Effects of caffeine on time to exhaustion in exercise performed below and above the anaerobic threshold

Abstract

Controversy still exists concerning the potential ergogenic benefit of caffeine (CAF) for exercise performance. The purpose of this study was to compare the effects of CAF ingestion on endurance performance during exercise on a bicycle ergometer at two different intensities, i.e., approximately 10% below and 10% above the anaerobic threshold (AT). Eight untrained males, non-regular consumers of CAF, participated in this study. AT, defined as the intensity (watts) corresponding to a lactate concentration of 4 mM, was determined during an incremental exercise test from rest to exhaustion on an electrically braked cycle ergometer. On the basis of these measurements, the subjects were asked to cycle until exhaustion at two different intensities, i.e., approximately 10% below and 10% above AT. Each intensity was performed twice in a double-blind randomized order by ingesting either CAF (5 mg/kg) or a placebo (PLA) 60 min prior to the test. Venous blood was analyzed for free fatty acid, glucose, and lactate, before, during, and immediately after exercise. Rating of perceived exertion and time to exhaustion were also measured during each trial. There were no differences in free fatty acids or lactate levels between CAF and PLA during and immediately after exercise for either intensity. Immediately after exercise glucose increased in the CAF trial at both intensities. Rating of perceived exertion was significantly lower (CAF = 14.1 ± 2.5 vs PLA = 16.6 ± 2.4) and time to exhaustion was significantly higher (CAF = 46.54 ± 8.05 min vs PLA = 32.42 ± 14.81 min) during exercise below AT with CAF. However, there was no effect of CAF treatment on rating of perceived exertion (CAF = 18.0 ± 2.7 vs PLA = 17.6 ± 2.3) and time to exhaustion (CAF = 18.45 ± 7.28 min vs PLA = 19.17 ± 4.37 min) during exercise above AT. We conclude that in untrained subjects caffeine can improve endurance performance during prolonged exercise performed below AT and that the decrease of perceived exertion can be involved in this process.

Does Caffeine Added to Carbohydrate Provide Additional Ergogenic Benefit for Endurance?

“…Thirty-three peer-reviewed research articles met the inclusion criteria (Alves et al, 1995;Bell, Jacobs, & Zamecnik, 1998;Berglund & Hemmingsson, 1982;Bridge & Jones, 2006;Butts & Crowell, 1985;Cadarette, Levine, Berube, Posner, & Evans, 1983;Cha et al, 2001;Cohen et al, 1996;Collomp et al, 2002;Conway, Orr, & Stannard, 2003;Costill et al, 1978;Denadai & Denadai, 1998;French et al, 1991;Fulco et al, 1994;Graham, Hibbert, & Sathasivam, 1998;Graham & Spriet, 1991;Greer, Hudson, Ross, & Graham, 2001;Ivy et al, 1979;Jenkins, Trilk, Singhal, O'Conner, & Cureton, 2008;Lindinger, Graham, & Spriet, 1993;MacIntosh & Wright, 1995;McLellan, Bell, & Kamimori, 2004;McNaughton et al, 2008;Norager, Jensen, Madsen, & Laurberg, 2005;Pasman et al, 1995;Powers, Byrd, Tulley, & Callendar, 1983;Sasaki et al, 1987;Slivka et al, 2008;Spriet et al, 1992;Trice & Haymes, 1995;Van Soeren & Graham, 1998; Table 3). Three research articles Berglund & Hemmingsson, 1982;Butts & Crowell, 1985) reported Note.…”

High Agreement between Laboratory and Field Estimates of Critical Power in Cycling

“…1 Whilst TTE protocols have frequently been used in sports research [8,43], they are often associated with low reliability. For example, using untrained subjects Krebs and Power [25] and McLellean et al [27] reported coefficient of variation (CoV) values ranging between 5.2-56.0% and 2.8-31.0% respectively.…”

Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study

“…It also seems to improve endurance as measured by repeated submaximal isometric contraction (34) and decreases the rate of perceived exertion during exercise (6,9,37). Typically, doses of ϳ6 mg/kg caffeine (equivalent to 4 cups of coffee) were used in these studies.…”