|Posted on February 14, 2016 at 3:40 PM|
Here is a short essay I wrote during my undergraduate studies at Purdue University. Given what I know now about nutrion and the other pysiological effects that occur during exercise this may still be of benefit to some athlethes and thought I'd share something sweet with you all this Valentine's Day. Side note: if you are not a highly active individual or prehaps someone that would like to loose weight I would not suggest consuming this amount of sugar. But I'll leave that for you to decide. I hope you enjoy.
"Chocolate Milk as a Post-Exercise Recovery Aid" Journal Review
Endurance exercise is influenced by the amount of stored glycogen molecules in skeletal muscles. During this forceful endurance exercise muscle glycogen stores become depleted. To accelerate glycogen resynthesis after an intense exercise it is recommended to consume carbohydrates approximately 30 minutes to 1 hour following the training session. However, it has been shown that consuming these carbohydrates along with protein will slow the rate at which one’s body uses up the glycogen stores for energy as well as improve athletic endurance. Like many other commercial post-recovery drinks, chocolate milk, has similar carbohydrate to protein ratios to aid individuals to perform at a greater intensity the next training day. However, these substances do not have the same amounts of carbohydrates and proteins that other post-workout drinks contain and thus increasing the time of exhaustion during an exercise.
The purpose of this study was to examine the truth behind using chocolate milk as a post-workout supplement and the affects it has following an initial exercise. This experiment examined what happens to an individual’s glycogen stores when drinking chocolate milk after exercising as opposed to consuming other post-recovery aids. Learning how individuals’ glycogen re-synthesis make-up works allows scientists to possibly determine how long it may take for an athlete to become exhausted.
The subjects used for this study were nine healthy male participants, all of which are physically fit, experienced cyclists from Indiana University. The majority of the young experienced athletes were 22 years of age about 179.9cm in height and 73.0kg in weight. According to the article, all subjects participated in four testing sessions once a week. The first test the subjects were tested on their max oxygen consumption and their max power output during an incremental exercise using a cycling ergometer (model 834E, Monark, Varberg, Sweden). The other three sessions were randomized exercises each based on the individuals endurance. Each testing session consisted of two training periods separated by four hours of rest. The cyclists were given orders to monitor their diet and refrain from exercising 24 hours prior to training as well as report to the lab after fasting the night before. Once in the lab the observers had the participants complete an interval training exercise to deplete the majority of their muscle glycogen stores. After this exercise each subject consumed different recovery drinks consisting of low-fat chocolate milk (The Kroger Co., Cincinnati, OH), a fluid replacement drink (Gatorade, The Gatorade Co., Chicago, IL), or a carbohydrate replacement drink (Endurox R4, Pacific Health Laboratories, Woodbridge, NJ). Proceeding the recovery stage the cyclists performed another bout of exercise at 70% of their VO2max until failure while heart rates were recorded every 15 minutes. Blood samples were taken from each of the participants fingertips before and after each exercise trial and two hours into their recovery period. Body mass and hydration status were also recorded before and after exercise bouts using a digital scale and a bioelectrode impedance analysis.
Both chocolate milk and fluid replacement drink trials were greater than the carbohydrate replacement drink in both total work performed and time to exhaustion. However, there were no significant differences in the participants’ heart rates or their rating of perceived exertion in each of the trials performed. Body mass and hydration status did not change as well between different drinks and/or among trials.
Even though chocolate milk and the carbohydrate replacement drink have similar carbohydrate contents, and even less in the fluid replacement drink, participants cycled 49%-54% longer when chocolate milk and the fluid replacement drinks were ingested compared to the carbohydrate replacement drink. This was also the case when the participants cycled at 70% of their VO2max. Some studies have shown that this is not always the case but differences in the current study as compared to other studies may be from different methodologies, such as, cycling at different percentages of one’s VO2max. It is also possible that the different types of carbohydrate composition in the drinks may contribute to a difference in workout performance. Chocolate milk and fluid replacement drinks are very similar in this aspect, though the carbohydrate replacement drink is not. The absence of sucrose in the carbohydrate replacement drink did contribute to a shorter time to exhaustion and less total work due to less glycogen resynthesis in the liver. Glycogen resynthesis and rehydration after intense exercise is very important in obtaining optimal substrate availabilities during following exercises. Because of this the data recorded after the glycogen depletion and endurance trials suggest that fatigue during the exercise bouts occurred as a result of less glycogen stores rather than any other metabolic factor.
In conclusion, this study shows that, chocolate milk may be a more effective post-workout/recovery drink than other commercial drinks like Gatorade, Powerade, or Endurox resulting from intense exercise.