by Elyse Lovett, Move Nutrition Editor
Why Hydration Matters in Sports Nutrition
As consumers we hear every day drink more water, stay hydrated, get more electrolytes, and balance your nutrient intake. Day after day, we try to fuel our bodies with the necessary fluids our body needs – thinking at the end of the day – is still wasn’t enough. Insert athletes and the stakes become higher. With intense training schedules and elevated sweat rates, athletes lose far more than just water, they lose critical electrolytes and nutrients that keep their muscle firing, minds sharp, and their bodies functioning at peak performance. For athletes, hydration is not just a recommendation, it is a performance strategy and may be the difference of hitting a personal best or falling short.
We know hydration is foundational, and it has been proven through research time after time that even mild hydration can impair cognitive function, slow reaction times, reduce strength and power, and increased perceived exertion. Athletes who are underhydrated feel like they are working harder and performing worse- and more often than not, they are.
Hydration research goes back far, dating back to more than 50 years. Early studies focused on basic fluid loss and understanding sweat rates. By the late 90s, research had evolved to examine hydrations direct impact on athletic outcomes – highlighting its influences on strength, power output, recovery, and time to exhausting. In the following decades, studies began to explore the cognitive effects of dehydration and the effects on mental performance as it relates to memory, attention, and reaction times.
Today, the science is more advance than ever. We are seeing a shift toward precision hydration, recognizing that athletes have highly individualized needs based on body size, sweat composition and training intensity. New research is looking at functional hydration ingredients that go beyond basic fluid replacement to enhance nutrient uptake and absorption and performance outcomes. In addition, wearable hydration sensors, AI tools, and real-time tracking has enabled for a more targeted personalized approach toward hydration, not just for athletes but for active lifestyle users as well.
Key Research Through the Years
1970s – 1980s
2% Dehydration Impairs Performance
1990s – 2000s
Hydration Improves Endurance & Recovery
2000s – 2010s
Cognitive Performance Is Hydration-Dependent
2000s – Present
Electrolyte Balance Is Critical
2020s – Present
Novel Ingredients Can Enhance Rehydration
Key Research Through the Years
1970s – 1980s
2% Dehydration Impairs Performance
1990s – 2000s
Hydration Improves Endurance & Recovery
2000s – 2010s
Cognitive Performance Is Hydration-Dependent
2000s – Present
Electrolyte Balance Is Critical
2020s – Present
Novel Ingredients Can Enhance Rehydration
The Impact of Dehydration on Athletic Performance
Our favorite compound H2O – water – is essential for just about every physiological process in the body. For the average person, hydration depends on internal factors such as age, weight, gender and external factors such as excise intensity and environmental conditions. For athletes, fluid loss through sweat can rapidly deplete water levels and lead to dehydration – often not even recognized before thirst is perceived. Let’s do a quick review of the different ways dehydration effects athletic performance:
During exercise, fluid loss through sweat can reduce blood volume, causing a decrease in the amount of blood pumped by the heart. As a result, heart rate increases to maintain cardiac output. In a well-hydrated state, the body regulates temperature through vasodilation and sweat – dehydration counters this balance. Studies have shown that fluid restriction is associated with an increase in core temperature, as a result negatively influences performance and care should be taken to ensure proper hydration.[1]
Thermoregulation is another critical area impacted by hydration – with less fluid available for sweating and reduced blood flow to the skin – the body’s ability to cool itself decreases. When core temperature rises quickly, there is an increase in heat cramps, exhausting, and heat stroke. This can shorten the time an athlete can effectively train or compete especially in high-heat conditions.
Electrolytes are essential for muscle contraction and nerve impulse transmission – dehydration paired with electrolyte imbalances can impair neuromuscular function. Maintaining proper hydration and electrolyte balance before, during, and after training will help reduce fluid loss, maintain performance, maintain plasma volume and reduce heat stress.[2]
Cognitive function is essential in many sports that rely on decision-making and reaction time. We are learning more about the connection of cognitive function and athletic performance from a wide variety of scientific research. As cognition related to dehydration, numerous studied have shown dehydration slowed reaction times, decreased concentration, and increased mental fatigue.[3]
Dehydration on athletic performance has been well-documented in athletes for many years. New research is diving into areas of precision hydration that are tailored to individual sweat rates and compositions, as well as the role of novel rehydration solutions that go beyond water and electrolytes to include functional ingredients for fluid retention and metabolic support.
New Research Driving the Hydration Category
Electrolyte Research Continues
Exercise-associated muscle cramps (EAMC) are a common issue for endurance athletes which can impact training and performance. Electrolyte imbalance and dehydration are leading theories behind EAMC – yet most sports drink do not include magnesium, a key mineral for muscle contraction and relaxation, in their formulations. A 2022 study surveyed athletes at two identical half marathons who hydrated with either MAGNAK (a magnesium-rich electrolyte mix) or water. The post-race questionnaire focused on the incidence and severity of muscle cramps. The results showed that hydration with MAGNAK reduced overall cramp incidence by 54% and significantly lowered both mild and severed cramps compared to water alone. The study suggests that including 100mg magnesium per serving in electrolyte beverages could be an effective strategy to improve athletic performance.[4]
Personalized Hydration Strategies
Hydration strategies are often one-size fit-all, but athletes have highly individualized sweat rates and sodium losses especially during intense training or competition in high-heat environments. A recent randomized crossover study investigated whether personalized hydration strategies (PHS) tailored to individual sweat rates and sodium loss could improve fluid balance and exercise performance under both normothermic and hyperthermic conditions. Results showed that PHS significantly improved fluid intake, reduced body mass loss, and delivered sodium levels aligned with individual needs. In hot conditions – PHS reduced thirst perception and extended high-intensity internal exercise time by 40% compared to the control.[5]
Electrolyte Balance and High-Heat
Exercising in high-heat environments significantly increases sweat loss and electrolyte depletion. Sodium, chloride, and potassium are essential for maintaining fluid balance and thermoregulation. A recent narrative review examined how electrolyte concentration in sweat changed following heat training. The review found the heat acclimation consistently reduces sweat sodium and chloride concentration but self-directed heat acclimatization in mild temperatures often fails to trigger these adaptations.[6]
Functional Ingredients & Novel Theories
Several functional ingredients play key roles in hydration and athletic performance. Glycerol acts as a potent osmolyte, promoting hyperhydration and helping delay dehydration during prolonged or high-high exercise. Betaine supports cellular hydration while contributing to power output and endurance capacity. Taurine, a naturally occurring amino acid derivative supports electrolyte balance with studies indicating improved time to exhausting when used in hydration formulas. Carbohydrates like glucose and fructose remain foundational. Glucose enhances sodium and water uptakes, while a 2:1 glucose-to-fructose blend optimizes fuel availability especially during high intensity endurance efforts.
One area that is getting more attention is ingredients that enhance blood flow and thermoregulation, helping athletes stay cool and perform longer in heat-stressed environments. Ingredients such as L-citrulline and beetroot extract, known for their nitric oxide boosting effect, improve oxygen delivery and vasodilatation which may help with endurance and temperature regulation.
Cognitive function is another area gaining traction within the hydration space. Combining ingredients such as L-theanine with natural caffeine sources for a more sustained focus – making it idea for long-duration exercise. Taurine, Rhodiola and other adaptogens such as Ashwagandha offer mental and physical stress support which can have benefits in high-stress athletic performing competitions.
Plant bioactives such as quercetin are showing promising results supporting hydration and recovery – though more work is needed for optimal dosing and time. Functional dairy fractions such as milk permeate are emerging as innovative hydration matrices that may improve fluid retention with fewer GI issues. Smart wearables could soon enable real-time, personalized hydration strategies based on individual needs. Combining BCAA’s with electrolytes appears effective for addressing symptoms like cramping, even if not directly enhancing performance status. Finally, the additional use of amino acids to support metabolic recovery signals a shift in hydration science- moving beyond basic fluid and electrolyte replacement to more holistic performance support.
Functional ingredients and emerging technologies have led the way for precision-based performance hydration – an approach that recognizes individual needs. By integrating targeted nutrients for fluid balance, electrolyte replenishment, and cognitive health, hydration strategies can be tailored to an athlete’s unique physiology, training demands, and environmental conditions.
Summary
Hydration science in sports and active nutrition has come a long way from basic fluid replacement and sweat rates to a precision-based, performance-optimizing strategy. What was what we simply called “drink more water” evolved into an approach that incorporates individual sweat rates, advance electrolyte formulations, and functional ingredients to support not just hydration but endurance, recovery, thermoregulation, and cognitive performance.
Subscribe for additional Move Nutrition Quarterly content like research updates, market insights, and more.