American College Of Sports Medicine Review, Part I.

Each year at ACSM's Annual Meeting, researchers, scientists, dietitians, physicians, etc. gather to discuss the latest research. In this article I will present information about energy drinks, and carbohydrate and antioxidant supplementation.
Part 1 | Part 2

I recently returned from Nashville, Tennessee-home of country music and such music legends as Dolly Parton and Elvis Presley. I wasn't still searching for Elvis; I'm pretty sure he is no longer alive. Instead, I was at the 52nd Annual Meeting of the American College of Sports Medicine (ACSM).

ACSM is the largest sports medicine organization in the world. Each year at ACSM's Annual Meeting, researchers, scientists, dietitians, physicians, and other health practitioners gather to discuss the latest happenings related to nutrition, exercise physiology, and rehabilitation, to name but a few. I've dug through the 1000's of research presentations and abstracts to bring the latest research to the Lean Body Coach readers.

Before I start, some quick definitions might be useful for those who are less familiar with the research process.

  • Double-blind study: The researchers and subjects are both "blinded" as to which product is which (the experimental product vs. placebo).

  • Crossover-trial: groups of subjects are tested using both products (e.g., creatine and placebo) to ensure there is nothing unique about the subjects which would result in an effect.Trials that use this method typically allow some time between experimental trials to ensure there is no "residue" left from the previous product (e.g., creatine takes about 30 days to fully return to normal, physiological levels, so a crossover trial with a creatine study would need to have at least 30 days between trials).

The Effect Of An Energy Drink On Cycling Performance In Male Athletes

Energy drinks are all the rage. Red Bull may have started the trend, but dozens of others have followed and are popular among many athletes.

This study was one of a handful to actually consider the effects one of these popular drinks has on performance.

The purpose of this particular study was to measure the effects of an energy drink on cycling performance. The study was a double-blind, placebo controlled, crossover trial in which subjects participated in three 50 km (about 31 miles each) cycling trials.

The variables in this trial were 1 minute time trials, 4-km time trials, ratings of perceived exertion (RPE), and gastrointestinal (GI) symptoms.

    Results: There was no difference in GI symptoms between the two products, demonstrating that they were at least tolerable. There were also no performance benefits to taking the supplemental energy drink when compared to the placebo.

    Bottom line: Energy drinks did not enhance performance in this trial. Real food provides the best source of energy.

Carbohydrate Supplementation Enhances Mood & Decreases Perceived Exertion During Endurance Exercise

Despite how carbohydrates have been demonized in the media and popular literature, they are clearly the primary source of fuel for exercise and energy metabolism. Carbohydrates are stored as glycogen in muscles and liver; once this glycogen is depleted (through intense exercise), performance and mood both decrease. Therefore, the purpose of this study was to determine the effect of carbohydrate on exercise mood enhancement and assess these mood changes during the exercise bouts prescribed (60 to 105 minutes) in addition to measuring the ratings of perceived exertion (RPE).

Fourteen subjects participated in this double-blind, crossover study. At the start of the time trial and every 15 minutes throughout the study, subjects ingested either a 12% glucose solution (0.7g/kg bodyweight) or a placebo. All subjects were also allowed to drink unlimited amounts of water throughout the trial. During these same 15 minute intervals, mood was assessed using a validated Feelings Profile and RPE was measured every 5 minutes.

    Results: There was a significant improvement in mood state according to the Feelings Profile in the carbohydrate group vs. placebo. There was also an increase in RPE (meaning subjects felt as if they were working harder) in the placebo group. This change was significant from the carbohydrate group towards the end of the trial.

    Bottom line: Carbohydrates are useful during extended exercise sessions to enhance mood and performance. This may help performance and strength during extended workouts in the weight room. It's actually most important to have that carbohydrate immediately after a workout to support recovery (and it should be combined with some protein as a recovery beverage).

Effects Of Antioxidant Supplementation & Exercise Training On Erythrocyte Antioxidant Enzymes

Erythrocytes are red blood cells, which are responsible for the exchange of oxygen and carbon dioxide between the lungs and the body tissues. We all know exercise is crucial for optimal health, but it also increases oxidative stress resulting in erythrocyte damage and turnover.

Therefore, it is thought that antioxidants (through food and/or supplements) may blunt the otherwise negative effect of exercise. Again, this is not to say exercise is bad by any means; it just reminds us that we need to ensure a high intake of nutrients through our diet.

This study examined the effects of two known antioxidants, vitamin E and alpha lipoic acid (doses not listed in abstract), and/or endurance training on the antioxidant defenses of erythrocytes in male rats. Rats were assigned to one of four:

  1. sedentary
  2. sedentary and antioxidant supplement
  3. endurance trained
  4. endurance trained and antioxidant supplement

Several markers of known enzymes that are affected by oxidative damage were then measured.

    Results: Antioxidant supplementation alone had no significant effect on the markers in sedentary animals. Endurance training alone also had no effect. When combined, however, antioxidant supplementation and endurance exercise saw significant changes in a number of enzymes that were measured in this trial.

    Bottom line: This is one of many trials that has measured the effects of antioxidants and exercise on oxidative damage. More research is clearly necessary to determine the true effects because many studies using other known antioxidants have shown no benefit at all.

    For now, what we do know is that a diet high in fruits and vegetables, which provide many more antioxidants, nutrients, and other phytochemicals than any pill could ever provide are the best line of defense. Stay tuned for more research in this area, though. Part II of this report which looks at some other similar research.

That wraps up the first part of the first part of my ACSM overview. Stay tuned and next month I'll cover a number of other presentations and research studies presented.

Be Sure To Also Check Out:
Mohr Research Main Page

Part 1 | Part 2