WHO THIS IS FOR
IS THIS YOU?
The time-crunched rider who trains mostly indoors
You have 5-8 hours per week and want to make indoor sessions as productive as possible during dark mornings and poor weather.
The outdoor rider transitioning indoors for winter
You have a smart trainer or wheel-on setup and want to know how to structure indoor training properly rather than just pedalling aimlessly.
THE ROADMAN VIEW
The Roadman view
Indoor training gets a bad reputation for being boring, and it can be — if you are just pedalling along watching Netflix with no structure. But the reality is that the trainer is the single most time-efficient training tool available to a cyclist. An hour on the trainer with a structured workout delivers more training stimulus than 90 minutes on the road because there is no coasting downhill, no soft-pedalling through villages, no stopping at traffic lights. Every pedal stroke counts.
The biggest mistake riders make indoors is treating it like an outdoor ride. You cannot ride for 3 hours indoors the way you can outdoors — the heat builds up (no natural airflow), the mental load is different, and the lack of inertia changes the pedalling dynamics. Matt Bottrill has spoken about keeping indoor sessions sharp and purposeful: 60-90 minutes with a specific target — Zone 2 endurance, threshold intervals, VO2max repeats — then get off. If the session is longer than 90 minutes, you are probably not working hard enough during the intervals.
Cooling is not a comfort issue — it is a performance issue. When your core temperature rises unchecked indoors, power output drops, heart rate drifts upward, and the session quality collapses. Professor Seiler has noted that heart-rate-based Zone 2 riding indoors can be misleading because elevated core temperature pushes heart rate higher at the same power output. The fix is simple: a strong fan (industrial, not a desk fan) pointed at your upper body, an open window if possible, and enough fluid to replace what you sweat. Get the cooling right and indoor training stops feeling like a punishment.
EXPERT EVIDENCE
WHAT THE EXPERTS SAY
- Matt BottrillMultiple national time-trial champion, cycling coach
Indoor training should be short, focused, and purposeful. A well-structured 60-minute session with intervals delivers more training stimulus than a 2-hour free-ride with no targets. The trainer is not for junk miles — it is for precision work.
Hear it: 7 Hacks Pro Riders Use That You Probably Don't | Matt Bottrill - Professor Stephen SeilerExercise physiologist, polarised-training researcher
Indoor training alters the heart-rate-to-power relationship because of heat accumulation. A rider holding 180 watts indoors will see a higher heart rate than at the same power outdoors in cool conditions. This means heart-rate-based zone targets need adjustment indoors, or better yet, train by power alone on the trainer.
Hear it: Secret To Cycling Fast At A Low Heart Rate | Prof Seiler
PRACTICAL APPLICATION
DO THIS WEEK
Set separate indoor power zones
Do a fresh FTP test on your indoor trainer in the same conditions you will train in (fan on, room temperature stable). Your indoor FTP is likely 5-10% lower than outdoor. Use this indoor-specific FTP to set zones for all trainer sessions. Do not use your outdoor FTP indoors — your threshold intervals will be too hard and your Zone 2 will be too high.
Structure three types of indoor session
Rotate between three session types: Zone 2 endurance (45-75 min steady at 65-75% indoor FTP, good for aerobic base), threshold intervals (e.g. 2x20 min at 95-100% indoor FTP with 5 min recovery, good for FTP development), and VO2max repeats (e.g. 5x4 min at 106-120% indoor FTP with 4 min recovery, good for ceiling-raising). One type per session, two to three indoor sessions per week.
Prioritise cooling and hydration
Set up a high-powered fan (800+ CFM) at chest height, pointed at your torso. Open a window if possible. Pre-fill two 750 ml bottles with electrolyte drink per hour of planned riding. If you find yourself pouring sweat but not drinking, you will lose power within 30 minutes. Cooling is the difference between a productive session and a wasted one.
COMMON MISTAKES
WHAT CYCLISTS GET WRONG
MISTAKEFree-riding for hours with no structure or targets.
FIXEvery indoor session should have a purpose — a zone target, an interval set, or a specific duration at a specific power. Free-riding indoors wastes the trainer's greatest advantage: the ability to control intensity precisely.
MISTAKEUsing outdoor FTP for indoor workouts.
FIXIndoor FTP is typically 5-10% lower due to heat, biomechanics, and lack of inertia. Test indoors and set indoor-specific zones. Outdoor zones used indoors will make threshold work unsustainable and Zone 2 work too hard.
MISTAKETraining without adequate cooling.
FIXA small desk fan is not enough. Invest in a powerful floor fan (industrial grade) and point it at your chest. Without proper cooling, core temperature rises, heart rate drifts, power drops, and the session becomes cardiovascular stress rather than targeted training.
FAQ
FREQUENTLY ASKED QUESTIONS
How long should an indoor training session be?
Is indoor cycling as effective as outdoor riding?
Why is my FTP lower on the trainer?
Do I need a smart trainer or will a basic one work?
Should I do Zone 2 rides on the trainer?
How many indoor sessions per week is too many?
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