Abstract
bjectives: The purpose of this study was to examine the acute effects of branched-chain amino acids (BCAAs)-containing electrolyte beverage (AE) on water–electrolyte balance, muscle damage, time to finish the final 5 km, and muscle strength compared to a standard commercially available carbohydrate–electrolyte sports beverage (CE), pure water (W), and no rehydration (N). Methods: Fourteen trained male participants (20±2 years old) completed four randomized 21 km running trials. The participants were instructed to consume their drink (150 mL W, 150 mL CE, or 150 mL AE) or no rehydration (N) at 5 km, 10 km, and 15 km. Body mass and muscle strength were assessed, and blood samples were collected before and after exercise. Perceptual scales were administered during and after running. Blood electrolyte levels (sodium, potassium, and chloride) and creatine kinase (CK) concentration were analyzed. Results: The change in plasma volume with AE was significantly smaller than that with N (p< 0.05). Consuming AE maintained the best potassium balance (p< 0.05). Twenty-four hours after exercise, serum CK concentrations significantly elevated in N, W, and CE (p< 0.05),
during and after running. Blood electrolyte levels (sodium, potassium, and chloride) and creatine kinase (CK) concentration were analyzed. Results: The change in plasma volume with AE was significantly smaller than that with N (p< 0.05). Consuming AE maintained the best potassium balance (p< 0.05). Twenty-four hours after exercise, serum CK concentrations significantly elevated in N, W, and CE (p< 0.05), but did not reach statistical significance in the AE group (p> 0.05). Compared to N, consuming AE resulted in significantly less soreness 24 h after exercise (p< 0.05). There was no difference in time to finish the final 5 km (p> 0.05). Maximal voluntary isometric force output was significantly lower after exercise with N and W (p< 0.05) but not with CE or AE (p> 0.05). Conclusions: Consuming a BCAAs-containing sports beverage during a 21 km run can help reduce dehydration, maintain potassium balance, lower muscle damage, and prevent the decline in lower limb strength after 21 km running. Keywords:hydration status; electrolyte balance; branched-chain amino acids; endurance exercise performance 1. Background Long-distance running events, such as full and half marathons, are popular world- wide, attracting athletes of all levels. During extended periods of high-intensity exercise, the body loses large amounts of fluids and electrolytes through sweat, resulting in a signifi- cant decrease in body weight, which is a clear indication of dehydration [1]. Dehydration not only impairs athletic performance but also poses several health risks, including elec- trolyte imbalances, muscle cramps, and increased fatigue [2,3]. Sports drinks, typically carbohydrate–electrolyte beverages, have long been a key strategy for replenishing fluids and electrolytes lost during exercise [4]. Electrolytes, such as sodium, potassium, and chloride, play an essential role in regulating fluid balance within extracellular and intracel- lular fluid compartments and are crucial for preventing exercise-associated muscle cramps Nutrients2024,16, 3799.
Nutrients2024,16, 3799 2 of 17 and maintaining optimal cell function [5]. Therefore, appropriate supplementation during exercise is crucial. Proper supplementation helps maintain water–electrolyte balance and reduce muscle damage. In recent years, some sports electrolyte beverages have incorporated amino acids into their formulations [6], and it is reported that amino acids can enhance fluidreplacement [ Fur- thermore, the repetitive strain from running can lead to varying degrees of exercise-induced muscle damage, which may exacerbate fatigue and hinderrecovery [9–11]. Branched- chain amino acids (BCAAs), which include leucine, isoleucine, and valine, are well known for their roles in muscle protein synthesis and reducing muscle damage and post-exercise soreness [12,13]. The incorporation of BCAAs into sports beverages has emerged as a promising innovation. However, there is not unanimous agreement among studies re- garding their effectiveness in enhancing performance or reducing muscle damage [14,15], particularly when BCAAs were incorporated as an ingredient in sports drinks, as their impact is not well defined. Additionally, BCAAs, especially leucine, have a naturally bitter taste, which can negatively impact the flavor profile of sports drinks [16]. Owing to constraints in flavor profile and solubility, sports beverages can only incorporate minimal quantities of BCAAs. For BCAAs to exert noticeable effects, a certain dosage must be achieved, but the minimum effective dose of BCAAs is not clear [13]. Given that the practical application effects of BCAAs as an ingredient in sports drinks remain controversial, this study aims to investigate the effects of a novel sports beverage with BCAAs on hydration status, electrolyte balance, muscle damage, and performance, compared to a traditional carbohydrate–electrolyte drink and pure water. We hypothesized that the consumption of this beverage during running can help maintain water–electrolyte balance and reduce muscle damage. 2. Methods 2.1. Participants and Ethical Approval This study was conducted with prior review and approval from the Sports Science Experiment Ethics Committee of Beijing Sports University (No. 2024079H). Young male adults with endurance training experience were recruited from the uni- versity, meeting the following criteria: (1) aged 18–25 years old; (2) a normal BMI range (18.5–24.9); (3) engaged in endurance training for more than 8
Approval This study was conducted with prior review and approval from the Sports Science Experiment Ethics Committee of Beijing Sports University (No. 2024079H). Young male adults with endurance training experience were recruited from the uni- versity, meeting the following criteria: (1) aged 18–25 years old; (2) a normal BMI range (18.5–24.9); (3) engaged in endurance training for more than 8 h per week; (4) healthy individuals without clinically diagnosed diseases; (5) no smoking, alcohol abuse, or other unhealthy habits; (6) had not participated in any clinical or nutritional research trials within the last month; (7) not participating in other sports or nutritional intervention experiments during the study; and (8) willing to follow the experimental procedures voluntarily. A total of 15 subjects who met the requirements were enrolled. Participant characteristics are presented in Table. Fourteen male participants com- pleted all trials. During the experiment, one subject did not complete all trials due to an ankle injury, and, finally, 14 subjects completed all the experimental procedures. Table 1.Participant characteristics. Variable Mean ±SD Age (years) 22 ±2 Height (cm) 176.6 ±3.6 Body mass (kg) 67.2 ±6.5 Body fat (%) 15.1 ±3.8 VO 2max (mL O 2/kg/min) 55.2 ±4.0 2.2. Experimental Design This is a clinical trial that is a randomized, controlled, crossover design. The timeline and testing procedures for each visit are illustrated in Figure detail below. Initially, the volunteers underwent baseline assessments. These assessments
Nutrients2024,16, 3799 3 of 17 included measurements of height, weight, and body composition, as well as a cardiopul- monary exercise test (CPET) to determine the maximum oxygen consumption (VO2max). This test established the speed at which they would perform the 21 km treadmill tests.Nutrients 2024, 16, 3799 4 of 17 humidity of 35 ± 5 %. Participants were asked to maintain consistent clothing for each running session. Rehydration was scheduled at 5 km, 10 km, and 15 km to simulate an actual half- marathon race. The participants were instructed to consume their drink (150 mL W, 150 mL CE, or 150 mL AE) or no rehydration (N) at 5 km, 10 km, and 15 km. Participants’ ratings of perceived exertion (RPE), thirst, and gut comfort were recorded every 15 mins. The sweat patch (Tegaderm + Pad, 3M, St. Paul, MN, USA) was placed on the forearm to collect sweat samples during the race. Real-time heart rates were also tracked using chest strap heart rate monitors (Polar; Kempele, Oulu, Finland). Immediately following the completion of the 21 km running, participants underwent post-exercise testing, including blood markers, nude body weight, perceptual scales, and lower limb strength assessment. The timeline and each test can be visualized in Figure 1. The blood sample was taken and muscle soreness was assessed 24 h after exercise. The four treadmill tests were conducted in a random order, with participants either consuming a different randomized drink (W, CE, or AE) or not rehydrating. There was a one-week washout period between each ex- periment. Figure 1. Study design. Abbreviations: USG, urine specific gravity; N, no rehydration during run- ning; W, consuming pure water during running; CE, consuming a standard carbohydrate–electro- lyte sports beverage during running; AE, consuming a branched-chain amino acids (BCAAs)-con- taining electrolyte beverage during running. 2.3. Specific Testing Procedures 2.3.1. VO2max Assessment VO2max was assessed following the methodology outlined in previous studies [19], and the corresponding speeds for different VO2max intensities were calculated. The VO2max tests were conducted on a running treadmill (h/p/cosmos Mercury 4.0, Germany) using a gas exchange analysis system (MetaMax-3B; CORTEX Biophysik GmbH, Leipzig,
amino acids (BCAAs)-con- taining electrolyte beverage during running. 2.3. Specific Testing Procedures 2.3.1. VO2max Assessment VO2max was assessed following the methodology outlined in previous studies [19], and the corresponding speeds for different VO2max intensities were calculated. The VO2max tests were conducted on a running treadmill (h/p/cosmos Mercury 4.0, Germany) using a gas exchange analysis system (MetaMax-3B; CORTEX Biophysik GmbH, Leipzig, Germany). The subjects began with a 5 min warm-up at a speed of 8.0 km/h. After completing the warm-up, the subjects started at a speed of 9.6 km/h for the first minute. The speed was then increased by 1.6 km/h every minute, up to a speed of 17.6 km/h. Once the speed exceeded 17.6 km/h, it was increased by 0.8 km/h every minute until the subjects were considered to have reached their maximum oxygen uptake. The treadmill incline was con- sistently maintained at 1%. Figure 1.Study design. Abbreviations: USG, urine specific gravity; N, no rehydration during running; W, consuming pure water during running; CE, consuming a standard carbohydrate–electrolyte sports beverage during running; AE, consuming a branched-chain amino acids (BCAAs)-containing electrolyte beverage during running. All participants were instructed to avoid consuming alcoholic or caffeinated drinks and to refrain from engaging in intense physical activities for 24 h prior to the trials. They were also asked to keep a food diary for 24 h before the first trial and to replicate their meals before each of the subsequent trials. The experimental protocols used an electrolyte beverage fortified with BCAAs (AE, Alienergy Electrolyte Drink Professional Edition; Chi Forest, Beijing, China), a standard commercially available carbohydrate–electrolyte sports beverage (CE, GATORADE ® Thirst Quencher; PepsiCo, Purchase, NY, USA) and pure water (W). Additionally, please see Table Table 2.AE and CE contents. Amount per 100 mL AE CE Calories (kJ) 85 102 Total carbohydrate (g) 4.7 6.0 Total protein (mg) 287 0 Peptide (mg) 67 0 BCAAs (mg) 220 0 Sodium (mg) 52 45 Potassium (mg) 39 5–25 Calcium (mg) 12 0 Magnesium (mg) 5 0 Niacin (mg) 0.6 0 Vitamin E (mgα-TE) 0.3 0 Vitamin B6 (mg) 0.06 0 We implemented substantial measures to ensure
AE CE Calories (kJ) 85 102 Total carbohydrate (g) 4.7 6.0 Total protein (mg) 287 0 Peptide (mg) 67 0 BCAAs (mg) 220 0 Sodium (mg) 52 45 Potassium (mg) 39 5–25 Calcium (mg) 12 0 Magnesium (mg) 5 0 Niacin (mg) 0.6 0 Vitamin E (mgα-TE) 0.3 0 Vitamin B6 (mg) 0.06 0 We implemented substantial measures to ensure double blinding throughout the trial. These measures included the following: (a) a designated researcher responsible for labeling and dispensing the drinks using opaque squeeze bottles; (b) participants were not informed
Nutrients2024,16, 3799 4 of 17 about the composition of the liquids they consumed and could not differentiate between AE and CE based on taste; (c) each dispensed drink was assigned a random number, and during statistical analysis, the researchers did not know which number corresponded to which hydration strategy. The 21 km treadmill test took place in the morning (08:00–10:00). Participants’ vis- its were scheduled to be at the same time of day (±1 h) for each visit. Each subject’s urine sample (first urine of the day) was collected to check their urine specific gravity (USG) using a portable refractometer (PAL-10S; ATAGO, Tokyo, Japan). Participants with USG values≤1.025 were considered at a normal hydration state [17]. The participants had a standardized breakfast and drank 500 mL of water approximately 1.5 h before the experimental trials. Fifteen to thirty minutes before the race, they completed a standardized warm-up routine and ensured that they had urinated. Then, pre-exercise testing was completed, which included blood collection, nude body weight measurement, and lower limb strength assessment. Next, the 21 km treadmill test was conducted. Participants were required to run at a speed equivalent to 65% of their VO2max intensity for the first 16 km of the test.They were asked to complete the last 5 km as fast as possible and were allowed to change the treadmill speed at any time. The treadmill (Mercury 4.0, h/p/cosmos, Cologne, Germany) slope was maintained at 1% [18]. The tests were carried out in a controlled room in the morning, with a temperature of 23±1 ◦ C and a relative humidity of 35±5%. Participants were asked to maintain consistent clothing for each running session. Rehydration was scheduled at 5 km, 10 km, and 15 km to simulate an actual half- marathon race. The participants were instructed to consume their drink (150 mL W, 150 mL CE, or 150 mL AE) or no rehydration (N) at 5 km, 10 km, and 15 km. Participants’ ratings of perceived exertion (RPE), thirst, and gut comfort were recorded every 15 mins. The sweat patch (Tegaderm + Pad, 3M, St. Paul, MN, USA) was
half- marathon race. The participants were instructed to consume their drink (150 mL W, 150 mL CE, or 150 mL AE) or no rehydration (N) at 5 km, 10 km, and 15 km. Participants’ ratings of perceived exertion (RPE), thirst, and gut comfort were recorded every 15 mins. The sweat patch (Tegaderm + Pad, 3M, St. Paul, MN, USA) was placed on the forearm to collect sweat samples during the race. Real-time heart rates were also tracked using chest strap heart rate monitors (Polar; Kempele, Oulu, Finland). Immediately following the completion of the 21 km running, participants underwent post-exercise testing, including blood markers, nude body weight, perceptual scales, and lower limb strength assessment. The timeline and each test can be visualized in Figure. The blood sample was taken and muscle soreness was assessed 24 h after exercise. The four treadmill tests were conducted in a random order, with participants either consuming a different randomized drink (W, CE, or AE) or not rehydrating. There was a one-week washout period between each experiment. 2.3. Specific Testing Procedures 2.3.1. VO2max Assessment VO2max was assessed following the methodology outlined in previous studies [19], and the corresponding speeds for different VO2max intensities were calculated. The VO2max tests were conducted on a running treadmill (h/p/cosmos Mercury 4.0,Germany) using a gas exchange analysis system (MetaMax-3B; CORTEX Biophysik GmbH, Leipzig, Germany). The subjects began with a 5 min warm-up at a speed of 8.0 km/h. After completing the warm-up, the subjects started at a speed of 9.6 km/h for the first minute. The speed was then increased by 1.6 km/h every minute, up to a speed of 17.6 km/h. Once the speed exceeded 17.6 km/h, it was increased by 0.8 km/h every minute until the subjects were considered to have reached their maximum oxygen uptake. The treadmill incline was consistently maintained at 1%. 2.3.2. Nude Body Mass Assessment Participants were weighed nude using an electronic scale (accurate to 0.001 g) before and after exercise. They were instructed to remove their clothing, dry off any sweat, and empty their bladder. Whole-body fluid loss was calculated from the reduction in
to have reached their maximum oxygen uptake. The treadmill incline was consistently maintained at 1%. 2.3.2. Nude Body Mass Assessment Participants were weighed nude using an electronic scale (accurate to 0.001 g) before and after exercise. They were instructed to remove their clothing, dry off any sweat, and empty their bladder. Whole-body fluid loss was calculated from the reduction in body mass that occurred during the trial. Sweat loss was estimated by accounting for the reduction in
Nutrients2024,16, 3799 5 of 17 body mass and fluid intake. Any reductions in mass due to respiratory water loss or carbon loss as carbon dioxide was assumed to be negligible and consistent across trials [20]. 2.3.3. Measurement of Blood Markers Hemoglobin and hematocrit were assessed by a 3-part Differential Hematology Ana- lyzer (KX-21N; Sysmex, Kobe, Japan), and these values were used to calculate the percent change in plasma volume (%∆PV) [21]. Two blood samples were centrifuged for 15 min at 3500 RPM at 4 ◦ C to obtain plasma samples and serum samples. Plasma osmolality (POSM) was analyzed through freezing point determination (OSMOMAT 3000; Gonotec, Berlin, Germany). Serum sodium (Na + ), potassium (K + ), and chlorine (Cl − ) were assessed by an Electrolyte Analyzer (Easy Lyte Plus; MEDICA, Minnetonka, MN, USA). Creatine kinase (CK) was measured with a fully automatic immunoanalyzer (Beckman DXC 800, Beckman Coulter, Fullerton, CA, USA). 2.3.4. Sweat Collection and Samples Analysis The skin at the respective sites was shaved prior to the run. Upon completing the 10 km run, the skin of the participant’s forearm was cleaned with alcohol and pure water and the sweat patch (Tegaderm + Pad, 3M, St. Paul, MN, USA) was placed on the left dorsal forearm to collect sweat samples during the race. Patches were removed from the skin upon moderate sweat absorption (~0.5 g), but prior to saturation, as determined by visual inspection [22]. Upon removal, the absorbent pad was immediately separated from the Tegaderm™using clean forceps and placed in an air-tight plastic tube. The sweat was separated from the patches by centrifugation. Sweat sodium (Na + ), potassium (K + ), and chlorine (Cl − ) were assessed by an Electrolyte Analyzer (Easy Lyte Plus; MEDICA, Minnetonka, MN, USA). The regression equations developed by Baker et al. [22] were used to subtract the background mmol/L of electrolytes in the absorbent patches. Whole-body sweat Na + , K + , and Cl − were predicted from the dorsal forearm through the prediction models developed by Baker et al. [22,23]. Electrolyte balance was calculated by subtracting the amount
Minnetonka, MN, USA). The regression equations developed by Baker et al. [22] were used to subtract the background mmol/L of electrolytes in the absorbent patches. Whole-body sweat Na + , K + , and Cl − were predicted from the dorsal forearm through the prediction models developed by Baker et al. [22,23]. Electrolyte balance was calculated by subtracting the amount of electrolyte lost through sweat from the amount ingested. Negative values in fluid and electrolyte balance indicate deficits. These calculations assumed that sweat rate and sweat electrolyte concentration remained constant throughout the race, although slight variations likely occurred [24]. 2.3.5. 5 km Time Trials After completing 16 km, participants were allowed to adjust the treadmill speed to complete the final 5 km as quickly as possible. The time taken to complete this segment was recorded. 2.3.6. Lower Limb Strength Assessment Participants performed three countermovement vertical jumps for maximal height on a vertical jump measurement device (GMCS-IV; Beijing Sport University Sports Engineering Research Center, Beijing, China) to assess pre-race and post-race jump height with their hands placed on their hips. The highest jump was used for statistical analysis. Participants familiarized themselves with the jump test beforehand. Maximal voluntary isometric contraction (MVIC) of the quadriceps was assessed using a versatile knee extension device (David F-200; David GmbH, Neu-Ulm, Germany), equipped with a digital analysis module (MC-M; DAVID GmbH, Neu-Ulm, Germany) that recorded real-time and peak torque during isometric muscle contractions. Participants adjusted the seat height to ensure proper positioning, which aided in optimal muscle exertion. A strap across the waist secured the subjects to maintain a consistent trunk-thigh angle of 120 ◦ and a knee joint angle of 120 ◦ . The lever arm’s rotation axis aligned with the lateral femoral epicondyle of the participant’s right leg, and the participants adjusted the position of the lever arms. The seat height and lever arm positions were recorded to ensure consistency across all subsequent tests. Participants performed three 3 s maximal voluntary
Description
This study investigates the effects of a BCAAs-containing sports beverage on hydration and muscle recovery during a 21 km run.