Throwing Science at Gatorade

August, 17, 2005
After yesterday's sports drink discussion, I got an e-mail this morning from Dr. Robert Portman--the pied piper of the new breed of sports drinks. I first met him a few years ago when he was addressing NBA rookies about nutrition. Now he's banging the drum for his company Pacific Health Labs, which makes Accelerade, Endurox R4, and some other products that use this new approach.

Dr. Portman writes that there is more evidence than ever that the new breed of sports drinks, with a little protein, are much better:
Last year Dr. Michael Saunders at James Madison conducted a study that showed that Accelerade compared to Gatorade increased endurance by 29%, decreased muscle damage an amazing 83% and increased endurance in a subsequent exercise bout by 40%. Now, Dr. John Seifert from St. Cloud University is presenting the results of a truly landmark study. In this study, Dr. Seifert exercised athletes until they lost 2.5% of their body weight and then rehydrated them with Accelerade, Gatorade or water. Accelerade was 15% better than Gatorade and 40% better than water. With this latest study, research has now shown that Accelerade is more effective than a conventional carbohydrate sports drink, such as Gatorade, in improving rehydration, extending endurance, reducing muscle damage and extending endurance in a subsequent exercise bout.

I don't want to just tell one side of the story here. If anyone from Gatorade or anywhere else has a dissenting opinion, by all means comment away or e-mail me and I'll be happy to keep the debate going.

For anyone who understands the language of science, here are the abstracts of three relevant studies Dr. Portman sent along. (There are lots more studies here.)Effects of a Carbohydrate-Protein Beverage on Cycling Endurance and Muscle Damage
School of Kinesiology and Recreation Studies, James Madison University, Harrisonburg, VA

SAUNDERS, M. J., M. D. KANE, and M. K. TODD. Effects of a Carbohydrate-Protein Beverage on Cycling Endurance and Muscle Damage. Med. Sci. Sports Exerc., Vol. 36, No. 7, pp. 1233"1238, 2004. Introduction: The purpose of this study was to determine whether endurance cycling performance and postexercise muscle damage were altered when consuming a carbohydrate and protein beverage (CHOP; 7.3% and 1.8% concentrations) versus a carbohydrate-only (CHO; 7.3%) beverage. Methods: Fifteen male cyclists (mean V˙ O2peak  52.6  10.3 mL·kg1·min1) rode a cycle ergometer at 75% V˙ O2peak to volitional exhaustion, followed 12"15 h later by a second ride to exhaustion at 85% V˙ O2peak. Subjects consumed 1.8 mL·kg1 BW of randomly assigned CHO or CHOP beverage every 15 min of exercise, and 10 mL·kg1 BW immediately after exercise. Beverages were matched for carbohydrate content, resulting in 20% lower total caloric content per administration of CHO beverage. Subjects were blinded to treatment beverage and repeated the same protocol seven to 14 d later with the other beverage. Results: In the first ride (75% V˙ O2peak), subjects rode 29% longer (P 0.05) when consuming the CHOP beverage (106.3 45.2 min) than the CHO beverage (82.3  32.6 min). In the second ride (85% V˙ O2peak), subjects performed 40% longer when consuming the CHOP beverage (43.6  12.5 min) than when consuming the CHO beverage (31.2  8.7 min). Peak postexercise plasma CPK levels, indicative of muscle damage, were 83% lower after the CHOP trial (216.3  122.0 U·L1) than the CHO trial (1318.1  1935.6 U·L1). There were no significant differences in exercising levels of V˙ O2, ventilation, heart rate, RPE, blood glucose, or blood lactate between treatments in either trial. Conclusion: A carbohydrate beverage with additional protein calories produced significant improvements in time to fatigue and reductions in muscle damage in endurance athletes. Further research is necessary to determine whether these effects were the result of higher total caloric content of the CHOP beverage or due to specific protein-mediated mechanisms. Key Words: CYCLING, RECOVERY, SUBSTRATE UTILIZATION, SPORTS DRINKS

Fluid Retention Properties of Carbohydrate/Protein and Carbohydrate-Only Sports Drinks
Seifert John G, Harmon Joseph, DeClercq Patti
Human Performance Laboratory, St Cloud State University, St Cloud, MN USA

Nose et al. (1988) reported that beverage osmolality, and ultimately serum osmolality, is one of the key factors in determining fluid retention rates during rehydration. Previous investigations have focused on the role of carbohydrate and sodium to aid fluid retention during rehydration. Makers of sports drinks tout their products as better fluid replacement beverages than plain water because of the combination of water, carbohydrate, and sodium. However, other compounds may also influence osmolality, and ultimately, fluid retention. The purpose of this study was to compare two popular sports drinks, a carbohydrate + protein and a carbohydrate-only beverages, and water in fluid retention following 2% BW loss.

Following approval from the IRB, data collection began with 13 subjects. Subjects cycled at 25C to dehydrate to 2% of starting BW during three trials. They then ingested a fluid, within 20 minutes, at a volume equal to BW loss. Subjects ingested a 6% CHO + 1.5% protein + 24 mEq/kg sodium sports drink (CP, Accelerade', PacificHealth Labs), a 6% CHO + 20 mEq/kg sports drink (CHO, Gatorade', PepsiCo), or plain water (WA) during a three hour recovery period. Average beverage osmolality for CP was 305 mOsm/kg water, 285 mOsm/kg for CHO, and 4 mOsm/kg for WA. Blood samples, urine samples and volume, and BW were measured at seven time points during each trial.

Subjects averaged 1.74 kg weight loss (2.5 +.06 %) from exercise. Fluid retention was significantly (p=.000) greater for CP (88 +1.3%) than CHO (75 +4%) and WP (53 +4.5%). Average serum osmolality was greater (p=.000) for CP (284.7 +1.4 mOsm/kg) than CHO (282.6 +1.4 mOsm/kg) and WA (280.6 +1.7 mOsm/kg). Consequently, average urine osmolality was also greater (p=.001) for CP (569.4 +43.5 mOsm/kg) than CHO (472.9 +31 mOsm/kg) and WA (303.7 +42 mOsm/kg). Serum protein was lower for CP (7.39 +.3 g/L) and CHO (7.33 +.2 g/L) than WA (7.63 +.2 g/L).

Results indicate that a CP may be a preferable choice when fluid retention is a concern. Fluid retention for CP was 15% greater than CHO and 40% greater than WA. It is apparent that CP maintained a slightly higher serum osmolality during fluid replacement that resulted in fluid retention being improved over CHO and WA during a three-hour recovery period. It is not possible, however, to discern if it was the protein, sodium, or combination that added to the osmolality that significantly increased fluid retention with CP compared to CHO. Plain water ingestion, however, led to a significant dilution of the serum that resulted in only 53% fluid retention.

Nose H et al. (1988). J Appl Physiol 65:325-31.

Effects Of A Carbohydrate/Protein Gel On Exercise Performance In Male And Female Cyclists

Saunders, MJ, Herrick, JE, Luden, ND, Hart, JE, Mishler, AE, Moore, RW
Human Performance Laboratory, James Madison University, Harrisonburg, Virginia, USA

The two purposes of this study were to: 1) determine if consumption of a carbohydrate/protein sports gel (CHO+P) improved endurance performance compared to a carbohydrate-only gel (CHO), and 2) determine if the putative benefits of CHO+P treatments, which have previously been demonstrated only in males, are similar between genders.

Thirteen recreationally competitive male (8) and female (5) cyclists (VO2peak = 57.9±7.0 ml/kg/min) completed two timed trials (CHO and CHO+P) to volitional exhaustion on an electrically-braked cycle ergometer at 75% of VO2peak. At 15-minute intervals throughout these rides, subjects received a CHO gel (Gu Energy Gel®, Gu Sports) or CHO+P gel (AccelGelTM, PacificHealth Laboratories, Inc.), which were matched for carbohydrate content (CHO = .15gCHO per kgBW; CHO+P = .15gCHO + .038g protein per kgBW). Trials were performed using a randomly counterbalanced, double-blind design.

No differences between CHO and CHO+P trials, respectively, were observed for VO2 (3.0±0.65; 3.0±0.63 L/min), heart rate (159.5±12.7; 156.5±14.8 bt/min), RER (.97±.03; .96±.04), blood lactate (3.7±1.4; 2.9±1.5 mmol/L), blood glucose (75.2±14.0; 79.0±14.9 mg/dl) or ratings of perceived exertion (13.9±1.8; 13.9±1.8), which were obtained following 30 minutes of riding. However, subjects rode 13% longer (p<.05) when utilizing the CHO+P gel (116.6±28.5 min) than the CHO gel (102.8±25.0 min). In addition, males (101.8±24.6; 114.8±26.2) and females (104.4±28.6; 119.6±34.9) demonstrated very similar responses to the CHO and CHO+P trials, respectively, with no significant treatment-by-gender effect (p=.829).

These findings demonstrate that CHO+P gels provide significant performance advantages over CHO gels, as similarly demonstrated in studies using CHO+P beverages. In addition, this data demonstrates that females respond very similarly to males with regards to their responses to CHO+P treatments.



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