Caffeine is the most commonly consumed legal ergogenic substance in recreational and competitive athletes around the world. (1) But is taking it really useful for athletes, or is supplementation with caffeine even damaging doping?
Caffeine is under special observation
From 1984 to 2004, caffeine was on the doping list of WADA (World Anti-Doping Agency). This is no longer the case since 2004, as it is impossible to differentiate caffeine levels in urine by legal intake of caffeine-containing foods or illegal deliberate intake of caffeine to increase performance (doping). (2) Nonetheless, caffeine is used for any normal drug control tested. The wax is under special observation. If there is frequent evidence of improper caffeine use, this substance could quickly come back on the list.
Coffee is the basis of a very great culture of enjoyment all over the world. Just as with many other foods, the effects on the body and thus on the health depend on the dose. In its pure form, caffeine appears as a white, odorless, crystalline powder with a bitter taste.
The effect of caffeine is very broad. On the subject of influencing physical performance, one can cite the following effects:
- The mobilization of intracellular calcium may result in poorer sodium permeability into the cell, and thereby in inferior cell membrane excitability.
- Metabolic and hormonal adaptation.
- Promotion of lipid metabolism - but only so small that it can not be used to promote the weight loss process.
- Central nervous system stimulation: Caffeine acts on the sensory parts of the cerebral cortex, which may be conducive to increased concentration and memory capacity in the learning process. An effect could be re-observed after caffeine intake was suspended for at least 24 hours.
- Enlargement of the coronary vessels, which supply the heart muscle with blood. The heart beats stronger and faster, the blood pressure rises.
- Caffeine promotes wakefulness and attention, thus increasing the ability to concentrate.
- Allergy-reducing, as caffeine reduces the secretion of histamine and expands the bronchi.
- Diuretic effect
4 cups a day are normal
A normal caffeine consumption per day is about 4 cups of coffee. Coffee has the highest caffeine content (50-100 mg) compared to other substances such as energy drinks (30-40 mg), cola (10-20 mg), tea (30-50 mg), milk chocolate (15-20 mg) or cocoa (10 mg).
When caffeine was still on the doping list, the limit was up to 12 μg / ml urine. That's a tremendous amount and it takes a lot of dedication to get that value. Among other things, some cyclists who tested positive for doping have found a caffeine value of up to 40 espressos in their blood.
Studies on caffeine
At the Goethe University in Frankfurt am Main they wanted to test the exact effect and dose of caffeine on aerobic and anaerobic performance. For this purpose, a meta-analysis was carried out. For the operationalization of athletic performance different methods and dosages have been compiled.
Methods for recording aerobic performance:
- Constant Work Test : Define a defined distance in the shortest possible time. This test corresponds to a classic competition situation in the endurance sports.
- Constant-Power-Test: Maintain specified constant power as far as possible until load interruption due to fatigue.
Methods for recording anaerobic performance:
- Anaerobic test: To record a short-term maximum load based on the highest possible average to maximum wattage during a 30-second loading period.
- Sprinttest: The time required for a defined distance (usually 20-30 m).
The predefined dose of caffeine was administered to the subjects of the group for aerobic performance 30-60 minutes before the test and also during the test. Subjects for anaerobic performance received the predefined caffeine dose once 45-60 minutes before the start of the test.
Effects on aerobic efficiency
In 12 out of 17 meta-analysis studies, caffeine intake of 2.3-9.0 mg / kg body weight, especially in Constant-Work-Test, showed significant results. This indicates a high efficacy of acute caffeine intake by improving the defined distance.
Effects on anaerobic performance
One out of five studies showed significant changes in anaerobic potency through caffeine intake. Thus, the results of the studies show rather mixed results. Conversely, it can be stated that there is strong evidence that caffeine intake does not effectively affect the sprint time.
Excessive intake of caffeine
Regular and over-consumption of caffeine may alter the feedback processes in the brain and nerve tissue and lead to a caffeine effect. (3) The habituation effect may possibly be reduced by giving up caffeine at least 7 days before training or competition. ( 4) However, it could not be clearly shown that improved cognitive performance occurs when caffeine intake is re-introduced. In addition, caffeine withdrawal can lead to physical symptoms such as headache, drowsiness, fatigue and mood swings. Overdose may cause rapid heartbeat, rapid heart rate, increased blood pressure and gastrointestinal discomfort, insomnia and depressive states.
In addition, further studies have demonstrated diuresen (an up to 30% higher urine volume compared to the placebo group) and a significant increase in sodium excretion. Thus, the glass of water is useful for espresso.
By the way, caffeine was on the doping list in equestrian sports.
Basically nothing speaks against a dietary supplement with caffeine in sports, as long as you do not take it regularly. A necessary increase in the dose for preserving the effects should give you food for thought. Because this is the first sign of a caffeine addiction.
Author: Marina Lewun
1. Burke (2008). Caffeine and sports performance. Applied Physiology, Nutrition, and Metabolism, 33 (6), pp. 1319-1334.
2. Tran, Hübscher, Thiel, Banzer (2012). Efficacy of acute caffeine intake on aerobic and anaerobic performance. Competitive sports 4 (42), p. 45-49
3. Graham (2001). Caffeine and exercise: metabolism, endurance and performance. Sports Medicine, 31 (11), pp. 785-807
4. van Soeren & Graham (1998). Effect of caffeine on metabolism, exercise endurance, and catecholamine res -ponses after withdrawal. Journal of Applied Physiology, 85 (4), pp. 1493-1501.