Is It Time to Re-Test Your Training Zones?
You’ve been ticking off your workouts, following your plan, and pushing hard on those key sessions - but something feels off. Maybe those efforts are not as hard as they should be. Maybe you took some time off and now they are too hard. This could just be a single day when you are feeling amazing or not quite up to training. But if it continues over multiple sessions - that’s your cue to re-test your training zones.
Why Re-Test?
Re-testing your zones isn’t about making training harder (or easier) - it’s about making it accurate.
Training zones are the cornerstone of effective endurance training. They guide how hard you should be working in each session to target specific physiological adaptations and ensure your workouts are tailored to your fitness level and goals. But these aren’t set in stone. As your fitness evolves, so should your training zones.
When Should You Re-Test?
The general recommendation is every 6–12 weeks, but it varies depending on your season and goals. You might also consider testing:
- After a goal race or major training block
- When transitioning between seasons or phases (e.g., from base to build)
- After illness, injury, or a training hiatus
- When you notice your perceived effort no longer matches your training data
How to Re-Test
There are two methods of testing, depending on your sport, tools, and preferences. Most people choose the first method due to time, availability and finances.
- Field Tests: a 20-minute FTP test on the bike, a 5k run time trial, or a CSS swim test can all help reset your zones.
- Lab Testing: VO2 max or lactate threshold testing offers precise insights—but comes with a cost and lab access.
What to Do After Testing
Once you've tested, it's time to apply what you’ve learned:
- Update your zones in your training platform or watch (e.g., Garmin, TrainingPeaks, TriDot)
- Modify your pacing and effort targets in workouts
- Trust that you’re continued accuracy in training zones will lead to improved fitness
Don’t Be Afraid of a Step Back
Sometimes testing reveals a dip in performance and that’s okay. Life stress, lack of recovery, or inconsistency all play a role. Use the data as a cue to dial things in. You might need more sleep, better fueling, or just a week of reduced load. Or it might just be where you are at right now.
Remember that your training zones are dynamic. Reassessing them every few months ensures you’re working in the right ranges, building the right systems, and making real progress - not just logging kms.
If it’s been a while since you tested, reading this is your sign to check in. Your next breakthrough could start with a simple re-calibration.
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Want help testing or interpreting your results?
Let’s do it together.
Whether you’re using TriDot, RunDot, or TrainingPeaks, I’ll help make sure your zones reflect the athlete you are now—not the one from three or more months ago.
Want to try an optimised training plan that includes regular testing? Join the TriDot or RunDot project and test it and yourself out for two months for free. Use one of the links below to get started and reach out if you need any help setting up.
TriDot: https://app.tridot.com/onboard/sign-up/rebeccafear?type=105&sub=63
RunDot: https://app.rundot.com/onboard/sign-up/rebeccafear?type=112&sub=93