What Should Be Avoided to Prevent Dehydration During Exercise?

January 8, 2026 •

4 min read

According to the American Council on Exercise, a fluid loss equal to just two percent of body mass can cause a detectable decrease in athletic performance. Avoiding certain drinks and habits is crucial for anyone engaging in physical activity, from a casual jog to an intense workout. Understanding these pitfalls is the first step toward maintaining optimal hydration and safeguarding your health during exercise.

Quick Summary

This article details the key items, drinks, and habits to avoid when exercising to prevent dehydration. It covers the pitfalls of relying on thirst, consuming high-sugar or caffeinated beverages, and ignoring environmental factors.

Key Points

Avoid Excessive Caffeine: Limit highly caffeinated drinks, which act as diuretics and increase fluid loss during exercise.
Skip High-Sugar Beverages: Stay away from sodas and sugary juices, as their high carbohydrate content can delay rehydration and cause stomach upset.
Do Not Rely Solely on Thirst: Thirst is a late signal of dehydration; develop a proactive hydration plan, especially for intense or prolonged workouts.
Abstain from Alcohol: Avoid alcohol before and after exercise, as it is a potent diuretic that impairs hydration and recovery.
Be Mindful of Environmental Conditions: Avoid exercising during peak heat and humidity, or move your workout indoors, to minimize excessive fluid loss.
Don't Overlook Electrolytes: For longer or more intense sessions, avoid relying on plain water alone, as it fails to replace essential lost electrolytes.

Common Mistakes to Avoid for Optimal Hydration

Proper hydration is a cornerstone of effective and safe exercise, yet many people unwittingly sabotage their efforts by making preventable mistakes. Knowing what to avoid is as important as knowing what to do. From a lack of pre-workout planning to poor beverage choices, these common errors can quickly lead to fluid deficits that negatively impact your performance and well-being.

Ignoring Thirst Cues or Misunderstanding Their Timing

One of the most widespread misconceptions is that you only need to drink when you feel thirsty. In reality, thirst is often a lagging indicator, a signal that your body is already in a state of mild dehydration. For most people engaging in low-to-moderate intensity exercise, drinking to thirst is generally sufficient. However, for longer, more intense, or hotter workouts, relying on thirst alone can lead to a significant fluid deficit. Developing a proactive hydration plan is especially important for serious athletes and those in hot or humid conditions. This involves consuming fluids at regular intervals rather than waiting for your body's alarm system to activate.

Relying on High-Sugar Drinks for Hydration

While sports drinks have their place for high-intensity, prolonged exercise (over 60 minutes), many everyday options are counterproductive for hydration.

Soda and Fruit Juice: These beverages are loaded with simple sugars. Drinks with a high carbohydrate concentration (more than 8%) can delay gastric emptying, meaning fluids take longer to be absorbed by the body. This can cause stomach discomfort and slow down the rehydration process, which is the exact opposite of what you need during or after a workout.
Energy Drinks: Beyond the high sugar content, many energy drinks contain excessive amounts of caffeine. The combination of high sugar and caffeine can be significantly dehydrating, especially during intense exercise.

Consuming Excessive Caffeine and Alcohol

Caffeine and alcohol are both diuretics, meaning they cause your body to increase urine production and lose more fluid. While the diuretic effect of moderate caffeine is often offset by the fluid in the beverage itself, excessive intake, particularly before or during a workout, can contribute to fluid loss. Alcohol is a more potent diuretic and should be avoided entirely before, during, and immediately after exercise to prevent dehydration and aid proper recovery.

Working Out at the Wrong Time or in the Wrong Conditions

Exercising in peak heat and humidity significantly increases your sweat rate and, therefore, your risk of dehydration and heat-related illnesses. Your body’s ability to cool itself is compromised when humidity is high because sweat doesn't evaporate as effectively. To mitigate this risk, scheduling vigorous outdoor exercise during cooler parts of the day (early morning or evening) is essential. For extreme conditions, moving your workout indoors to a climate-controlled environment is the safest option.

Comparison of Hydrating vs. Dehydrating Beverages


Beverage Type	Hydration Effect	Best for During Exercise	Why It Works/Doesn't Work
Water	Highly Hydrating	Yes (Most workouts <60 min)	The body's primary hydration source, absorbed quickly and efficiently.
Electrolyte Drinks	Highly Hydrating	Yes (Endurance/High-Intensity)	Contains sodium and carbs to replace what's lost in sweat, aiding faster absorption.
Sodas/High-Sugar Juice	Dehydrating (Ineffective)	No	High sugar content slows gastric emptying, delaying hydration and causing GI distress.
Coffee/High-Caffeine Drinks	Potentially Dehydrating	No (High Intake)	Caffeine is a diuretic, increasing fluid loss, especially when consumed in excess.
Alcohol	Highly Dehydrating	Absolutely Not	Potent diuretic effect causes rapid fluid loss and impairs athletic performance and recovery.
Low-Sugar Coconut Water	Hydrating	Potentially (Moderate Exercise)	Contains natural electrolytes like potassium, but lower sodium than sports drinks.

Establishing a Better Hydration Strategy

To move beyond these avoided practices, focus on a proactive and mindful hydration strategy. Here's a quick guide to developing one:

Pre-Exercise Hydration: Begin your workout well-hydrated. The American Council on Exercise recommends drinking 17-20 ounces of water 2-3 hours before exercise and another 8 ounces 20-30 minutes before or during your warm-up.
During-Exercise Hydration: For most people, water is sufficient for workouts under 60 minutes. For longer, high-intensity sessions, particularly in heat, a carbohydrate-electrolyte sports drink can be beneficial. Aim for 7-10 ounces every 10-20 minutes.
Post-Exercise Rehydration: Post-workout, it's crucial to replace fluids lost. A simple method is to weigh yourself before and after exercise; for every pound lost, aim to drink 16-24 ounces of fluid. Combining fluid intake with electrolyte-rich foods and balanced macronutrients aids faster recovery.
Listen to Your Body: Pay attention to early signs of dehydration beyond just thirst, such as fatigue, muscle cramps, dizziness, or darker urine. Monitoring urine color is an easy, low-tech way to gauge your hydration status; it should be a pale yellow, like lemonade.

Conclusion: Strategic Hydration for Performance and Safety

To prevent dehydration during exercise, a strategic approach is necessary, focusing on avoiding common pitfalls while proactively managing fluid intake. Steer clear of high-sugar and highly caffeinated beverages, and abstain from alcohol, especially around workout times. Listen to your body and recognize that thirst is a sign that you are already mildly dehydrated. Instead of falling for common myths, create a mindful hydration schedule tailored to your activity level, intensity, and environmental conditions. By avoiding these dehydrating practices and adopting a smarter, proactive hydration strategy, you can protect your performance, enhance your recovery, and safeguard your overall health while staying active.

For more detailed sports nutrition guidelines, consult the National Institutes of Health (NIH) or a certified sports dietitian.

Frequently Asked Questions

You should avoid high-sugar drinks like soda and fruit juice, as their high carbohydrate content can slow down the body's absorption of fluids. Excessively caffeinated beverages and alcohol should also be avoided due to their diuretic effects.

No, it is not ideal to rely solely on thirst, especially during intense or prolonged exercise. Thirst is a signal that your body is already starting to experience dehydration. For better performance and safety, develop a proactive hydration schedule.

Yes, caffeine acts as a mild diuretic, increasing urine production. While moderate consumption is generally okay for habitual drinkers, excessive intake, especially when exercising, can increase fluid loss and should be avoided.

High-sugar energy drinks can delay the rehydration process by slowing gastric emptying, which can cause stomach distress and reduce fluid absorption. They also often contain high levels of caffeine, which further contributes to fluid loss.

Signs of dehydration include increased thirst, dark yellow urine, fatigue, dizziness, and muscle cramps. Monitoring your urine color is a good, simple indicator; it should be a pale yellow color, like lemonade.

For most workouts under 60 minutes, water is sufficient. For high-intensity or endurance exercise lasting over an hour, a sports drink containing carbohydrates and electrolytes may be beneficial to replace lost salts and fuel.

High heat and humidity increase your sweat rate. In humid conditions, sweat doesn't evaporate as efficiently, which impairs your body's ability to cool itself and increases your risk of fluid loss.