The findings appearing in the journal, Applied Physiology, Nutrition, and Metabolism, found that over three experimental trials, trained cyclists consuming chocolate milk sustained exercise for 51 per cent and 43 per cent longer then carbohydrate- (CR) and fluid replacement (FR) drink respectivly.
The latest research, funded jointly by Mars UK and publication Runner’s World Magazine, could form part of growing body of research into the potential benefits of milk in post exercise hydration and recovery, compared to sports nutrition products.
However, some sports nutritionists maintain that there are a growing number of different types of sports drinks currently being sold on the market for various purposes during exercise. These include products designed to be consumed before training or competition, to formulations designed for use during or after exercise.
Researchers from the School of Psychology and Sports Sciences at Northumbria University, England, said nine-male experienced cyclists were used to test how flavoured milk impacts on the muscles during glycogen-depleting exercise.
With declining performance during prolonged moderate-intensity exercise linked to glycogen depletion, the respondents underwent three randomised counter-balanced order trials to test potential recovery impacts.
Glycogen serves as a form of storable glucose in the body that can be metabolised for energy.
Each cyclist was tested for mean age, stature, mass, maximal oxygen uptake and associated power before testing began.
The respondents then undertook a glycogen depletion cycle followed by a recovery period where they would consume one of the three beverage types within the first 120 minutes of a four-hour rest period. Respondents would then begin the endurance cycle test. Each beverage was tested under the same conditions at a week apart from each other.
In the first trial, which studied glycogen depletion during a cycle, head researcher Kevin Thomas and his team found no differences in exercise time, the situation changed during the endurance capacity cycle though.
Exercise time for the final trial during the chocolate milk test was found to be longer generally than when cyclists consumed the FR or CR sample, said the researchers.
Researchers said that the only differences in measurable variables between the tests was that water ingested during the endurance capacity cycle was at a higher level after consuming chocolate milk than the FR drink.
“Participants cycled longer after chocolate milk ingestion than after CR ingestion, despite the beverages being isocaloric,” stated the research. “This difference could be attributable to differences in carbohydrate type and (or) fat content between beverages.”
In the glycogen-depletion trial, cyclists pedalled for alternating two minute periods until they were unable to continue at a certain performance level. During the four-hour recovery period, a psychological response test took place to measure 11 mood and appetite factors.
The final test was an endurance capacity trial requiring respondents to complete a cycle to exhaustion at 70 per cent of their associated power.
The researchers said that no feedback was provided on elapsed time and the cyclists were instructed to stay seated at all times during the testing. Warnings were given when pedal cadence dropped below a certain per minute rate for more than twenty seconds and the trial was stopped.
Source: Applied Physiology, Nutrition, and Metabolism
“Improved endurance capacity following chocolate milk consumption compared with 2 commercially available sport drinks”
Published online, doi:10.1139/H08-137 Authors: Kevin Thomas, Penelope Morris, and Emma Stevenson