The Real caffeine Buzz

Leading sports dietitians Taryn Richardson APD and Gregory Cox APD from the Australian Institute of Sport on everyone’s favourite morning energy fix

The coffee culture in Australia is like no other. Early morning, triathletes around the country flock to the local cafe for their daily caffeine hit. It’s all about the fourth leg, right? But what benefit does caffeine have to exercise performance and recovery for triathlon?


Caffeine is a widely used, socially acceptable stimulant found naturally in the leaves, beans and fruits of a variety of plants. The most common dietary sources of caffeine include tea, coffee, cola, energy drinks, chocolate and supplemented sports foods like gels and shots.

It’s rapidly absorbed and transported to all body tissues and organs where it exhibits a complex range of actions. Effects include the mobilisation of fat from adipose tissue and the muscle cell, changes to muscle contractility, lowering the perceived rate of exertion (how hard you feel you’re working), effects on the heart muscle and stimulation of adrenaline (the fight or flight hormone). The major benefit of taking caffeine

on exercise performance appears to be achieved by central nervous system effects, which can help reduce perception of effort and fatigue, effectively allowing you to train or race harder and longer.

There’s also some evidence to suggest that carbohydrate and caffeine in combination help to replenish muscle glycogen stores faster (carbohydrate stored in the muscle as fuel) than just carbohydrate alone following exercise where glycogen stores are reduced. That recovery latte may just have gained some scientific justification, however the amount of caffeine used to accelerate post-exercise muscle glycogen refuelling is beyond what you may typically consume in your favourite post-exercise coffee.


There’s a solid body of evidence that supports caffeine use to enhance endurance exercise performance, with studies dating back to the 1970s. Caffeine has a half-life of approximately 6-7hrs, with peak blood concentrations occurring around 45-60mins. Individuals respond differently. Some feel energised, focused and ready to perform; others don’t feel or notice any perceptual changes; and some are affected negatively, suffering from nervousness, gut upset, anxiety, irritability, headaches, heart palpitations and an inability to focus. Given the varied response, it’s important to trial caffeine in training before any thought of introducing it into a race.


Previous recommendations for caffeine use during exercise were around 6mg/kg body mass (420mg for a 70kg athlete), consumed 60min prior to the start of exercise. More recent evidence suggests doses as low as 1-3mg/kg body weight (70-210mg for a 70kg athlete) are enough to enhance endurance performance – so more is not simply better.

Caffeine taken before exercise – spread throughout the event, or taken late in the race when fatigue starts to set (i.e. in an IM) – appears to assist exercise performance. Furthermore, caffeine withdrawal for a few days doesn’t appear to enhance the beneficial effects of caffeine use during exercise for habitual users.

If you currently use caffeine or are intending to use it, start with a low dose (1mg/kg) in training and build up to develop your own protocol that enhances performance using the lowest effective dose for you. Also, play around with taking it 30-60mins before training, part way through an extended session and/ or towards the end of a long session to determine the best protocol for your individual needs.


■ For nervous ODT racers, consider using it just before race start, following your warm-up to avoid the heightened sense of arousal commonly caused by caffeine intake during the pre-race period.

■ Regular low doses of caffeine throughout a 70.3 or IM can be just as effective as a large single one- off dose before the event.

■ For an IM, a strategy that may work is to introduce a caffeine dose four hours into the ride to spark you up in anticipation for the start of the run.


Caffeine consumed as instant coffee or as a supplement went head to head in a cycling time-trial study published in 2013. They found no difference in performance between the two means of ingestion. The use of coffee may be the preferred option because of taste and smell – and it seems less controversial than taking a supplement – however be mindful of the volume of coffee you need to consume to reach the same caffeine content. There’s also no guarantee of the exact caffeine content of coffee, which you’ll see by the ranges shown in Table 1.


The effects of high caffeine doses can be negative, such as increased heart rate, anxiety, over-arousal and impaired fine motor control. Also be aware of the side effects of withdrawal, e.g. headaches and lethargy. The other major factor is caffeine can interfere with sleep patterns, affecting your body’s ultimate form of recovery. And lastly, it’s not a substitute for quality training and race experience – so it shouldn’t be considered for younger triathletes.


Caffeine has a proven performance-enhancing benefit for endurance sports like triathlon. If you’re considering using it as a supplement, try it in training first. Start at a low dose and manipulate the dose and timing to develop your own personalised protocol. An Accredited Sports Dietitian can help you individualise your plan and incorporate other nutritional strategies to maximise your performance for racing.