posted 20th October 2026
By Jon Shaw, Ironman Certified Coach, ESCI Certified Coach Your Coach page
It’s Tuesday morning. You’ve got an easy Zone 2 run on the plan…
The legs feel pretty good. You’re feeling fresh, the weather is decent and everything is going nicely. Then you reach a hill.
Your watch says you’re running too slowly.
Your training plan says you’re doing exactly what you should.
Which one are you going to listen to?
That little voice in your head starts…“Come on, you can run this a bit quicker.” So, you push a little harder. You crest the hill, your pace picks up, and you feel pleased with yourself. You felt strong, after all. Another decent-looking run on Strava.
Except there’s a problem. That was supposed to be an easy aerobic session. Twenty-four hours later, you turn up for your key threshold workout and the legs don't feel anything like they did yesterday.
The target pace feels harder than it should. Heart rate is higher than expected. And suddenly the quality session you really needed isn't quite there.
This is where a lot of athletes get caught out. They don't need more fitness. They need more discipline around the fitness they've already got.
You’ve taken a session that was supposed to help you recover and build your aerobic base and turned it into something harder simply because you didn't want the run to look slow.
And over time, that can start to cost you.
Zone 3 isn’t the enemy
There’s nothing wrong with running in Zone 3. There are plenty of reasons to include steady and tempo running in an endurance programme.
The problem comes when you intended to run easily but gradually turn the session into something moderately hard because the pace looks nicer on your watch. That's when you can end up with a week full of sessions that are all just a little bit harder than they should be.
And that's where the problem starts.
So why does this matter?
Unplanned moderate running can be a problem when it replaces genuinely easy running and compromises the quality sessions that matter. You’re just adding another chunk of fatigue. And that matters because training isn't simply about how hard you can work on any given day.
It’s about how well you can absorb the training and then turn up for the sessions that matter.
1. You’re adding stress that you probably don’t need
A true easy run is relatively low stress.
That’s part of its value.
You can get some useful aerobic adaptations while keeping the overall demand on the body relatively manageable. Start pushing that pace into a moderate effort and the stress goes up. For someone already balancing training with work, family, poor sleep and all the other things life throws at us, that extra stress can become significant.
The issue isn't one slightly-too-fast run.
It's what happens when every easy run is a little bit too hard.
2. Harder doesn't automatically mean better
There's a temptation in endurance sport to think that if a little more intensity is good, then a bit more must be even better.
It doesn't work like that.
The purpose of your Zone 2 work is to develop your aerobic system while keeping the overall cost of the session relatively low. The body is still adapting. You're still improving your aerobic capacity and efficiency. But you're not burning through the same amount of energy or creating the same level of fatigue as you would in a harder session.
So, when you turn that run into a steady, moderate effort just to protect your average pace, you may be paying more for the session without getting a proportionally better return.
3. This is where the “junk miles” problem can creep in
This is the bit I see quite often.
Easy runs become moderate.
Moderate runs become hard.
Then when a genuinely important quality session comes around, the athlete isn't properly recovered. They aren't resting deeply enough to absorb the training, but they aren't fresh enough to really nail the harder sessions either.
Everything becomes a bit… meh.
You’re working hard but you're not necessarily moving forward as quickly as you could. This is where I think we need to take Strava out of the equation.
The Infinite Endurance Zone 2 reality check
The next time you're out for an easy run, try these three simple checks.
The Talk Test
Can you hold a proper conversation?
Not: “Yeah… fine…” while desperately trying to get enough oxygen in.
I'm talking full sentences without needing to stop and breathe halfway through them. Try breathing through your nose for a couple of minutes during an easy section of the run. If you're really struggling and feel like you need to open your mouth to get more air, that's a pretty good sign that your effort has crept up. It isn't a laboratory test, but it's a good reality check.
These are useful clues, not precise measurements.
Nasal breathing varies between individuals, so don't use it as the only way to judge your intensity. Your heart-rate zones need to be set appropriately for your current fitness, and your breathing, perceived effort and heart-rate response should all help build the picture.
Look at Your Heart Rate
On a relatively flat, steady run, look at what happens to your heart rate. If you're holding roughly the same pace but your HR keeps climbing significantly as the run goes on, that can tell you something useful.
It might be dehydration.
It might be heat.
It might simply be that you're carrying more fatigue than you realised.
Or it might be that the pace was too ambitious from the start.
The important thing is not to obsess over one number. Look at the whole picture. How does the run feel? What is your breathing like? What's happening to your HR? What have you got coming up in the rest of the week?
Don't Race the Hills
This is probably the easiest one to get wrong.
You're halfway through your easy run and suddenly the road points upwards and your watch says 4:50/km.
Your running ego says: “Not a chance.”
But if the purpose of today's session is easy aerobic work, the hill doesn't change that so let the pace slow down, shorten your stride, back off the effort, and if it’s a particularly steep hill, walking for a few seconds is absolutely fine.
There is nothing wrong with that.
The goal isn't to protect your average pace.
The goal is to protect the purpose of the session.
Don't Forget the Rest of Your Life
The same easy run can be completely different sessions for two different athletes.
One might have slept eight hours, had a quiet day at work and eaten well. Another might have slept badly, worked ten hours, missed lunch and spent the evening dealing with a family issue.
Same pace. Same route. Very different stress.
That's why I don't coach the watch in isolation. I coach the athlete.
This is an important part of all of this.
Your body doesn't have a magical compartment labelled “training stress.” It has to deal with everything.
A hard run.
A stressful day at work.
A rubbish night's sleep.
A family issue.
Poor hydration.
Long hours.
All those things contribute to the overall load you're carrying.
That's why I don't believe training should be given in isolation.
Your training needs to fit your life. There are weeks when you can handle more and there are weeks when you can't. Easy days become even more important when life is already demanding a lot from you.
Make your easy days easy
A lot of runners think “If I’m capable of running faster, why wouldn’t I?”
Easy isn't a sign that you're unfit, and sometimes running slower is exactly what a fitter athlete should be doing.
The discipline isn't in pushing the pace.
The discipline is in knowing when not to.
This isn't about becoming obsessed with keeping your watch happy. It’s the opposite. It's about being disciplined enough to not chase the number when the number isn't the point.
If today's session says easy, let it be easy.
Your ego might not like the pace.
Strava might not be overly impressed.
Your Garmin definitely won't say “well done” for slowing down.
But your body will know the difference.
And then, when the important session comes around, you've given yourself a much better chance of being ready to do it properly.
That's where the real gains are made. Not from making every run harder but from making the right sessions count.
So, are you really training Zone 2?
Have a look back through your recent “easy” runs and not just the average pace.
Ask yourself:
Did the effort feel easy?
Did your heart rate stay where you'd expect?
Did you have to push the hills?
Were you finishing stronger than you started, or were you gradually grinding your way through the session?
And perhaps the biggest question of all:
Are you training for your next race… or training for your next Strava upload?
Because those two things aren't always the same.
One final thought from me as a coach
We all want to see faster paces.
We all like seeing those little numbers improve.
But your easy run doesn't need to prove anything.
Sometimes the smartest run you'll do this week will be the one that looks the slowest on Strava.
Because you're not training for Strava.
You're training for the athlete you want to become.
And those are two very different things.
Want to know whether your current training zones are working for you?
Your pace, heart rate, training history, recovery and life stress all need to be considered together.
If you're not sure whether your easy sessions are really easy, get in touch. We can look at what your data is telling you and work out whether your zones need adjusting.
