How to Stay Hydrated: Evidence-Based Patient Guidance
You do not need to drink plain water to stay hydrated—any beverage you enjoy, including coffee, tea, milk, juice, soup, and even moderate amounts of beer or lager, will keep you properly hydrated. 1
What Counts as Hydrating Fluids
The myth that only plain water hydrates you needs to be dispelled. All of the following beverages effectively hydrate your body: 1
- Water (plain, sparkling, or flavored)
- Hot or cold tea and coffee (including caffeinated versions)
- Milk and milky drinks
- Fruit juices and smoothies
- Soups
- Sports drinks and soft drinks
- Beer and lager (if you don't have medical reasons to avoid alcohol)
Important Evidence About Coffee and Alcohol
Despite common concerns, coffee does not cause dehydration, even when caffeinated. 1 Research demonstrates that caffeinated beverages hydrate just as effectively as water. 1
Alcoholic drinks up to 4% alcohol content (like most beers and lagers) are hydrating. 1 The hydration effect of drinks with higher alcohol content remains unclear and requires more research. 1
How Much Should You Drink
Aim for approximately 1.5 liters (about 6 cups) of fluid daily as a baseline. 1, 2 This amount applies to healthy adults in temperate climates with sedentary lifestyles. 2
When You Need More Fluids
Increase your fluid intake during: 1
- Hot weather or extreme temperatures
- Physical activity or exercise
- Fever, diarrhea, or vomiting
- Pregnancy
- Any period of fasting
The "8 glasses of water per day" rule lacks rigorous scientific evidence and is not necessary for most healthy adults. 3 Your body's thirst mechanism is highly precise and effective at maintaining proper hydration. 2
Practical Strategies to Stay Hydrated
Choose Beverages You Actually Enjoy
Drink what you prefer—variety and enjoyment promote better fluid intake. 1 Select beverages based on both your taste preferences and their nutritional content. 1 Milky drinks, fruit juices, and smoothies provide additional nutritional benefits in certain situations. 1
Make Fluids Easily Accessible
Keep drinks readily available throughout your day. 1 Physical access to beverages is a common barrier to adequate hydration, particularly for older adults. 1
Drink Regularly, Not Just When Thirsty
While thirst is an effective signal, establish regular drinking patterns throughout the day. 1 Social drinking occasions and routine mealtimes serve as important triggers for fluid intake. 1
During Exercise
For physical activity lasting less than 1 hour, plain water or any preferred beverage is adequate. 4 For exercise exceeding 1 hour, consume 600-1200 mL per hour of fluids containing 4-8% carbohydrates. 4 Drink fluids cooled to 15-22°C (59-72°F) to enhance palatability. 4
Special Considerations and Cautions
When to Restrict Fluids
Heart failure and kidney failure may require fluid restriction—follow your physician's specific recommendations. 1 These conditions represent important exceptions to general hydration advice.
Continence Concerns
If urinary frequency is problematic, you may try decaffeinated beverages, though they are not necessary unless you find them helpful. 1 Do not restrict your overall fluid intake due to continence concerns, as this increases dehydration risk. 1
Signs You May Need More Fluids
Monitor for dehydration symptoms including: 2
- Decreased consciousness or confusion
- Weakness
- Low blood pressure when standing
- Rapid heart rate
Common Pitfalls to Avoid
Do not assume you must drink plain water to be healthy. 1 This misconception leads many people to drink less than they need because they dislike plain water. 1
Do not wait until you feel extremely thirsty, especially if you are older, as the thirst response diminishes with age. 1 Establish regular drinking habits instead. 1
Do not avoid all caffeinated or alcoholic beverages thinking they dehydrate you—moderate amounts contribute positively to your daily fluid intake. 1