If you find that you consistently fight against fatigue during the day, you may be low on an important energy source: Water. That’s because water is more than just a thirst-quencher – it’s a vital fuel for your body and your brain. Whether you're tackling a busy day at work or pushing through a weekend workout, drinking enough water can significantly impact your energy levels, concentration, and overall performance.

How Water Supports Energy and Focus

Your body is made up of 50-70% water, and sends signals, like thirst, with even the slightest drop of 1-2% in your water level. When you're well-hydrated, your brain cells receive the nutrients and oxygen they need to operate efficiently, helping you stay focused and clear-headed throughout the day.

Water also plays a crucial role in maintaining energy. Without adequate fluids, your heart works harder to pump blood, and your muscles can tire more quickly. This leads to sluggishness, fatigue, and less stamina for both mental and physical tasks. Insufficient water intake can also leave you feeling cranky and irritated.

How Much Water Do You Need?

The classic advice is to aim for 8 cups (64 ounces) of water per day. However, individual needs may vary. A more personalized daily baseline is:

• Men: ~3.7 liters (125 ounces)
• Women: ~2.7 liters (91 ounces)

When You May Need More Water

Most people benefit from increasing their water intake, especially under certain conditions. You may need extra fluids if you:

• Are physically active or exercising
• Spent time in hot or humid weather
• Have a fever or are experiencing vomiting or diarrhea
• Are pregnant or breastfeeding

In these situations, your body loses fluids more quickly and needs more to stay hydrated and function properly.

When You May Need Less Water

While rare, some individuals need to monitor and limit how much water they consume. This can include people with kidney disease, heart failure, or other conditions that affect fluid balance.

Too much fluid can overwhelm the body, especially when the kidneys aren’t working at full capacity.

It’s also possible to drink too much water in a short period of time, which can lead to hyponatremia—a condition where sodium levels in the blood become dangerously low. This most often affects endurance athletes during prolonged exercise.

If you’re unsure how much water is right for you, talk to your healthcare provider for personalized guidance based on your health and lifestyle.

Don't Forget the Water in Your Food

Those hydration totals include all fluids you consume—not just water from your bottle, but also from other beverages and food. In fact, about 20% of your daily water intake typically comes from food. For example:

• A cup of watermelon or strawberries is over 90% water
• Cucumbers, lettuce, and celery are also more than 90% water
• Soups, smoothies, and yogurt contribute, too

If your target is 91 ounces a day and you’re eating a diet rich in fruits and vegetables, you may only need to drink around 70–75 ounces of fluid from beverages.

That said, plain water remains the healthiest, most efficient way to hydrate—so make it your first choice whenever possible.

Understand the Signs of Dehydration

Dehydration happens when your body loses more fluids than it takes in, leaving it without enough water to carry out normal functions. Even mild dehydration can affect your mood, energy, and ability to concentrate—so it’s important to catch it early.

Here are some common signs to watch for:

• Feeling thirsty
• Headache, dizziness, or lightheadedness
• Dry mouth
• Fatigue or low energy
• Urinating less often or having dark-colored urine

In infants and children, dehydration can show up a little differently. Watch for:

• Infants: dry mouth, sunken soft spot, few or no tears when crying, or fewer wet diapers
• Older children: complaints of dry mouth, fatigue, or being less active than usual

If you’re concerned that a child is dehydrated, call your pediatrician for guidance

Hydration Tips

• Start your day with a glass of water.
• Carry a reusable water bottle to sip throughout the day.
• Flavor your water with lemon, cucumber, or mint, or drink unsweetened sparkling water, for variety.

It’s important to note that while sports drinks may be suitable during periods of intense physical activities, particularly for adults, water should be the beverage of choice for most people, particularly children and non-athletes. Many sports drinks contain sugar, minerals, and electrolytes that can cause issues in children, or if they are over-consumed.

Staying hydrated is a simple way to boost focus and energy to help you power through your activities at work, and at play. Don’t underestimate the power of water!