Ergogenic Aids for Runners

Ergogenic Aids for a Race Day Boost

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!

Ergogenic Aids for Runners

Beet Juice

Yes, beet juice!. Or, more realistically, beet juice shots and powders, since you would have to consume 500mL of regular beet juice for full effect. Beets contain inorganic nitrates, which your body converts to nitric oxide. Nitric oxide causes your blood vessels to widen, which allows more oxygen-rich blood to flow to the muscles. The more oxygen rich blood, the more energy you can produce at a lower effort. The research generally supports its use, particularly in distances such as the 5K and 10K where you use some anaerobic energy systems.

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.


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.


Carbohydrates are hands-down the best of the 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.

During any race longer than 60-75 minutes, sports nutrition products (gels, chews, sports drink) will boost performance. Sports nutrition products are formulated to be quickly oxidized into energy. If you are running a marathon, intra-race carbohydrates are even more important, with 60 grams of carbs per hour of racing being optimal. 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. 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.


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.

(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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6 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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