Could that morning cup of coffee really make you a better runner? Caffeine is one of the most popular ergogenic (performance enhancing) aids used by athletes and it also happens to be one of the most researched. Whether you’re an endurance runner or prefer shorter distances there are numerous studies across many sports to demonstrate caffeine’s benefits. One study in the International Journal of Sports Medicine on endurance cyclists showed performance increases using a range of different doses of caffeine. Similarly supplementing with caffeine before a 5K race resulted in faster times. Caffeine has also been shown to boost output in strength and power-based athletes.
There are a wide range of reasons why caffeine may improve performance. Firstly it can increase mental alertness and concentration enabling you to train more effectively. It does this by stimulating the central nervous system allowing the muscles to contract faster and more efficiently which may result in increased strength and power output. For endurance runners however one of the most important benefits is that caffeine increases the body’s use of fat as an energy source. Studies have shown that caffeine results in an increase in free flowing fatty acids and glycerol in the blood stream. This means when your glycogen levels begin to fall your body can still perform at your optimum. The stimulation of endorphins may also reduce your perception of effort making your run feel easier. One study published in International Journal of Sport Nutrition and Exercise Metabolism showed cyclists using a caffeinated sports drink not only completed more exercise than cyclists drinking water or a sports drink but reported a lower level of effort too.
Caffeine may also be helpful post exercise. When combined with carbohydrates researchers found restored glycogen levels were 66 per cent higher after four hours post exercise than those using just a carbohydrate based drink. In addition, drinking coffee has been shown to reduce levels of inflammatory markers. So including a shot of expresso in your post workout shake may actually improve recovery.
IS MORE BETTER?
The safest dose of caffeine for professional athletes is considered to be 5mg per kg body weight. This means that urine caffeine concentrations fall below the doping limit of the International Olympic Committee. For a nine stone runner (57kg) this would be a maximum of 285mg caffeine (see box of caffeine sources). What is particularly interesting is that taking a higher dose of caffeine does not necessarily lead to any further improvement in performance. In other words the effect is not dose dependent. At high doses many people actually experience a range of side effects, which may adversely affect health and performance (see box out).
If you are looking to use caffeine for performance enhancement it is generally recommended to take around 3-5 mg per
kg body weight about 30 minutes before exercise. Be aware that tolerance of caffeine can vary which is in part due to the ability of the body to detoxify caffeine. Caffeine can last up to five to six hours so in terms of sleeping you may wish to stop caffeine consumption mid to late afternoon. Late training sessions using caffeine could potentially affect sleep and reduce optimal rest and recovery.
Studies have also suggested that in less healthy people, detoxifying caffeine from the blood stream is much slower. One study of alcoholics demonstrated that some individuals took up to 160 hours to full detoxify normal doses of caffeine. It is also known that genetic variation can result in greater adverse effects from taking caffeine and slower elimination rate from the bloodstream. For this reason start with a low dose.
While caffeine is considered a diuretic, a recent scientific review actually found it did not result in electrolyte imbalances or exacerbate dehydration during exercise but you still need to make sure you are sufficiently hydrated during a run.
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