Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running.

Abstract

Using a motorized treadmill the study investigated the effects of the ingestion of 3 g of caffeinated coffee on: the time taken to run 1500 m; the selected speed with which athletes completed a 1-min 'finishing burst' at the end of a high-intensity run; and respiratory factors, perceived exertion and blood lactate levels during a high intensity 1500-m run. In all testing protocols decaffeinated coffee (3 g) was used as a placebo and a double-blind experimental design was used throughout. The participants in the study were middle distance athletes of club, county and national standard. The results showed that ingestion of caffeinated coffee: decreases the time taken to run 1500 m (P < 0.005); increases the speed of the 'finishing burst' (P < 0.005); and increases Vo2 during the high-intensity 1500-m run (P < 0.025). The study concluded that under these laboratory conditions, the ingestion of caffeinated coffee could enhance the performance of sustained high-intensity exercise. Keywords: Caffeine, ergogenic acid, Vo2, blood lactate Caffeine has long been considered as a substance capable of enhancing performance or physiological functions1 and as a result of its reported ergogenic effects, the International Olympic Committee (IOC) have banned the use of high levels of caffeine. However, since caffeine is commonly found in many foods that are taken as part of the 'normal' diet, when testing for the drug the banned level is set above 15 ig ml-1 urine which is reported to represent the ingestion of 500-600 mg of caffeine (five to six cups of coffee) in a 1-2 h period2. Therefore in practical terms this dosage is only likely to be exceeded through the use of tablets, injections, suppositories or the deliberate ingestion of large amounts3. medulla increasing the secretion of catecholamines; the release of calcium ions from the sarcoplasmic reticulum; and the oxidation of free fatty acids which would produce a glycogen-sparing effect during prolonged exercise.Research into the effects of caffeine has tended to concentrate upon endurance activities such as marathon running or prolonged cyclingI7, with other investigations studying its effects upon maximal strength and power8 9. However, relatively little research has looked at the effects of caffeine upon high-intensity prolonged exercise, where the relative importance of the different physiological parameters required to produce a high level of performance and the physiological causes of fatigue can differ from those of endurance and short-term high-intensity exercise.The aim of this investigation was therefore to study the effect(s) of low doses of caffeine (approximately equivalent to the amount found in two strong cups of coffee) on a number of factors during prolonged high-intensity exercise. The study utilized doses of caffeine that would realistically be ingested by a sports performer before exercise as part of their 'normal' dietary habits without contravening the doping control regulations. Materials and methods

Effects Of Dietary Nitrate, Caffeine, And Their Combination On 20 Km Cycling Time-trial Performance

“…Moreover, the effect of caffeine supplementation on time-trial performance adds to the considerable body of previous research supporting a positive effect of caffeine on endurance exercise (10,20). Although research into the effects of caffeine on time-trial performance, particularly in well-trained athletes, is less substantive; it generally, but not always (14,22) corroborates the results of the present study (8,9,32,39,42).…”

“…In contrast to the above, the effects of caffeine supplementation on endurance performance are more clearly defined (10,20); with doses of 3 -6 mg•kg -1 producing positive effects (1.2 -4.2%) in time trial events lasting 5 -60 mins (8,9,26,32,39,42). Although the effects of caffeine were originally purported to emanate from a glycogen-sparing mechanism of action, the absence of a (maltodextrin: My Protein, Manchester, UK).…”

Caffeine Ingestion Does Not Alter Performance during a 100-km Cycling Time-Trial Performance

“…Although an ergogenic effect of caffeine has been reported in runners (46), cyclists (25), and rowers (5) who completed closed performance time trials in which a specified distance was completed in a faster time after caffeine ingestion, the duration of these trials were relatively brief, lasting from 4 min (46) to 60 min (25).…”

Caffeine increases endurance and attenuates force sensation during submaximal isometric contractions

“…Typidy, category scales have been used to assess the innuence of caffeine following an exhaustive bout of physical activity (14.15, 60). We chose to use the constant sensation technique because it does not require the interpretation of category scdes (12, 13), it provides a continuous measurement of force sensation, is highly repeatable within individual triais (see Figure 1) and can be experimentally manipulated (12,52).…”