Running Gels: Hydration, Performance, and Proper Usage for Athletes

Do running gels dehydrate you?

Running gels, when consumed correctly alongside adequate water, do not dehydrate you. However, consuming them without sufficient fluid can transiently draw water into the digestive tract, potentially leading to gastrointestinal distress and contributing to an overall fluid imbalance.

Understanding Running Gels

Running gels are highly concentrated carbohydrate formulations designed to provide a quick and easily digestible source of energy for endurance athletes. Their primary purpose is to replenish glycogen stores and maintain blood glucose levels during prolonged physical activity, thereby delaying fatigue and enhancing performance. While their exact composition varies by brand, they typically contain simple and complex carbohydrates (e.g., maltodextrin, fructose, glucose), often supplemented with electrolytes (sodium, potassium) and sometimes caffeine.

The Dehydration Myth vs. Reality

The concern that running gels might dehydrate you stems from their high concentration of carbohydrates and other solutes. When ingested, these concentrated substances need water to be properly digested, absorbed, and transported throughout the body. The "myth" part arises when individuals consume gels without simultaneously taking in enough fluid.

The Reality: Gels themselves do not directly remove water from your body in a way that causes systemic dehydration. Instead, the potential issue lies in the osmotic effect within your digestive tract.

Osmolality and Fluid Balance: The Scientific Explanation

To understand the interaction between gels and hydration, we must consider osmolality. Osmolality refers to the concentration of solutes (like carbohydrates and electrolytes) in a solution.

• Hypertonic Nature of Gels: Running gels are typically hypertonic, meaning they have a higher osmolality (more concentrated solutes) than your blood plasma.
• Osmosis in the Gut: When you consume a hypertonic gel, your body's natural response is to try and balance the solute concentration. Water from your bloodstream and surrounding tissues is drawn into your gastrointestinal tract to dilute the concentrated gel. This process, known as osmosis, facilitates the absorption of the carbohydrates.
• Potential for Transient Issues: If you consume a gel without accompanying water, this inward movement of fluid into the gut can temporarily reduce the circulating blood volume. While this doesn't equate to clinical dehydration, it can contribute to a feeling of thirst, slow down gastric emptying, and potentially lead to gastrointestinal distress such as bloating, cramping, or diarrhea, especially during intense exercise when blood flow to the gut is already compromised.

Key Ingredients and Their Impact

The ingredients in running gels play a crucial role in their impact on fluid balance:

• Carbohydrates: The primary energy source. Glucose, fructose, and maltodextrin are common. While essential for fuel, their high concentration is what makes gels hypertonic. Adequate water is needed to process these effectively.
• Electrolytes (Sodium, Potassium): Many gels include electrolytes, particularly sodium. Sodium is vital for maintaining fluid balance, nerve function, and muscle contraction. Its presence in gels can actually aid in water absorption in the small intestine and help replace losses from sweat, thereby mitigating the risk of dehydration.
• Caffeine (Optional): Some gels contain caffeine. While caffeine has a mild diuretic effect, the amount typically found in a single gel is generally too small to cause significant dehydration in trained athletes during exercise. The benefits for performance enhancement usually outweigh this minor diuretic effect.

Proper Usage: Preventing Issues

The key to preventing any potential negative impact of running gels on hydration is proper usage:

• Always Consume with Water: This is the most critical rule. Aim to consume 150-250 ml (5-8 fl oz) of water immediately after or concurrently with each gel. This dilutes the gel, bringing its osmolality closer to that of blood plasma, which facilitates faster gastric emptying and absorption, and minimizes the osmotic pull of water into the gut.
• Train Your Gut: Practice your fueling strategy during training, not just on race day. This allows your digestive system to adapt to the gels and the accompanying fluid intake.
• Listen to Your Body: Pay attention to thirst cues. Thirst is your body's primary signal for needing fluid.
• Individual Needs: Sweat rates and electrolyte losses vary significantly among individuals. Tailor your hydration and fueling strategy to your personal needs and environmental conditions.

Signs of Dehydration and Over-hydration (Hyponatremia)

While the focus is on dehydration, it's also important to be aware of the opposite extreme:

• Signs of Dehydration:
  • Increased thirst
  • Dry mouth
  • Fatigue and lethargy
  • Dark urine or infrequent urination
  • Dizziness or lightheadedness
  • Decreased performance
• Signs of Over-hydration (Hyponatremia): This condition, characterized by dangerously low blood sodium levels, is typically caused by consuming excessive amounts of plain water without adequate electrolyte replacement, rather than by gels themselves. However, an overall poor hydration strategy can contribute.
  • Nausea and vomiting
  • Headache
  • Confusion
  • Swelling in hands, feet, or face
  • In severe cases, seizures or coma

Best Practices for Fueling and Hydration

To optimize your performance and health during endurance activities:

• Start Hydrated: Begin your run or event well-hydrated.
• Hydrate Regularly: Sip fluids consistently throughout your activity, rather than chugging large amounts at once.
• Combine Water and Electrolyte Drinks: For longer efforts, alternate between plain water and an electrolyte-rich sports drink. This helps maintain both fluid and electrolyte balance.
• Personalized Fueling Plan: Develop a personalized plan that accounts for the duration and intensity of your exercise, environmental conditions, and your individual sweat rate. Consider working with a sports dietitian or coach.

Conclusion: The Bottom Line

Running gels are a valuable and effective tool for endurance athletes, providing readily available energy to sustain performance. When used correctly – always consumed with an adequate amount of water – they do not cause dehydration. The perceived dehydrating effect is a misunderstanding of the osmotic process. By understanding how gels work and implementing a smart, integrated hydration and fueling strategy, athletes can harness their benefits without compromising fluid balance.