This column will allow you to do that, by summarizing specific studies that can help (or hinder) your goals in the gym.
Although a majority of studies have tested caffeine's effects in endurance performance (1,2,3), some research protocols have also measured caffeine's effects on short-term high-intensity exercise (4,5). The purpose of this current study was to determine if supplementation with creatine monohydrate would negate the known ergogenic effects of caffeine, as one previous study had demonstrated (6).
Fourteen male subjects were tested on four different occasions. A preliminary test was first utilized to obtain a VO2 max (maximal oxygen uptake). Next, during the pretreatment period, all subjects were provided with creatine and underwent a loading regimen for 6-days (0.3 g/kg bodyweight taken at 4 regular intervals throughout the day) and completed a test at a running speed of 125% of their previously measured VO2 max.
Next, 12-24 hours after the completion of the creatine loading phase, subjects were provided with caffeine (5mg/kg) or placebo and completed the same abovementioned VO2 max test. The moral of the story is that this study demonstrated that acute ingestion of caffeine still has ergogenic benefits for short-term exercise regardless of previous creatine ingestion.
Medicine & Science in Sports & Exercise, Volume 34, Number 11, 2002
Mike Doherty, Paul M. Smith, R. C. Richard Davidson, and Michael G. Hughes
The primary aim of this study was to compare the effects of aerobic vs. anaerobic training on energy expenditure (EE) and substrate oxidation. It has been discussed ad nauseam whether cardiovascular exercise or weight lifting is better for weight loss; however, much of the discussions have been based on anecdotal evidence rather than actual research.
This study tested 10 non-obese male subjects on four separate occasions using whole-room, indirect calorimetry. The first measurement was utilized to obtain a baseline EE. Next, in random order, 3 more EE measurements were completed over a 4-week period: 1) an aerobic-exercise test (stationary bike at 70% VO2 max); 2) resistance-exercise (4 sets of 10 different exercises at 70% of exercise-specific 1 RM); 3) a non-exercise control day.
During the bike session, subjects exercised for 49 ± 2 minutes and expended 546 ± 16 kcal. The 60-minute circuit training lifting regimen resulted in a 448 ± 21 kcal EE. Both exercise regimens had similar effects on substrate oxidation (there were no differences in fat oxidation over 24 hours, but there was an increase in the amount of carbohydrates oxidized).
Looking only at the results from this study, we can infer that if the primary goal with an exercise program is weight loss (with no regard to the composition of that loss) there is a greater EE during aerobic exercise than a circuit type anaerobic exercise program.
What I can infer from this and other similar studies is what bodybuilding.com reader in their right mind wants to lose their hard-earned lean body mass by only doing aerobics? Granted, most of the research coming from this group of scientists is with overweight and obese subjects; therefore, and they did mention this, these results cannot be extrapolated to bodybuilding or powerlifting type routines, but is still useful if you have clients you train.
Medicine & Science in Sports & Exercise, Volume 34, Number 11, 2002
Edward L. Melanson, Teresa A. Sharp, Helen M. Seagle, William T. Donahoo, Gary K. Grunwald, John C. Peters, Jere T. Hamilton and James O. Hill
Researchers are finally starting to branch out with their hypotheses about creatine's functions, instead of just trying to determine if creatine supplementation increases lean body mass-we've known that for years now. To my knowledge, this was the only study of its kind to measure how creatine supplementation effects substrate utilization at rest.
The authors of this study hypothesized that creatine supplementation would result in a downward shift from fat, the typical resting substrate utilization, to an increase in carbohydrate utilization. Subjects participated in a 12-week resistance training program and in a double-blind, crossover design, were given creatine (20g/4 days, followed by 2g/day for 17 days) or placebo in two separate trials.
Each trial was separated by a 4-week washout period [research has shown it takes about 30 days for creatine stores to return back to normal after supplementation (7)] and were then again given supplemental creatine or placebo.
Although the primary outcome of the study was to determine the effects of creatine on substrate utilization, what creatine study would be complete without measuring gains in strength? So, just to cover the study in its entirety, here is my brief summary. Strength (measured by 1-RM bench press) increased in the creatine group vs. placebo group and there were no significant differences in body composition.
As for substrate utilization, carbohydrate oxidation was increased during creatine supplementation (as there was a trend for an increase in respiratory exhange ratio (RER); a higher RER means more carbs are being "burned" and lower RER demonstrates greater fat utilization).
The exact mechanism is unclear, so more research is definitely warranted. The authors concluded that these results demonstrate individuals who supplement with creatine may decrease their ability to lose fat due to the RER increase.
Journal of Applied Physiology, 93, 2002
M. Erik Huso, Jeffrey S. Hampl, Carol S. Johnston
So what have we learned today in the first installment of this column?
- Caffeine intake may enhance performance, regardless of simultaneous creatine ingestion.
- Aerobic exercise will utilize more energy in a shorter amount of time than a circuit-training anaerobic regimen.
- Creatine supplementation may inhibit fat loss.
- Cohen, BS, Nelson, AG, Prevost, MC, et al. Effects of caffeine ingestion on endurance racing in the heat and humidity. Eur J Appl Physiol Occup Physiol 1996;73:358-363.
- Pasman, WJ, van Baak, MA, Jeukendrup, AE, de Haan, A. The effects of different doages of caffeine on endurance performance time. Int J Sports Med 1995;16;225-230.
- Graham, TE, Hibbert, E, Sathasivam, P. Metabolic and exercise endurance effects of coffee and caffeine ingestion. J Appl Physiol 1998;85:883-889.
- Anselme, F, Collomp, K, Mercier, B, Ahmadi, S, and Prefaut, C. Caffeine increases maximal anaerobic power and blood lactate concentration. Eur J Appl Physiol 1992;65:188-191.
- Bell, DG, Jacobs, I, and Ellerington, K. Effect of caffeine and ephedrine ingestion on anaerobic performance. Med Sci Sports Exerc 2001;33:1399-1403.
- Vandenberghe, K, Gillis, N, Van Leemputte, P, Van Hecke, F, Vanstapel, F, and Hespel, P. Caffeine counteracts the ergogenic action of muscle creatin loading. J Appl Physiol 1996; 80:452-457.
- Hultman E, Soderlund K, Timmons JA, Cederblad G, and Greenhaff PL. Muscle creatine loading in men. J Appl Physiol 1996; 81(1):232-7.