Are You Hydrating For Best Performance?
Water is essential for an athlete’s performance, health, and longevity. Drinking too little water, or losing too much through sweat, can impair your ability to train effectively, think clearly, and recover fully.
But hydration isn’t only about replacing water. It’s about maintaining the body’s internal balance; the transport of nutrients, removal of waste, and regulation of temperature that allow the brain, muscles, and cardiovascular system to perform in sync.
Water is the body’s transport system: it delivers oxygen and glucose to working muscles, carries away metabolic waste like carbon dioxide and lactate, and cools the body through evaporation. When hydration falls short, these finely tuned systems begin to unravel.
Dehydration
The human body is roughly 60% water, and the brain about 70%. Research has shown that even a 2% loss in total body water can impair endurance, strength, and cognitive performance. Studies from the Journal of Applied Physiology and European Journal of Applied Physiology demonstrate that such mild dehydration increases perceived effort, slows reaction time, and reduces blood volume, forcing the heart to work harder to deliver oxygen.
Hydration needs vary among athletes depending on:
Baseline hydration before training or competition
Sweat rate, which differs by genetics, acclimatization, and conditioning
Body size, as larger athletes lose more fluid and electrolytes
Environmental conditions, with heat and humidity increasing sweat losses
Training intensity, since higher workloads accelerate fluid and sodium depletion
Endurance athletes, including standup paddlers, tend to sweat earlier and in larger volumes. Without conscious hydration, small imbalances can lead to rapid fatigue, poor focus, and slower recovery.
Hydration During Training or Competition
Sports nutrition research recommends a drink containing 4–8% carbohydrate solution during prolonged exercise. This concentration provides fuel for working muscles and enhances fluid absorption through sodium-glucose co-transport in the small intestine.
Fruit juices, on the other hand, often contain 9–12% carbohydrate, which can delay gastric emptying and cause gastrointestinal discomfort. Sports drinks, when properly formulated, provide the ideal blend of water, electrolytes (sodium, potassium, magnesium), and easily digestible carbohydrates to rehydrate efficiently.
If you have a sensitive stomach, experiment during training — not on race day — to identify brands and formulas that work best for you. Some athletes experience discomfort from fructose-heavy drinks or added caffeine, which can stimulate the gut or increase diuresis.
For SUP sessions lasting 30–60 minutes at low to moderate intensity, water alone is sufficient. For sessions beyond 60 minutes or in the heat, include a sports drink. Research suggests drinking 2–4 ounces (60–120 mL) every 15–20 minutes to maintain hydration. While that may seem minor, consistency matters — small, steady sips prevent both dehydration and gastric bloating.
During races, hydration packs or waist systems can make this process automatic, freeing you to focus on rhythm and performance.
Importantly, thirst is not a reliable signal during intense exercise, as the body’s thirst mechanism lags behind fluid loss and can be suppressed by high core temperature. Instead, pay attention to cues like dry mouth, headache, dizziness, or lightheadedness — and drink according to a plan.
Hydration After Training or Competition
Recovery starts with rehydration. Weighing yourself before and after training is a simple, accurate way to estimate fluid loss. For every pound (0.45 kg) lost, drink about 2.5 cups (20 oz / 600 mL) of fluid. This compensates for both water and electrolytes lost through sweat.
Because voluntary drinking rarely replaces all losses, make hydration a conscious recovery habit. Once you know your sweat rate, you can plan pre-hydration and in-training fluid intake to minimize deficit and reduce post-exercise fatigue.
Within 30 minutes of finishing training, replenish both fluids and carbohydrates to optimize glycogen restoration. Research from the American College of Sports Medicine and International Journal of Sport Nutrition and Exercise Metabolism supports a 4:1 carbohydrate-to-protein ratio for recovery drinks. The carbohydrates replace glycogen used during exercise, while protein supplies amino acids for muscle repair via the mTOR signaling pathway.
Examples include:
Low-fat chocolate milk
Skratch Labs Recovery
Hammer Recoverite
Endurox R4
Ensure, Boost, or Carnation Instant Breakfast
Hydration Status
One of the simplest ways to monitor hydration is urine color. Pale yellow (like lemonade) indicates proper hydration; dark yellow to brown (like apple juice) signals dehydration. The common belief that clear urine equals optimal hydration is a misconception. It may actually indicate overhydration and dilution of electrolytes.
Dehydration decreases plasma volume and cardiac output, reducing blood flow to muscles and skin. This impairs oxygen delivery, increases lactic acid buildup, and elevates core temperature; forcing the body to work harder for the same output. Research from Medicine & Science in Sports & Exercise shows that these physiological changes directly reduce time-to-exhaustion and increase perceived effort.
Caffeine and Alcohol
Caffeine has performance benefits when used strategically, but it’s not ideal for rehydration. It acts as a mild diuretic, increasing urine output and potentially delaying fluid balance restoration if consumed immediately after training. Begin rehydration with non-caffeinated fluids first, then moderate caffeine intake once balance is restored.
Alcohol further increases urine loss and impairs glycogen resynthesis, slowing muscle recovery. Beverages containing 3% alcohol or more interfere with both hydration and protein synthesis, according to research in Journal of Applied Physiology. Save celebratory drinks for after you’ve rehydrated and refueled.
Hydration Tips for Athletes
Plan ahead. Hydration doesn’t happen by accident — make it part of your training strategy.
Drink early. Begin sipping fluids before thirst develops.
Stay consistent. Drink small amounts every 15–20 minutes during exercise.
Cool fluids encourage intake. Aim for ~60°F (15–16°C) to improve palatability and absorption.
Experiment in training. Find the right balance of fluids, electrolytes, and carbohydrates for your body — long before race day.
The Bottom Line
Hydration is one of the simplest, yet most underestimated, tools for peak performance. Every cell, nerve, and muscle in your body depends on fluid balance to function at its best.
When you train, think, and recover with hydration in mind, you’re not just drinking water; you’re fueling performance, precision, and longevity.
Reference Summary
Armstrong, L. E., et al. (1985). Journal of Applied Physiology. Dehydration of just 2% body weight impairs endurance and elevates core temperature.
Maughan, R. J., & Shirreffs, S. M. (2010). Scandinavian Journal of Medicine & Science in Sports. Sodium and carbohydrate co-ingestion improves fluid retention and rehydration.
Sawka, M. N., & Montain, S. J. (2000). Journal of Applied Physiology. Thirst is not a reliable cue during prolonged exercise in heat.
Beelen, M., et al. (2010). International Journal of Sport Nutrition and Exercise Metabolism. The 4:1 carbohydrate-to-protein ratio enhances post-exercise glycogen resynthesis and recovery.
Desbrow, B., et al. (2014). Journal of Applied Physiology. Alcohol impairs rehydration and glycogen restoration.
Shirreffs, S. M., & Sawka, M. N. (2011). Comprehensive Physiology. Human hydration and fluid replacement strategies for performance optimization.