How to Test Your Gels During Training

Energy gels work best when you test flavor, timing, fluids, and any caffeine during training before race day.

• Start simple with one gel at a time on an easy or moderate training session.
• Test the rhythm gradually, for example one gel every 30 to 45 minutes on longer sessions.
• Take water, electrolytes, and practical factors such as bottles, pockets, and aid stations into account.
• Test caffeine in a controlled way so you know your tolerance before racing.
• Build a plan over several weeks so race day feels familiar.

When you train hard and for a long time, your carbohydrate and fluid intake can benefit from being part of the plan.

Energy gels are a practical choice for long training sessions and races, but they work best when you have tested how they suit you. Flavor, consistency, timing, fluids, and caffeine can all matter when your heart rate is high and your body is working.

Why you should test during training

A classic mistake is buying a handful of gels before a half marathon, marathon, cycling race, or triathlon and only using them once your race number is pinned to your shirt. At that point, it is less ideal to try new products.

Your stomach does not necessarily react the same way at home, on an easy training session, and after many kilometers at race pace. A gel may taste fine in the kitchen, but feel different when your mouth is dry, your breathing is heavy, and the intensity is high.

When you test your gels during training, you learn:

The goal is not to find the perfect gel for everyone. The goal is to find the gel and the rhythm that suit you, your sport, and your distance.

You can start by looking at the selection of energy gels for training and racing, so you have different flavors and variants to test with.

Start simple with one gel at a time

Your first gel test can be kept simple. Choose an easy or moderate training session of around 45 to 90 minutes, where the goal is not to set a personal best, but to pay attention to how you feel.

Take one gel after around 30 to 45 minutes. Drink water with it. Continue the session and notice how your body reacts.

The most important thing is that you only change one thing at a time. If you test a new breakfast, a new sports drink, a new gel, and a higher pace on the same session, it becomes difficult to know what suits you and what may be causing challenges.

A good first test could look like this:

It does not have to be advanced. Write it in your training app or on your phone: gel, time, water, intensity, and stomach feeling. After a few sessions, you can begin to see a pattern.

If you want to try several flavors without buying full boxes from the start, an Energy Gel Sample Mix can be a practical way to find the variants you prefer.

Find timing and amount per hour

Once you have found a gel you like, the next step is to test the rhythm.

Many gels contain around 20 to 25 grams of carbohydrate per serving, and many endurance athletes typically work with around 30 to 60 grams of carbohydrate per hour on longer sessions. Some choose to gradually increase intake, but this should be tested over time. The stomach can be trained to tolerate different strategies, just as training is adjusted gradually.

A simple model is to test one gel every 30 to 45 minutes on sessions longer than 90 minutes. That way, you get a steady supply of carbohydrate without having to take in a lot at once.

Example for a 2-hour long run:

• After 35 minutes: First gel with water.
• After 70 minutes: Second gel with water.
• After 105 minutes: Optional third gel if the session is hard or close to your race setup.

If you experience stomach issues, it is not necessarily the gel that does not suit you. It can also be the amount, the timing, the pace, or too little fluid. Try adjusting one thing at a time:

• Take the gel more slowly.
• Drink more water with it.
• Reduce the amount of carbohydrate per hour.
• Start earlier in the session.
• Practice the same strategy over several weeks.

If you want to work more systematically with higher energy intake, you can read more about how to train your stomach for higher carbohydrate intake.

Water, electrolytes, and gels need to work together

Gels are concentrated sources of carbohydrate. That is why many people prefer to take them with water, especially if they take several gels during the same training session, or if the gel has a thicker consistency.

As a starting point, 200 to 250 ml of water per gel can be a place to begin. However, the need depends on the product, temperature, intensity, sweat rate, and your personal tolerance.

Also test the practical side:

• Can you open the gel at speed?
• Can you get it down when your breathing is hard?
• Do you have water ready when you take it?
• Do you run with a vest, belt, or handheld bottle?
• Are you relying on aid stations on race day?
• Does the timing fit with your bottles on the bike?

On hot days or with a high sweat rate, it may also be relevant to include salts in the plan. Here, electrolytes for long training sessions can be part of your overall fluid strategy.

It is not about taking in as much as possible. It is about finding a balance between carbohydrate, fluid, and electrolytes that suits you and your activity.

Test caffeine with respect

Caffeine gels may be relevant for some endurance athletes. However, caffeine should be tested in advance so you know your own tolerance.

Some find that caffeine fits well into their strategy, while others notice restlessness, a high heart rate, stomach irritation, or affected sleep later in the day. That is why caffeine should not be a spontaneous experiment during a race.

Start low and controlled. Test one caffeine gel during a training session where you know the route, intensity, and conditions. It could be a longer session or a tempo segment that resembles competition, but without it being a key day.

Pay particular attention to your total caffeine intake. Coffee before the start, caffeinated gels along the way, and any energy drinks can quickly add up.

If you know you are sensitive to caffeine, test extra carefully, or choose gels without caffeine.

Build a test plan over several weeks

An energy plan is rarely built on one session. Instead, use 3 to 6 weeks to gradually test products, timing, fluids, and quantity.

A simple test process could look like this:

The closer you get to race day, the more training can resemble the conditions you expect. This applies not only to pace and distance. It also applies to sports nutrition, bottles, pockets, aid stations, and routines.

If you want to combine gels with energy in your bottle, energy powder for your bottle can be tested in the same systematic way. And if you want variety on long sessions, chews as an alternative to gels can also be part of your energy plan.

Make race day feel familiar

When race day arrives, your energy strategy should not feel new. You should know which gel you take, when you take it, how much water you drink with it, and whether caffeine is part of the plan.

Use only products and amounts you have tested in training, preferably several times and under conditions that resemble racing.

That does not promise a perfect day. Nothing does. But it can give you a more well-tested foundation for your carbohydrate and fluid intake, so you can focus on your effort.

A good gel plan is about calm, rhythm, and predictability. Once you have practiced it in training, you do not need to guess on race day.

You just need to follow the plan you have tested.