Column 15, April 2009

Could Caffeine improve your Performance?

A ‘Sports Legal’ performance enhancer

At the beginning of 2004, caffeine was removed from the World Anti-Doping Agency Prohibited list, allowing athletes to consume caffeine, either as part of their usual diets, or in sports foods/drinks and supplements for specific performance enhancing effects.

Australian Institute of Sport seal of approval

Caffeine has been classified by the Australian Institute of Sport as an ‘approved supplement’, ie it has been shown in scientific trials to provide a performance benefit, when used according to a specific protocol in a specific situation in sport.

Types of sporting events/workouts that may benefit from caffeine

The scientific evidence shows caffeine to enhance endurance, and provide a small but worthwhile enhancement of performance over a range of exercise sessions.

These include short high intensity events (1-5 mins), prolonged high intensity events (20-60mins), endurance events (90mins+), ultra-endurance events (4 hours+) and prolonged intermittent high intensity workouts (eg team and racquet sports).

How does caffeine improve performance?

How it provides this performance enhancement is still a little unclear.

We know that caffeine ‘spares’ the use of muscle glycogen during endurance events by increasing the use of stored fat as a fuel source, however not all athletes respond in this way, and the ‘sparing’ effect can be short-lived.

Evidence now seems to point to its effect on the central nervous system, enhancing muscle fibre contraction (improving speed), and reducing our perceived level of fatigue, giving us a type of ‘runners high’.

The benefits have been shown in both well-trained athletes, and recreational exercisers.

Performance benefits do not increase with increasing doses of caffeine

Possible negative effects of caffeine

At higher levels, caffeine has the potential to increase heart rate, impair fine motor control and technique, and cause over-arousal (which can interfere with recovery and sleep patterns).

Previously it was believed that caffeinated drinks had a diuretic effect, and could cause dehydration in an athlete, however recent research shows that caffeine at moderate doses does not promote dehydration at rest or during exercise.

How do I use caffeine to enhance my performance?

Most studies involving caffeine have been done in laboratories, rather than in real-life sports events, so more practical research needs to be done before very specific recommendations can be made.

Initially, Sports Dietitians recommended consuming caffeine in doses of 6mg/kg (300-500mg for a typical athlete) 1 hour prior to exercise.

More up-to-date evidence in exercise lasting 60mins+ show beneficial effects of taking caffeine at small-moderate levels (1-3mg/kg or 70-150mg caffeine) before and/or throughout, or towards the end of exercise when an athlete is becoming fatigued.

Some studies indicate the effects of caffeine can last from a few hours to as long as 12, but within 4 days of regular use, the body develops tolerance to many of the effects of caffeine. It may therefore be beneficial to minimize caffeine in the daily diet to maximize its performance enhancing effects during races/strenuous sessions.

Caffeine content of common dietary foods/fluids

Food/Drink	Serving Size	Caffeine (mg)
Instant Coffee	250ml cup	60 (12-169) *
Brewed Coffee	250ml cup	80 (40-110) *
Commercial Coffee	single shot	107 (25-214) *
Tea	250ml cup	27 (9-51) *
Hot Chocolate	250ml cup	5-Oct
Coca Cola	375ml can	49
Pepsi	375ml can	40
Red Bull energy drink	250ml can	78
V energy drink	250ml can	76
Lift Plus energy drink	250ml can	36
Chocolate - milk	50g bar	4-Dec
Chocolate - dark	50g bar	Aug-42

* Caffeine content in tea/coffee varies depending on brand/size of mug/the way it’s made eg Starbucks extra large coffee with strong brews can contain 500-1000mg of caffeine/serve

Caffeine content of specific sports supplements and over the counter medications

Product	Serving Size	Caffeine (mg)
Drinks
Fuel Sports Water	500mls	145
Powerade, Energy Edge	450mls	108
Gels
Powerbar Gel, 1 x caffeine	40g sachet	25
Powerbar Gel Blasts, 2 x caffeine	40g sachet	50
GU Caffeinated Sports Gel	32g sachet	20
Bars
Powerbar Performance bar with Acticaf	250ml can	76
Capsules
NFS Caffeine Max	1 capsule	200
Leppin Caffeine Caps	1 capsule	100

Practical Examples of Caffeine use for Performance (based on a 70kg athlete)*

* Note, these are just suggestions until more accurate research leads to specific guidelines

** research suggests that caffeinated soft drinks can act as a replacement for sports drinks during the last part of an event with no loss in performance.

Important recommendations

ALWAYS trial caffeine in training before using during an event to determine possible unwanted effects
A good training diet, as well as consideration to fluid/carbohydrate and electrolyte needs before/during and after training is of primary importance. Trial caffeine only once these areas are mastered and adhered to.
Large intakes of caffeine (>500mg/day) are generally discouraged by health authorities

Wishing you all an abundance of ‘runners highs’

Enjoy!

Marnie Oberer