Caffeine: A performance enhancer and fat burner

Today I am looking at the role of caffeine as a fat burner and performance enhancing drug, its effects, side effects and doses. Caffeine is the most widely used stimulant drug in the world, often found in coffee, tea, soft-drinks, some non perscription medications and chocolate.

 In 1 January 2004, caffeine was removed from the 2004 World Anti-Doping Agency Prohibited List

Effects of Caffeine 

• Effects include the mobilisation of fats from adipose tissue and the muscle cells
• Alterations to the central nervous system to change perceptions of effort or fatigue
• Stimulation of the release and activity of adrenaline, and effects on heart.  

Caffeine enhances endurance performance because it promotes an increase in the utilisation of fat as an exercise fuel and 'spares' the use of the limited muscle stores of glycogen. studies now show that the effect of caffeine on 'glycogen sparing' during sub-maximal exercise is short-lived and inconsistent - not all athletes respond in this way.

The metabolic effect of caffeine are more variable in untrained people. 

There is evidence that caffeine enhances endurance and provides a small but worthwhile enhancement of performance over a range of exercises including short-duration high-intensity events (1-5 min), longer high-intensity events (20-60 min) and endurance events (90 min + continuous exercise).

Traditional protocols for the use of caffeine involve the intake of caffeine one hour prior to the event, in doses equivalent to  6 mg/kg

Newer studies in available literature suggests that performance benefits can be seen with moderate amounts 3 mg per kg of body mass of caffeine 1 hour prior to exercise. These studies show that performance benefits do not increase with increases in the caffeine dose above 3 mg/kg. The use of larger doses of caffeine increases the risk of side-effects.

Side Effects

small to moderate doses of caffeine have minor effects on urine losses or the overall hydration in people who are habitual caffeine users. Because caffeine increases the production of stomach acid it may worsen ulcer symptoms or cause acid reflux. Insomnia, poor sleep, and anxiety are well described psychological side effects of caffeine. At higher levels of intake, caffeine has the potential to cause increases in heart rate, impairments or alterations of fine motor control and technique.


At intakes above 13 mg/kg of bodymass the risk of side effects are significant


 Sudden discontinuation of caffeine in a regular user may trigger caffeine withdrawal symptoms. The most common symptoms are headache and fatigue.

References

Appl Physiol Nutr Metab. 2008 Dec;33(6):1319-34.
AIS Fact Sheet

Creatine: Muscle Building Suppliment

You've most likely heard of Creatine, and most people you meet seems to have heard something different about the supplements and, often based on incomplete or inaccurate information.

What is Creatine

Creatine is a dietary component found in meat and eggs. A typical daily intake is around 1 gram and 95% of the bodies creatine pool is found in the muscles. Daily turnover of creatine is 2 grams therefore the rest must be manufactured by the body. Vegetarians often have lower muscle levels of creatine. Most creatine in muscle is bound to phosphate.

What does Creatine do

Creatine phosphate provides a limited but fast acting system to regenerate ATP and is the most important fuel source in the performance of exercise that requires an all out effort for 5 to 10 seconds

Does Taking additional Creatine help performance

Performance studies have shown evidence that creatine suppliments improve recovery between repeated bouts of high intensity exercise. An increased level of total creatine in the muscle appears to increase the rate of resynthesis of phosphocreatine during rest periods between sprints. Creatine does not seem to enhance performance of aerobic or endurance sports.

Creatine Loading

Creatine loading is associated with an imediate weight gain of 1-2 kg, this is due to fluid retention in the muscle and urine output has been shown to be reduced during creatine loading. There is no scientific proof of muscle gain directly from the creatine but it is believed increased muscle gains can be made due to improved recovery times.

How to Creatine Load

The quickest way to Creatine Load is to take large and frequent doses of creatine suppliment for a number of days. 5 gram doses four to five times per day for 5 days. Eating a moderate amount of carbohydrates (100 grams) with each dose increases Creatine uptake. Following loading creatine stores gradually drop over a period of 4-6 weeks but a dose of 2-3 grams of creatine per day will keep loaded muscles at an elevated level.

How Safe Is Creatine 

 Evidence concerning the physical consequences of creatine usage is virtually nonexistent.


 References

Greenhaff, P.L. Creatine and its application as an ergogenic aid. International Journal of Sport Nutrition (1995) 5:S100-S110

Training and nutritional strategies for sports peak performance, John Hawley and Louise Burke