, or need help determining optimal water intake.
See a doctor promptly for evaluation if you experience symptoms like:
- Fatigue, confusion, or disorientation
- Infrequent urination or very dark urine
- Extreme thirst even after drinking
- Fainting or dizziness upon standing
- Persistent nausea or vomiting
- Muscle cramps during exercise
These can indicate moderate to severe dehydration, especially when combined with inadequate fluid intake. Timely treatment is important to restore fluids and electrolytes.
People with medical conditions like diabetes, heart failure, kidney disease, bladder issues, or chronic diarrhea may also need guidance on optimal water intake. Your doctor can help determine the right amount for your individual health status and medication use.
Conclusion
For most healthy adults, 1 litre of water per day is likely not optimal for hydration. General recommendations suggest at least 2 litres for women and 2.5 litres for men daily from fluids and foods combined. However, water needs vary substantially by individual.
Relying on thirst, monitoring urine color, accounting for extra losses from sweat or illness, and drinking water with meals is the best way to meet your needs. Drink enough to avoid dehydration symptoms, but avoid forcing excess intake beyond thirst without medical reason. With the right strategies tailored to your unique situation, staying well hydrated with clean water can promote optimal health.
