Ergogenic Aids for a Race Day Boost

Ergogenic Aids for Runners

Sometimes, you just need a little extra boost on race day. Nothing replaces proper training. However, things that can aid the full expression of your fitness are helpful for that final 1% difference. Ergogenic aids are nutritional supplements or strategies that boost performance. Ergogenic aids for runners can be legal (caffeine) or banned (steroids). Of course, these listed ones are legal and safe. For recreational runners, the most effective ergogenic aids are simple: beet juice, caffeine, and carbs. One caveat: always test them in a peak workout, never on your big goal race day!

Beet Juice

You’ve likely seen beet juice supplements in running stores and sports nutrition shops. Beet juice shots and powders are the most common, since you would have to consume 500mL of regular beet juice for full effect.

Beets contain dietary inorganic nitrates, which your body converts to nitric oxide via the enterosalivary pathway. Nitric oxide causes your blood vessels to widen, which allows more oxygen-rich blood to flow to the muscles. Greater oxygen delivery improves cellular respiration, which leads to decreased ATP demands at high intensities. Other mechanisms of action may include increases in glucose uptake, improved muscle contraction, and enhanced endurance adaptations via cell signaling.

Practically, you can produce more energy at a lower rate of perceived exertion. The research generally supports its use, especially in endurance events lasting 12-40 minutes. For most runners, distances from 5K to 10K are where you will see the most significant results. You may not notice as much effect in the marathon or ultra-marathon distances.

However, if you have low blood pressure, you should not supplement with beet juice. Do be warned also that beet juice can cause beeturia (red or pink urine), which can be alarming if you do not expect it. As with any supplement, you should always test beet juice in training. For some athletes, beet supplements can cause gastrointestinal distress.

How to Use Beet Supplements:
  • Ensure the supplement you choose provides enough nitric oxide. The ideal concentration is 5-9 mmol (310-560 mg). However, as a 2019 study found, a majority of beet supplements do not contain enough nitric oxide (>5mmol). Out of 24 tested supplements, only 5 (21%) had high enough levels to function as ergogenic aids.
  • A dose is 300-1040 mg of supplemental nitric oxide (or up 10 mg/kg body weight).
  • Take the beet supplement within 90 minutes of competition, as peak levels occur at 2-3 hours after ingestion.
  • Do not use mouthwash or brush your teeth after dosing due to the inhibitory effect on enterosalivary pathways.


One highly effective ergogenic aid for runners may already be part of your routine. Whether you opt for a cup of coffee pre-race or anhydrous forms of caffeine (such as caffeinated gels), caffeine gives a huge boost to your central nervous system and your neuromuscular system. It lowers the perception of effort and increases alertness. In the muscles, caffeine actually increases the mobility of calcium ions, which leads to more forceful muscular contractions. The result? Better performance in long endurance events. Another bonus: caffeine aids in the absorption and oxidation of carbs during running.

One big caveat with caffeine: some people respond well to it, some people have no response, and some people experience adverse side effects like anxiety, increased heart rate, and headaches. It all comes down to genetics. Additionally, dosage matters. Too much caffeine can cause side effects such as GI distress or increased heart rate. So, for example, a cup of coffee with your pre-race breakfast and a caffeinated gel at mile 22 may be beneficial. A caffeinated gel for every single gel in a marathon may be a disaster.

The only way to know is to test caffeine in training. You may find you need coffee before but then are best to skip the caffeinated gels, or that any caffeine mid-race sends you running for the bathroom. Or, a well-timed caffeinated gel could be the rocket boost you need.

How to Use Caffeine Supplements:
  • The ISSN recommends 3-6 mg of caffeine per kilogram of body weight. For a 143-lb (65-kg) runner, that is 195 to 390 mg of caffeine. Some athletes may respond to lower doses at 2 mg/kg (130 mg for the sample athlete).
  • Spread this amount out, especially if ingesting mid-race. Most running gels have 50-100 mg of caffeine; only take one serving at once.
  • Caffeine takes 45-60 minutes to peak in your system. Time your caffeine ingestion approximately 45-60 minutes out from when you most need it. A common approach is ingesting caffeine before the race and/or taking a gel an hour before the hardest part of the race.
  • Higher amounts can cause gastrointestinal distress, anxiety, or palpitations. Do not make every gel a caffeinated gel!


Carbohydrates are hands-down the best of ergogenic aids for runners. If you aren’t using them properly, the above won’t be as effective. During intensities greater than 70% of your VO2max (i.e. any race intensity above the 50K), your body uses primarily carbohydrates to produce energy. If you are low on carbs, your body switches to fatty acid oxidation, and you slow down because that process is not as efficient above 60-70% of your VO2max. That slow down is the dreaded marathon wall. However, if you carb load and replace carbs during a race, you can run faster for longer and avoid bonking.

ATP synthesis uses two forms of carbs: glycogen (stored carbs in the muscles and liver) and glucose (in the blood sugar). Carb loading with ~8 grams of carb per kg of bodyweight for 2-3 days prior to your marathon provides a significant performance boost. Carb loading increases muscle glycogen stores. A one-day carb load may be effective for distances like the half marathon if you are racing over 90 minutes.

Liver glycogen depletes during an overnight fast. This is why a race day breakfast is so important! Consuming 140-330 grams of low-glycemic carbs before the race replenishes liver glycogen. Additionally, carbohydrates in your pre-race breakfast help maintain glucose levels in your blood if you fuel during the race. The optimal time frame is to eat 2-3 hours prior to the race, to avoid GI upset.

Sports nutrition products are formulated to be quickly oxidized into energy. Practice them in training to increase your tolerance and be able to consume higher amounts per hour. Be sure to practice in training to minimize risk of GI upset. Here’s more on how to fuel during long runs and options for sensitive stomachs.

Just how much do carbohydrates help? One 2014 study at the Copenhagen Marathon found that runners who strategically consumed 60 grams of carbs per hour finished an average of 11 minutes faster than equally trained peers.

How to Use Carbohydrates As Ergogenic Aids:
  • During any race longer than 60-75 minutes, use sports nutrition products such as sports drinks, gels, or chews.
  • If the race is 60 minutes to 2 hours in length, 30-40 grams of carbohydrates per hour is effective.
  • If the race is 2-3 hours in length, aim for 50-60 grams of carbohydrates per hour.
  • For races longer than 3 hours, you can do 60-90 grams of carbohydrates per hour.
  • Spread out the carbohydrates throughout the hour, such as taking a gel every 20-30 minutes.

Housh, T. J., Housh, D. J., and DeVries, H. A. (2016). Applied Exercise and Sport Physiology  With Labs (4th ed.). Holcomb Hathaway
Jeukendrup, A. & Gleeson, M. (2019). Sport Nutrition. (3 ed.). Human Kinetics.

de Castro, T. F., Manoel, F. A., Figueiredo, D. H., Figueiredo, D. H., & Machado, F. A. (2019). Effect of beetroot juice supplementation on 10-km performance in recreational runners. Applied Physiology, Nutrition, and Metabolism, 44(1), 90–94.
Gallardo, E. J., & Coggan, A. R. (2019). What’s in your beet juice? nitrate and nitrite content of beet juice products marketed to athletes. International Journal of Sport Nutrition and Exercise Metabolism, 29(4), 345–349.
Macuh, M., & Knap, B. (2021). Effects of nitrate supplementation on exercise performance in humans: A narrative review. Nutrients, 13(9), 3183.
Van De Walle, G. P., & Vukovich, M. D. (2018). The effect of nitrate supplementation on exercise tolerance and performance: a systematic review and meta-analysis. Journal of Strength and Conditioning Research, 32(6), 1796–1808.
Vitale, K., & Getzin, A. (2019). Nutrition and supplement update for the endurance athlete: review and recommendations. Nutrients, 11(6), 1289.

(Disclaimer: This information is based on recent peer-reviewed research. However, always consult a sports nutritionist, dietitian, or medical professional before using any supplements.

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8 Responses

  1. I’m looking forward to my next training cycle for a road marathon.
    I want to test the 60 grams of carbs per hour of running/racing. I have never been systematic about my nutrition, so I’m excited to see what a difference it will make.
    Thank you for these tips, Laura!

  2. I’ve never tried beet juice, but carbs and caffeine are regular parts of my routine. Luckily I handle caffeine pretty well, so I’ve been able to add in caffeinated gels to some of my long runs and races.

  3. I’ve been fueling with Tailwind on my long distance races for years! I like to carry it in my own handheld so I can sip as I go and keep a steady level of carbs in my bloodstream. I can’t drink it full strength, tho, because it makes me nauseous. I agree that it’s important to trial fueling before taking it on a race.

  4. I don’t drink coffee at all, and I alternate green tea with decaf green tea. I do like to use caffeine for a race though! Whether it’s real or a placebo effect, I know it seems to help me.

    I actually use the caffeinated chocolates. 🙂

  5. I always feel better with a little caffeine in my system before, during, and after a race. It’s just the way I’m wired.

    I never considered beet juice. I love beets, though…

  6. Coffee and caffeinated gels are always part of race day. And carbs of course

    Have not tried beet juice yet. Thanks for the advice.

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