Effect of Sports Drinks on Athletic Endurance



Comparison of Water Versus Gatorade Hydration on VO2max and Maximal Exercise Time in Athletes

Brennan Buchan and Kristin Fiore

Department of Biological Science

Saddleback College

Mission Viejo, CA 92692

Abstract

Dehydration is caused by excessive sweating and loss of water during exercise. It is vital for athletes to replenish the water and electrolytes lost through sweat in order to avoid low blood pressure and plasma volume, which leads to elevated heart and respiration rates, low endurance, and overheating. Sports drinks such as Gatorade, not only replenish lost water, but also provide electrolytes and carbohydrates to athletes. It was predicted, however, that there would be no difference between VO2max (ml/kg/min) and maximal exercise time (seconds) of athletes when hydrating with water versus Gatorade for a short, sustained period of time. After having 5 male athletes, who exercise regularly, bike for a short duration no significant difference was found (p=0.911) between their VO2max with water hydration (2588.2(270.2) versus Gatorade (2639.6(351.4). Also, no significant difference was found (p=0.311) between the maximal exercise time (sprint time) with water (21.6(7.6) versus Gatorade (31.8(5.4) hydration.

Introduction

Gatorade is used by many athletes to increase stamina when exercising, under the impression that it will produce better results than water. Hydration is necessary with any kind of exercise. Proper hydration and nutrients increase endurance, lower sub-maximal exercise heart rate, and reduce fluid loss (Duvillard et al, 2004).  The heat produced by working muscles exceeds the heat released by the body causing overall body temperature to rise when exercising. This increase in temperature causes an increase in sweating and blood flow to the skin, and as a result, heat is removed by the evaporation of sweat from the skin, radiated from the body to the cooler surroundings, and is lost by convection to moving air. A heavy sweater can potentially lose more than 2.84 liters of sweat during each hour of exercise, meaning dehydration can develop very quickly (Bergerson, 2006). Due to this need for effective hydration, athletic drinks contain carbohydrates and electrolytes that should re-hydrate the body more effectively than water.  Sports drinks such as Gatorade also contain sodium, which helps promote responsive muscle contraction and the necessary water retention (Smith, 1992). Smith’s study (1992) states that Gatorade has ingredients to quench thirst and replenish lost electrolytes, which aids in athletic endurance and fluid retention, making it a logical choice for hydrating before and during exercise.

VO2max is the maximum ability of an individual’s body to utilize oxygen during maximal exercise. It is commonly used to determine the endurance of athletes and their relative fitness. By comparing both the level of VO2max an athlete achieves and how long they can maintain it, that athlete’s fitness and endurance can be easily studied.

The objective of this study is to determine how an athlete’s endurance level, as illustrated by VO2max and their time at maximal exercise, is affected by drinking water versus drinking Gatorade before exercise. The experiment will compare how each drink affects the athletic performance of 5 males, aged 18-20 who regularly exercise. Seems like a small number. It is expected that there will be no significant difference between each athlete’s VO2max and maximal exercise time when hydrated with water versus Gatorade.

Materials and Methods

How did you test to see if your individuals were healthy? A Jager Oxycon Mobile Respirometer was obtained from the Biological Sciences Department of Saddleback College in Mission Viejo, California. 5 males between the ages of 18-20, all of whom exercise regularly, were tested during a 45 minute period to measure their maximum volume of oxygen intake when hydrated by one of two substance: water or Gatorade. Testing took place in room 128 of the math and science building at Saddleback College between the dates of November 5th and November 20th, 2009. During each testing period, the Oxycon unit was connected and to a laptop running LabPro, and warmed up for 15 minutes, undergoing routine diagnostic checks. The SBx unit was connected to the PCa receiver and hooked up appropriately to carry out gas and volume calibrations before any data was collected. After passing the calibration tests, the SBx unit was put into the backpack harness and connected to the DEx unit. Each individual was given 20 minutes to drink 32 ounces of either substance, then was outfitted with the Oxycon unit, wearing it strapped to their back, with the SPO2 sensor clipped to their left ear, polar belt around their chest to measure heart rate, and the mask securely attached to their face. Each participant then rode a standard 18 speed street bicycle, set on speed 10, while their heart rate, VO2, ride time, VCO2 and other data was collected on the laptop. Each test subject rode at a comfortable speed of 5 to 8 mph for 5 minutes. After 5 minutes, each individual increased their speed by 1-2 mph and continued to do this for the following 5 minutes. When reaching 10 minutes, each subject was instructed to bike at the peek of their capabilities for as long as possible in order to accurately compare their stamina and maximum respiratory rates. Each test subject repeated this process twice, once while drinking water, and once while drinking Gatorade with at least 2 hours of rest in between tests.

Data was analyzed using Microsoft Office Excel and a paired two-tailed t-test statistical analysis was used. The test was run for both VO2max and sprint time between water and Gatorade. Neither test produced significantly different results with P>0.05. All data was expressed as a mean±SEM.

Results

Need to have your results (actual numbers) in the body of the results section, not just in a table or a figure.

VO2max is a measure of the highest rate of oxygen intake possible during maximal exercise. As exercise intensity increases incrementally, oxygen intake increases as well. However, at the point of VO2max, exercise intensity can continue to increase while the rate of oxygen intake will not. VO2max was recorded for 5 males who exercise regularly. It was measured for when test subjects drank water and also when drinking Gatorade prior to exercise testing (Table 1). No significant difference (p=0.911, paired two-tailed t-test) was found between the measure of VO2max between the water and Gatorade test runs (Figure 1).

In addition, the time that each subject was able to maintain peak exercise was recorded. The sprint time, in which subjects underwent maximal exercise, was compared between the water and Gatorade test runs (Table 1). No significant difference (p=0.311, paired two-tailed t-test) was established in sprint time between test subjects when drinking water versus Gatorade before incremental exercise (Figure 2).

| |VO2max (ml/kg/min) |Sprint Time (sec) |

|Water |2588.2(270.2 |21.6(7.6 |

|Gatorade |2639.6(351.4 |31.8(5.4 |

Table 1. Table displaying the means(SEM values for VO2max (ml/kg/min) and sprint time (sec) between the water and Gatorade exercise test runs.

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Figure 1. Bar graph displaying the mean(SEM for the difference of VO2max between water and Gatorade exercise runs.

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Figure 2. Bar graph displaying the mean(SEM for the difference of sprint time between water and Gatorade exercise runs.

Discussion

In the study, no significant difference was established between the VO2max and sprint time of the athletes when drinking water before testing versus Gatorade. Although the results with Gatorade did show an overall increase in athletic performance, the results were not considered significantly different those of water (P>0.05). This demonstrates that there is no advantage of hydrating before incremental exercise with Gatorade versus hydrating with water. These results agree with the original expectation that there would be no significant difference between the two groups.

Khanna’s (2005) study showed opposite results, concluding that there is a significant difference in athletic performance and stamina when supplementing with a carbohydrate-electrolyte drink such as Gatorade, versus a drink with no supplementation such as water. The study showed that carbohydrate-electrolyte supplementation before exhausting exercise leads to superior performance. These results likely differ from the present study due to the fact that Khanna’s experiment tested athletes until exhaustion, lasting up to 100 minutes. The length of exercise plays a large role in choosing a hydration method from a short sprint to a lengthy marathon and likely contributes to the results in the present study. If the time of exercise was increased in the study at hand, athletes would lose a greater volume of sweat enhancing the need for hydration. In addition, greater sweat loss leads to loss of sodium, potassium and other necessary electrolytes which create the osmotic gradients which help control hydration and muscle contraction (Smith 1992). Gatorade replaces these lost electrolytes and provides the body with energy in the form of carbohydrates. With a longer biking time and larger test group, a significant difference is more likely to be obtained which would demonstrate that Gatorade is a more effective hydrator than water. This could possibly lead to a higher VO2max and longer sprint time for the Gatorade test run in each subject.

Acknowledgements

We would like to thank Professor Steve Teh for his time, help and advice. In addition, we thank Saddleback College Biological Sciences Department for allowing us to use their facilities and for loaning the Jaeger Oxycon Mobile unit used in the study. Finally, we appreciate the test subjects used in the experiment for the donation of their time.

Literature Cited

Bergeron, M., J. Waller, and E. Marinik. (2006). Voluntary fluid intake and core temperature responses in adolescent tennis players: sports beverage versus water. British Journal of Sports Medicine. ProQuest Health and Medical Complete, ProQuest. Web.  Accessed 13 Sep. 2009.

Khanna, G.L., I. Manna (2005). Supplementary effect of carbohydrate-electrolyte drink on sports performance, lactate removal & cardiovascular response of athletes. Indian J Medical Resource. Vol. 121. pp665-669.

Smith, J. (1992). A Look at the Components and Effectiveness of Sports Drinks.

Journal of Athletic Training, Vol 27. #2. pp173-176.

Duvillard, V., S. Braun, W. Markofski, M. Beneke, and R. Leithauser. (2004). Fluids and Hydration in Prolonged Endurance Performance. Nutrition. Vol 20, #7-8. pp651-656.

Review Form

Department of Biological Sciences

Saddleback College, Mission Viejo, CA 92692

Author (s):_Buchan and Foire____________________________________

Title:_Comparison of Water Versus Gatorade Hydration on VO2max and Maximal Exercise Time in Athletes

Summary

Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.

I believe the topic of discussion is whether Gatorade truly matters in comparison to water. After testing 5 test subjects, you concluded that there was no significant difference, so a conclusion could not be made that Gatorade provided any significant change to an athlete’s performance.

General Comments

Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our current state of knowledge.

I believe you did a good job on your paper. The only thing that stuck out of this paper was your small sample size. 5 subjects doesn’t seem like a large enough sample size to provide an accurate sample test for the population. I would recommend commenting on the weight or height of your subjects. It simply states that they are athletic individuals. However, this allows a lot of different variables to be test, such as race, height, and weight. I’m not sure how you deemed this individuals to be healthy since in the Materials and Methods, there is no test described to assess the health of the sample group.

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