If you believe cycling videos on YouTube, Zone 2 training must be perfect to work. No power spikes. No heart-rate drift. No standing up. Miss your target by a few watts and—according to the algorithm—you’ve supposedly destroyed the entire training benefit.
As an average cyclist (not a pro, with no chance of ever winning any races), I want to push back on that idea. Not because Zone 2 isn’t valuable—it absolutely is—but because the dogma around “perfect Zone 2” is making a lot of riders anxious for no good reason. It was making me anxious, so I dived deep into the research, and what I learned was very reassuring.
This post explains why avoiding spikes became a thing, what spikes actually do, and why most of us don’t need to panic about them. Trust me, this post will make you feel a whole lot happier about the challenges of Zone 2 training.
I like my rides on Zwift to be fun, not anxiety-inducing. This post aims to take the anxiety out of Zone 2 training, whether on Zwift or on the roadTL;DR
You don’t need perfect, spike-free Zone 2 rides to get real aerobic benefits. Short power or heart-rate spikes slightly dilute the purity of the Zone 2 signal but do not ruin the workout—especially for average cyclists training moderate hours per week. Consistency, enjoyment, and low overall stress matter far more than textbook perfection, particularly on platforms like Zwift where small surges are often unavoidable.
Related: Top 10 Scenic Flat Rouvy Routes for Big Gains in Zone 2
What Zone 2 Training Is Actually For (And Why Cyclists Use It)
Zone 2 isn’t about speed. It isn’t about watts. And it definitely isn’t about suffering.
Its purpose is very specific:
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- Build and improve mitochondria
- Improve fat oxidation
- Increase aerobic efficiency
- Create endurance with low stress and low fatigue
The key idea is this:
Zone 2 gives you the biggest aerobic return for the lowest physiological cost.
That cost-to-benefit ratio is the whole point.
Related: The Best Cycling Workouts for Longevity: Why Zone 2 Might Be the Most Powerful Ride of Your Life
Why Cycling Videos on YouTube Obsessively Warn You About Zone 2 Spikes
To understand the obsession, you need to understand who the advice was originally for.
Elite endurance athletes:
- Train 10–20+ hours per week
- Stack multiple long endurance days
- Need to preserve freshness for high-intensity sessions
- Are walking a fine line between adaptation and overtraining
For them, spikes matter because:
- They recruit fast-twitch muscle fibers
- They increase lactate production
- They increase hormonal and nervous-system stress
- They raise recovery cost without adding much extra aerobic benefit
When you’re doing massive volume, those costs accumulate quickly.
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That’s where the “no spikes ever” rule comes from.
Related: Stop Spinning Your Wheels: How Cycling Training Zones Can Take You From Casual Rider to Race-Ready
What Power and Heart-Rate Spikes Actually Do (and Don’t Do)
Let’s demystify this.
A short surge above Zone 2:
- Does not cancel your aerobic adaptations
- Does not ruin the ride
- Does not suddenly turn endurance training into junk miles
What it does do is change the training signal slightly.
Here’s how:
- Briefly recruits fast‑twitch fibers
- Produces a bit more lactate
- Shifts fuel use temporarily toward glycogen
- Raises fatigue cost relative to workload
After the surge, you may still be riding “Zone 2 power,” but metabolically you’re momentarily closer to Zone 3.
That’s not harmful—it’s just less pure.
The Key Distinction Most Cyclists Miss About Zone 2 Spikes
Spikes don’t destroy the workout. They just dilute specificity.
Instead of:
“60 minutes of clean aerobic stimulus”
You get:
“45–50 minutes aerobic + a bit of mixed intensity”
That’s still excellent training.
It’s just not laboratory-perfect.
Why Zone 2 Perfection Matters Far Less for Average Cyclists
Most of us:
- Train or ride not more than 3–6 hours per week
- Have to deal with terrain, pacing, and group dynamics—whether we are cycling to work, or cycling on Zwift
- Care about health, enjoyment, and consistency
In this context:
- Occasional spikes are physiologically trivial
- The fatigue cost is small
- The aerobic benefit is still very real
Trying to eliminate every spike often causes:
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- Mental stress
- Over-monitoring
- Less enjoyment
- Worse consistency
Ironically, that’s far more damaging than the spikes themselves. For example, for me, one of the most fun things to do on Zwift is to join a RoboPacer group. That gives me the chance to cycle with a large group of other cyclists with a similar (pretty low) FTP. It gives me a chance to practice pacing and drafting in an almost zero-stress environment. If I can’t keep up, I can just teleport out!
But the problem is that even though the RoboPacer has a set pace, there are nevertheless occasional spikes. To keep up with the group and keep earning extra XP points, I have no choice but to surge my power up for a short while. Sometimes I even have to stand up to keep up. This has been worrying me, because my other aim in doing these rides is most often to do Zone 2 training. On the rare ocaccasions that I want to do threshold training, I choose a faster RoboPacer group. And then I watch a video about the need for Zone 2 purity, and I worry that I am just wasting my time, racking up “junk miles.”
Zone 2 Training on Zwift: Why Perfection Is Unrealistic
On platforms like Zwift:
- RoboPacers surge
- Draft dynamics cause elastic effects
- Terrain changes force short power increases
- Occasional sprint segments create a huge tempation to spike your power (which I usually cannot resist, trying to beat my previous effort, or trying not to finish last!)
Whether you’re riding socially or following a pacer, micro-spikes are unavoidable.
That doesn’t mean you’re “doing it wrong.” It simnply means you’re riding a bike in a dynamic environment.
A Better, Less Anxious Way to Think About Zone 2 Training
Here’s a mental model that actually helps:
Zone 2 is a metabolic state, not a speed limit.
If you can:
- Hold a full conversation
- Ride for an hour without mental strain
- Finish feeling like you could keep going
You are almost certainly doing productive aerobic work—even if the graph isn’t perfectly flat.
Spikes are like interruptions in a calm conversation:
- Slightly annoying
- Not destructive
- Quickly forgotten
When Zone 2 Precision Actually Matters
Avoid spikes more carefully if:
- You’re stacking long endurance days
- You’re training at a very high weekly volume
- You’re struggling with recovery or sleep (an issue for me lately, which has caused me to move to more ERG-based training, for a little while)
- You’re following a strict polarized plan
If that’s not you? Then relax!
Zone 2 Training Takeaway: Consistency Beats Perfection
Zone 2 training is powerful. But Zone 2 anxiety is not. You don’t need perfection. You don’t need a perfectly flat power line. You don’t need to fear brief surges.
You need:
- Consistency
- Enjoyment
- Reasonable control
- Trust in your body
If your ride was comfortable, sustainable, and repeatable, it counted.
Don’t let YouTube dogma steal the joy—or the benefits—of endurance riding. Ride On and have fun!
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