Can I Still Run This Marathon with a Two Week Setback?

I am planning on running a marathon (1st one) two months from now. I am an experienced runner with a half marathon PB of 1:36. My weekly long runs are up to 25km and total weekly kms is 40-50.

Problem is I am booked to have a nose operation which takes two weeks to recover from – no running.

I am planning on walking my weekly kms during this two week setback but am not allowed to get my heart rate up.

That leaves 9.5 weeks to prepare for the marathon.

Can I, do I?

If so – would my time be affected badly?

Should I just run the half marathon – and put off the full event till later in the year?

– Jeremy

Answer by Dom: Hi Jeremy, this nose operation comes at an inconvenient time, but with a 25k long run and a 1:36 half already banked, two weeks off won't derail your first marathon. The bit that needs care isn't the fitness loss – it's how you come back into training afterwards.

Here's what I want to cover:

1. Why two weeks off costs you far less fitness than it feels like
2. How to ease back in without trying to "catch up"
3. Your 9.5-week build to the start line
4. Finishing versus chasing a time

Why Two Weeks Off Costs You Less Than You Think

Aerobic fitness doesn't evaporate in a fortnight. For an experienced runner with your base, the structural adaptations that make you fast – capillary density, mitochondrial density – hold up well for around two weeks of reduced training; they don't start fading until closer to the three-week mark. What does shift earlier is plasma volume, which can nudge your easy-pace heart rate up slightly and take a little zip out of your legs, not your engine, just some muscular power and running-specific conditioning.

Two weeks is roughly my comfort threshold for exactly this reason. Beyond that, the losses start compounding and I'd be having a different conversation with you. But at two weeks, with your history behind you, you're not starting again – you're picking up.

How to Ease Back In Without Trying to Catch Up

This is the part I'd flag hardest. The temptation after any setback is to jump straight back to where your training plan says you "should" be – in your case, back onto 40-50k weeks and a long run pushing towards 25-30k in week one back. Don't.

Your legs will have lost a bit of their tolerance for pounding the pavement, even if your heart and lungs haven't lost much at all. I'd give yourself about a week of easy running to rebuild that tolerance before loading up again. Something like:

• Days 1-3 back: easy runs of 5-8km, well below marathon effort – think conversational, not laboured
• Days 4-6 back: build towards 8-10km easy, maybe one gentle progressive run where the last kilometre or two lifts to easy-marathon effort
• By day 7-8: back to a normal training week, long run included

Your walking during the two weeks helps here – it keeps some load going through your legs and means this re-entry week won't feel like starting from scratch. Just don't let the walking tempt you into thinking you can skip the easy re-entry running once you're cleared. Listen to your body on this one; a niggle here costs you far more than the week itself.

Your 9.5-Week Build to the Start Line

Take out that one-week re-entry and you're left with roughly 8.5 weeks to build through, taper included. That's enough. Here's roughly how I'd shape it:

• Week 1 (re-entry, covered above): easy running only, building back to normal volume
• Weeks 2-6: consolidation weeks at 40-50k, long run building from 25k back up towards 28-30k
• Weeks 7-8: peak long runs of 30-32km, once or twice, at easy-to-steady pace
• Final 1.5-2 weeks: taper – cut volume, keep a little intensity, arrive fresh

That gives you a real build, not a scramble. You'll hit the start line with a long run of 30-32k behind you, which for a first marathon is exactly what you want.

Finishing or Chasing a Time?

Here's the honest bit. Your 40-50k weekly mileage is decent – it will get you to the finish line comfortably. But it's on the low side if you're chasing a fast time.

Based on your 1:36 half, my Race Conversion Calculator would put you at around 3:20 for the marathon – but only with the training volume to match. 3:20 is roughly 4:44 min/km, held for 42.2km straight. That's intense pacing for someone doing about that distance across an entire week.

I wouldn't chase 3:20 off this build, setback or no setback. I'd aim for 3:45-4:00 instead, run it sensibly, and bank the experience for your next one when you can build mileage further. Have a look at the Marathon Training Tips page for more on structuring that future build.

As for dropping down to the half and delaying the full – I don't think you need to. Your base is solid, your re-entry plan is sensible, and 8.5 weeks of real training is plenty. Go for the marathon.

Best of luck with the operation, the recovery, and the training ahead.

Kind regards,
Dom

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