HIIT Interval Training on the Bike: How to Train Smart and Effectively
High-intensity interval training (HIIT) is one of the most effective and time-efficient ways to improve cycling fitness. It means alternating short, very hard periods of work with periods of rest or very easy riding. It's exactly that contrast that forces powerful adaptations in your body.
Why are intervals so effective?
A long, easy ride builds your aerobic foundation, but it's intervals that raise your fitness "ceiling". They let you spend far more accumulated time in high power zones (e.g. Z5 VO2max) than would be possible in a single, continuous effort. Short breaks allow partial recovery and get you ready for the next hard hit. As a result, interval training quickly improves your VO2max, your anaerobic threshold power (FTP), and your ability to tolerate high lactate levels, among other things.
The anatomy of an interval session
Every interval session has a few key parts:
- Warm-up (15–20 min): essential for preparing your muscles and cardiovascular system. It should include a few short accelerations.
- The main set (intervals): the heart of the session, made up of repeated work and rest periods.
- Cool-down (10–15 min): gradually winding your body down with very easy riding.
The intensity of a session like this is captured well by the Weighted Average Power (WAP) metric, and its total load is quantified by the Training Load Score (TLS/TSS).
Example interval sessions
Here are a few classic interval workouts you can do on a trainer or outdoors.
| Type of session | Goal | Example (main set) |
|---|---|---|
| VO2max intervals | Raising your VO2max | 5 x 4 minutes in zone Z5 (106–120% FTP) with 4 minutes of rest (Z1) in between. |
| Threshold intervals | Raising your FTP | 2 x 20 minutes in zone Z4 (91–105% FTP) with 10 minutes of rest (Z1) in between. |
| Anaerobic intervals | Increasing lactate tolerance | 2 sets of 6 x 1 minute in zone Z6 (121–150% FTP) with 1 minute of rest. 5 minutes between sets. |
| Tabata intervals | Maximal intensity | 8 x 20 seconds in zone Z7 (a maximal sprint) with 10 seconds of rest. |
How to fit intervals into a training plan?
Intervals are very demanding, so moderation and proper recovery are key.
- Frequency: for most amateurs, 1–2 interval sessions a week is the absolute maximum.
- Time in the season: most interval work is done in the build phase, 6–12 weeks before your main goal. In the base period, focus on longer, easier rides.
- Listen to your body: if you feel run down, skip the intervals in favour of an easier ride. Recovery is part of training.
Summary
Interval training is a powerful tool that can take your cycling to a higher level. It's demanding, but it rewards you with fast, measurable progress. Approach it thoughtfully, take care of your recovery, and regularly track your progress in the WattLog app. That way you'll train not just harder, but above all smarter.
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