An ergogenic aid is a food, supplement or technique that may improve athletic performance. We all respond differently, so if you are tempted to use an ergogenic aid, trial doses, timing, monitor adverse effects and what is the best source of that aid for you.
Whatever you do, it helps to remember the two golden rules: never try something new on race day and no ergogenic aid will compensate for an inadequate diet.
1. Caffeine
Ergogenic Effect
Caffeine decreases the perception of effort and fatigue. Athletes simply feel less tired and can perform at higher intensities for longer.
How Much and When?

Historically 6mg caffeine per kg body weight has been used in trials but recent research using 1-3mg/kg has shown equal benefits. The effect of caffeine is highly individual and it is worth experimenting with different doses and timings to find your own prescription. Once the performance improving dose has been identified there is no benefit in taking more.
Caffeine absorption begins in the mouth and takes 45-90 mins to reach maximum levels in the circulation. ½ the caffeine dose is still in the blood stream 6 hours after consumption.
In the past it was felt that athletes benefited more from caffeine supplementation if they decreased their habitual intake, however, more recent research has dispelled that as a myth with people taking a low, moderate and high intake of caffeine benefiting equally from the performance gains from supplementation.
In what form?
Typical amounts of caffeine
Drink/supplement | Average amount of caffeine (mg) | |
Instant coffee | 250ml | 60 |
Brewed coffee | 250ml | 80 |
Black tea | 250ml | 25 |
Hot chocolate | 250ml | 5-10 |
Cola | 330ml | 45 |
Gel | 33-35g sachet | 10-50 |

Who Could Benefit?
- Team and racquet sports
- Running at high intensities for 20-60 minutes
- People taking part in longer duration events and team sports may benefit from taking caffeine at intervals during the event
Contraindications
- Increased heart rate, palpitations
- Shakiness
- Sleeplessness. Taking caffeine late in the day may interrupt sleep
- Anxiety
- Gastro intestinal upset.
2. Beetroot Juice

Ergogenic Effect
Beetroot juice and green leafy vegetables are high in nitrate.
Nitrates are converted firstly to nitrite by bacteria in the mouth then to nitric oxide in the stomach. Nitric oxide causes blood vessels to dilate and consequently a greater volume of blood and oxygen are delivered to muscles. Essentially, the exercise is more efficient and feels easier so greater effort can be made thus improving performance
How Much and When?
Researchers have used varying amounts of beetroot in their studies and there is no consensus on the optimal dose. Bearing this in mind and individual variation in response, 300-600mg nitrate, the amount contained in 0ne or two concentrated 70ml beetroot shots or 500-1000ml juice are the doses most commonly used in research.
The benefits of beetroot juice are likely to be better if it is taken for several days prior to a race and then a few hours before the event.
It takes up to two hours for nitrate to be converted into nitric oxide and to start reaping its performance boosting benefit.
A nitrate rich diet has numerous health benefits including lowering blood pressure, so tuck into vegetables like spinach, rocket, celery, lettuce and beetroot. 250g of nitrate rich vegetable contains about 300mg nitrate (the amount in a 70ml beetroot juice shot) however, vegetable nitrate level does vary depending on farming techniques, fertilisers and soil composition

Emerging evidence suggests that nitrate may improve cognitive function. This would be helpful with coordination, reaction time and concentration in longer duration events when cognition can decline.
Who Could Benefit?
- High intensity exercise requiring the use of fast twitch muscles
- Runs up to 10km
- Athletes at high altitude where oxygen availability is lower
- Possibly for endurance runners
Contraidications
- Nitrate is safe to consume and is not carcinogenic, but direct consumption of nitrite could be toxic and should be avoided
- Until further research identifies safe and optimal doses of nitrate it would be unwise to take more than two beetroot shots daily
- Beetroot juice contains fermentable carbohydrate which can be problamatic for people prone to IBS
- You may start passing pink urine and stools
Note: Anti-bacterial mouthwash and chewing gum alter mouth bacteria which will reduce the conversion of nitrate into nitrite
3. Tart Cherry Juice
Ergogenic Effect

Not all cherries are equal. The Montmorency cherry is especially high in polyphenols, melatonin and anthocyanins. These compounds may reduce inflammation and muscle soreness, aid sleep and help recovery when the aim is to recover for another bout of exercise and the focus is not on exercise induced adaptations.
The mechanisms continue to be researched as are the sports for which it is especially helpful and whether timing, with or without food are important.
How Much and When?
Given the lack of clarity in the research, the following are guidelines taken from the protocols used in the research to date.
It is recommended that you drink 30ml of tart cherry concentrate diluted with 100-200 ml water twice a day, once in the morning and again in the evening. You can start the regime a week before your major event and maintain intake for up to five days after for maximum benefit.
Who Could Benefit?
- Anyone taking part in multi day events or more than one bout of exercise in a day
Contraidications
- Fermentable carbohydrate in cherries may exacerbate IBS symptoms
In Summary
Caffeine | Beetroot Juice | Tart Cherry Juice | |
Dose | 1-3mg/kg body weight | 500-1000ml juice or 1-2 shots of 70ml concentrated beetroot juice | 30ml concentrate diluted with 100-200ml water or 200-250ml juice |
When | 45-90 mins pre exercise | Several days prior to event 2 hours before event | Twice a day 1-7 days before and 1-5 days after an event |
Performance benefit | Reduces perception of effort and fatigue | Improves oxygen efficiency so greater effort can be given Improved cognition and reaction time during longer events | Recovery when performance at next run is important |
Which run distances/times | When running for longer than 20 minutes, or shorter distances run at high intensity. | Runs of 5-30 minutes at high intensity. Endurance runs. | During competition or ultra-endurance runs taking more than one day More than one run per day |
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