Should You Drink Water a Lot During a Workout or Take Small Sips?

Water is essential for life, and its importance becomes even more pronounced during physical activity. When you work out, your body sweats to regulate temperature, losing water and electrolytes in the process. But how much water should you drink during exercise, and what’s the best way to hydrate—gulping down large amounts or sipping gradually? Let’s explore the science and practical considerations to find the optimal approach.

The Science of Hydration During Exercise

Exercise increases your body’s demand for water. According to a 2016 study published in the Journal of Sports Sciences, dehydration as little as 2% of body weight can impair physical performance, reduce endurance, and increase perceived effort (Sawka et al., 2015). This happens because water plays a critical role in delivering oxygen to muscles, regulating body temperature, and maintaining blood volume.

The American College of Sports Medicine (ACSM) recommends that individuals aim to prevent excessive dehydration during exercise by drinking fluids based on their sweat rate and the duration and intensity of the workout. Sweat rates vary widely—anywhere from 0.3 to 2.4 liters per hour—depending on factors like body size, fitness level, climate, and exercise intensity (ACSM Position Stand, 2007).

Drinking a Lot vs. Small Sips: What Does the Research Say?

1. Large Gulps of Water
   Drinking a lot of water at once might seem like a good way to stay ahead of dehydration, especially during intense or prolonged workouts. However, research suggests that overloading your stomach with fluid can lead to discomfort. A 2014 study in Medicine & Science in Sports & Exercise found that consuming large volumes of water (e.g., 500 mL or more) in a single go during exercise can cause gastric distress, bloating, or a sloshing sensation, particularly during high-impact activities like running (Gisolfi & Summers, 1994). Your stomach can only empty fluid at a rate of about 600-1200 mL per hour, depending on individual factors and the presence of carbohydrates or electrolytes in the drink.
2. Small Sips
   Taking small, frequent sips—typically 150-250 mL every 15-20 minutes—is widely recommended by sports scientists. This approach aligns with the body’s ability to absorb water efficiently without overwhelming the stomach. A 2019 review in Sports Medicineconcluded that sipping water regularly during exercise helps maintain hydration status without causing gastrointestinal issues, making it ideal for most people (Burke & Hawley, 2019). It also allows for a steady supply of fluid to replace what’s lost through sweat.

How Much Water Do You Actually Need?

The “right” amount of water depends on your workout and your body. The ACSM suggests drinking 5-10 mL of water per kilogram of body weight (about 2.3-4.5 mL per pound) in the 2-4 hours before exercise to start hydrated. During exercise, aim to replace fluid losses by drinking 400-800 mL per hour, adjusted for your sweat rate and conditions. For example:

• A 150-pound (68 kg) person might need 150-300 mL every 15-20 minutes during moderate exercise in a temperate climate.
• In hot, humid conditions or during intense sessions, this could increase.

Overhydration, though rare, is a risk. Drinking too much water without replacing electrolytes can lead to hyponatremia, a dangerous condition where sodium levels in the blood drop too low. A 2005 study in the New England Journal of Medicine highlighted cases of hyponatremia in marathon runners who consumed excessive water without balancing electrolytes (Almond et al., 2005).

Practical Tips: Sips or Gulps?

• Short Workouts (Under 60 Minutes): For moderate exercise lasting less than an hour, small sips of water (150-250 mL every 15 minutes) are usually sufficient, especially if you’re hydrated beforehand. Gulping large amounts is unnecessary and may feel uncomfortable.
• Long or Intense Workouts (Over 60 Minutes):For endurance activities or high-intensity sessions, sipping water regularly—potentially with added electrolytes (e.g., from a sports drink)—is ideal. Larger gulps might be tempting during breaks, but keep them moderate (300-400 mL) to avoid stomach upset.
• Listen to Your Body: Thirst is a reliable indicator for most people. If you feel parched, sip water rather than chugging to catch up.

The Verdict

Scientific evidence leans toward small, frequent sips as the best hydration strategy during a workout. This method supports steady fluid replacement, minimizes discomfort, and aligns with how your body processes water. Drinking a lot at once can work in specific scenarios—like a quick rehydration break during a long event—but it’s not ideal for most exercisers.

To optimize your hydration, start your workout well-hydrated, sip 150-250 mL every 15-20 minutes during exercise, and adjust based on your sweat rate and conditions. For workouts exceeding an hour or in extreme heat, consider electrolyte-enhanced drinks. Staying hydrated doesn’t mean drowning your system—it’s about balance.

By Vitalina Andrushchenko, Staff Writer