Help protect children from gaming harms.

Take our survey

Please or to access all these features

AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Half marathon with no training

232 replies

sunallsummer · 19/07/2026 00:42

Probably a stupid question sorry but I’m not a runner so have no idea!

DH impulsively signed up to do a half marathon in 2 weeks and has done zero training for it. He’s slim and has normal fitness I would say but definitely not a runner and previously did a 5km and completed it but struggled

I know it’s his choice and he’s an adult to it’s up to him, but I’m just a bit worried about the idea of him running 21km with little to no training. I’m just not sure if I’m just being overly anxious but it seems so far to my non runner brain! Having said that, I know people do 10km without any real training and it’s fine, has anyone ever done a half marathon without any training and did it go ok?!

My concern is when he puts his mind to something he can be very stubborn and competitive so I think when the run starts he’ll actually go much faster than he should and it’s not like he’ll accept he’s not trained and take it at a slower pace. His plan was to drink a few coffee and get some pre workout for it and frankly I’m worried he ends up unwell after it

If anyone who knows anything about running can put my mind at rest and reassure me that I’m being silly and dramatic and he’ll be fine (other than a normal amount of tiredness afterwards) I’d really appreciate it!

OP posts:
PollyBell · 19/07/2026 00:44

He is a grown man of course you are being silly and dramatic

TheLightSideOfTheMoon · 19/07/2026 00:46

Ah, let him crack on.

I thought I couldn’t walk up some steps earlier (I’d been in the sea for three hours and my legs forgot how to operate and I was hungry). I still did it. I got to the top.

I’m sure he’ll be dandy.

RubyFlax · 19/07/2026 00:47

Well it’s not ideal, but he is where he is now. Can he comfortably walk 13 miles ? If so he can do a half marathon, he just needs to set off very steady and jog / walk / jog / walk intervals throughout.
I’ve done a half with very little training by doing the above.
The worst thing will be to set off trying to “run” and risk hurting himself or completely running out of fuel.
Also loads of coffee is a terrible idea !?

sunallsummer · 19/07/2026 00:47

PollyBell · 19/07/2026 00:44

He is a grown man of course you are being silly and dramatic

i know he’s a grown man and I can’t stop him, just wanted a bit of perspective on it because I literally have zero clue about running and what’s far and what’s not far (it all sounds far to me tbh!) so just wasn’t sure! Good to know I’m just being dramatic about it

OP posts:
sunallsummer · 19/07/2026 00:48

TheLightSideOfTheMoon · 19/07/2026 00:46

Ah, let him crack on.

I thought I couldn’t walk up some steps earlier (I’d been in the sea for three hours and my legs forgot how to operate and I was hungry). I still did it. I got to the top.

I’m sure he’ll be dandy.

Ah good point! Thank you x

OP posts:
sunallsummer · 19/07/2026 00:48

RubyFlax · 19/07/2026 00:47

Well it’s not ideal, but he is where he is now. Can he comfortably walk 13 miles ? If so he can do a half marathon, he just needs to set off very steady and jog / walk / jog / walk intervals throughout.
I’ve done a half with very little training by doing the above.
The worst thing will be to set off trying to “run” and risk hurting himself or completely running out of fuel.
Also loads of coffee is a terrible idea !?

I think he said it’s to make him go faster?! He wants to get less than 2 hours! He’s ambitious haha I’ll give him that

OP posts:
RubyFlax · 19/07/2026 00:52

sunallsummer · 19/07/2026 00:48

I think he said it’s to make him go faster?! He wants to get less than 2 hours! He’s ambitious haha I’ll give him that

The only thing that will go faster if he drinks a load of coffee before a run is his digestive transit time, so if he plans on shititng himself by mile 3 then crack on 😂

Coffeeisnecessary · 19/07/2026 00:52

Less than 2 hours with no training is mad to me and I'm a runner. I'm slow though so maybe my view point is wrong! If he can run 5k he has good general fitness but a half marathon is hard. I've done loads of 10k but only one half as I found it quite gruelling. Hopefully he will be fine and listen to his body and not push it.

wombat1a · 19/07/2026 00:58

Sub 2 hrs with no training - I would say not a chance. DH signed up for a 10k run when he was around 40. At that point he was still playing 11-a-side football 2x a week, and cycling around 2x 40 miles rides a week, then spend around 6 wks 'training' for the 10k. He managed the 10k run in around 1hr:10 but was really sore for a week afterwards. Talking to him he reacons he could have walked the 21k but for jogging it - not a chance.

Zfactorstar · 19/07/2026 00:59

He'll be fine. You can walk in marathons, loads of people do, and if it gets to be to much you can quit. Even elite runners sometimes have to stop for whatever reason.

doobopdeboo · 19/07/2026 01:03

To be honest, OP, he sounds like a cocky idiot.
Im sure he’d be able to walk 13 miles, so he’ll be able to get to the end. But to say he’s going to drink coffee to help him go faster and to aim for under 2hrs is just delusional.
I’ve done a couple of half marathons. I was running 5k several times a week for quite some time before I started training for them and I still found them tough. Right now, I think I could run 5k at at push but it’d be hard, even though I’m fairly fit and active, cycle lots etc.
One of the key things you learn from the training plan is how to pace yourself. I’d be worried that your DH will go off like a rocket then come crashing down to earth, possibly literally!
He is an adult and he has to make his own decisions, but that doesn’t mean you have to agree with him and on this one I think you’re right and he’s very wrong!

doobopdeboo · 19/07/2026 01:05

Zfactorstar · 19/07/2026 00:59

He'll be fine. You can walk in marathons, loads of people do, and if it gets to be to much you can quit. Even elite runners sometimes have to stop for whatever reason.

Yes but this idiot wants to do a sub 2hr fuelled by coffee…

ReyRey12 · 19/07/2026 01:06

Im sure he can finish half marathon but doing it under 2h is very ambitious. There is no need to be anxious, can't really see what could go irreversibly wrong.

BringBackCatsEyes · 19/07/2026 01:07

Sub 2 is just over 9 min/mile.
That’s a pretty decent pace for an intermediate runner who has trained.
I don’t rate his chances tbh, but if he’s of regular fitness I’m sure he’ll get round somehow.

Duckagogo · 19/07/2026 01:08

sunallsummer · 19/07/2026 00:42

Probably a stupid question sorry but I’m not a runner so have no idea!

DH impulsively signed up to do a half marathon in 2 weeks and has done zero training for it. He’s slim and has normal fitness I would say but definitely not a runner and previously did a 5km and completed it but struggled

I know it’s his choice and he’s an adult to it’s up to him, but I’m just a bit worried about the idea of him running 21km with little to no training. I’m just not sure if I’m just being overly anxious but it seems so far to my non runner brain! Having said that, I know people do 10km without any real training and it’s fine, has anyone ever done a half marathon without any training and did it go ok?!

My concern is when he puts his mind to something he can be very stubborn and competitive so I think when the run starts he’ll actually go much faster than he should and it’s not like he’ll accept he’s not trained and take it at a slower pace. His plan was to drink a few coffee and get some pre workout for it and frankly I’m worried he ends up unwell after it

If anyone who knows anything about running can put my mind at rest and reassure me that I’m being silly and dramatic and he’ll be fine (other than a normal amount of tiredness afterwards) I’d really appreciate it!

How old is he? My ex husband's brother decided to run a full marathon, he did train, he had a heart attack. They said he was lucky he collapsed at one of the first aid tents as the defib is the reason he lived. He had to retire has undoubtedly shortened his life span and will be on meds forever now. He was in his 50s when he did this, but appeared slim and fit.

Of course it's not, in any way, strange to be concerned about foolishly trying to run a half marathon with no clue or training.

Chances are he'll probably be fine, but you're not foolish at all to be worried.

suki1964 · 19/07/2026 01:17

If its any help, Im a non runner and as a seriously overweight 59 year old, having had covid the week previously only getting the all clear the day before, I did a 13 mile charity hike - roads, beaches, cliffs, steps etc and survived.

Took me 4 hours though and that was walking

If it's an even surface and hes in reasonable health , he will be fine. Only I would skip the coffee and make sure Ive a light breakfast and some protein snacks and jelly babies with me - as well as loads of fluids

Gateappreciation · 19/07/2026 01:31

He’ll end up walking a lot of it, rather than running it. If he struggles to do 5k, he’s not going to be able to do 21k, especially if warm.

canklesmctacotits · 19/07/2026 03:54

Are there any hills? He won’t be able to complete it in under 2hrs on the basis of your description of his fitness. He’ll probably do a combination of setting off crazy fast, slowing down, walking, gearing up, running, walking etc. It’ll be mentally gruelling because hea underestimated how far 13 miles is, and I’d expect him to be in a bad mood afterwards 😂. Just try not to have an “I told you so!” face at the finishing line!

Do come back and let us know how he gets along 😉

Livinginvnam · 19/07/2026 04:42

Can he do it? Yes. Can he do a sub 2 hour? Doubtful. Should you be worried? Not unless there's something missing from your info such as he has recently had a coronary by-pass.

kiwiflan · 19/07/2026 04:43

Please come back and tell us how he got on. As a fit person who’s done a few half’s after a bit of training I think he’ll struggle. He will be able to walk it but I suspect that’s not going to be good for his ego.

Piesy · 19/07/2026 04:49

Please report back on how he gets on 😁

Scarydinosaurs · 19/07/2026 05:06

what time did he do 5k in? You say he struggled, but was it a 30 min struggle, or a 20 min struggle?

Does he do other sports? It’s hard to gauge his fitness from what you’ve said.

Somnambule · 19/07/2026 05:07

He's a cocky idiot and he's probably going to shit his pants, but it won't do him permanent harm and will hopefully teach him a lesson. There's a reason people train for these things.

TwoLeftSocksWithHoles · 19/07/2026 05:08

Get him a banana suit to wear, then he can pause and chat to spectators, stop for selfies etc.

It also has the benefit, should he come last, that he can tell everyone he was only doing it for his Granny as "it's what she would have wanted".

Kerri126 · 19/07/2026 05:59

I’m all for people challenging themselves to go further but half marathons are physically a lot harder than most people think, especially in hot weather.

He’ll likely make it round but with some of the following ticked;
a lot of walking
a slow time
something that needs a trip to the medical tent - think blisters, bleeding nips, upset stomach/puking, dehydration or hyponatremia
a lot of complaining after (lucky you)
feel crap for a while after (also lucky you)
wanting to do another one to right the wrongs

Swipe left for the next trending thread