You’ve probably heard of caffeine. The stimulant that keeps people awake in the morning, stops them falling asleep during university lectures and helps them to do those all-nighters watching Netflix (which I would not recommend)! It’s typically found in coffee and energy drinks, but it’s not uncommon to find them in sport based supplements, specifically ones aimed at running, swimming and cycling in particular.

So, what is it about caffeine that makes runners like Mo Farah take a double espresso shot 20 minutes before going out and winning 10,000m at the 2012 Olympic Games?

“As I make my way out to the track I feel this massive caffeine high come on,” Farah recalls. “I’m buzzing. My hands, my legs – everything is shaking.”

How Caffeine Works

Caffeine has the ability to help release more calcium in the muscles. This helps to boost the power provided by the muscles by increasing the strength of muscular contractions thus helping you to run faster. Research has also shown that caffeine can influence the brain’s perception of pain and exhaustion. This can help delay the onset of fatigue allowing you to run faster for longer. In addition, consuming caffine raises levels of adrenaline in the blood which helps keep us alert and focused (which definitely helps after a sleepless night and work the next day)!

A study at the University of Coventry found that “caffeine can cause a fibre type specific increase in muscle power output”, with muscles comprising mostly fast twitch fibres showing a 3% increase in power output, and those of predominantly slow twitch fibres demonstrating a 6% improvement. This tells us that caffeine can not only enhance performance in endurance events but even in sprints where a 3% difference can mean a fraction of a second which can prove crucial in winning a race!

How much Caffeine and when?

The recommended dose for caffeine to have an effect is between 2-5mg/kg. For most people, 200mg of caffeine is enough to see effects. This is about 2 – 3 cups of 250ml fresh filter coffee. For espressos, this can vary as espressos have a caffeine content varying from 30-200mg per shot (30ml).

For regular coffee drinkers whose body’s are more used to the effects of caffeine, a larger dose may be required to receive a more prominent performance-enhancing effect.

Caffeine reaches peak concentrations in blood plasma about an hour after consumption, which would suggest it is best consumed an hour before your race although the effects of caffeine can become prominent within half an hour or less of consumption. You can obtain caffeine through pills, shots, bars, coffee and various other sources. Ultimately, the source of caffeine does not matter so much as the amount ingested.

Negative Effects of Caffeine

Whilst caffeine is an awesome stimulate used by many to kickstart the day and as a performance booster, it can have negative effects such as:

  • Reduced absorption of iron – according to The Nutrition Desk Reference, caffeine can inhibit iron absorption by up to 80%! Iron is vital for red blood cell production since iron is used to create haemoglobin, the protein in your blood cells that carries oxygen to your muscles.
  • Causing a rapid or irregular heartbeat due to raised levels of epinephrine (aka adrenaline) which can raise blood pressure and increase the contractibility of your heart (the force at which your heart contracts at).
  • Insomnia – caffeine has an average half-life of around 5.7 hours. This means you should try and have your coffee early on in the day to prevent sleepless nights. If you have 200mg of caffeine, it will take 5.7 hours for half that dose to leave your body and approximately another 5.7 hours for that number to half again. The effects of caffeine are estimated to last between 8 – 14 hours and one study found that taking caffeine 6 hours before bed can reduce total sleep by one hour. The bottom line? Try and take your caffeine early in on the day to avoid sleep disruption.
  • Withdrawal symptoms if you are accustomed to taking caffeine, including headaches, sleepiness, low energy levels and bad moods.

Can you have too much Caffeine?

Well, for starters, if you want to stay ‘legal’ and perform at an elite level then you have to keep caffeine concentrations below 12 ug,ml−1 in your urine. This is a very high dosage and it is very hard to go over the limit so I wouldn’t worry about this one (just an interesting fact).

As for whether too much caffeine can compromise performance, well researchers have found that those who consume over 9mg/kg of bodyweight experience a drop in performance.

If you’re not used to caffeine, it can make you feel jittery and raise your heart rate and blood pressure. The best way to find out how to use caffeine to supplement your performance is to experiment with consumption. It can be hard to know how much caffeine you’re consuming in coffee so it may be easier to find out by taking gels or shots that list the caffeine in the product.

The final note? Experiment with caffeine intake to find out what works for you. Everyone is different.

Do you use caffeine to supplement your performance? Let me know down below!