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Half marathon with no training

262 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:
Pileoftrash · 19/07/2026 09:56

I’m with you OP, I feel instinctively that doing this without training is dangerous, and that’s probably because I myself have low-average fitness. I think people who are saying it’s no big deal are likely people who are very fit. My OH hadn’t done any training 3 months before his and I told him he needed to start. To be fair to him he did and he managed the half marathon but it was very hard going and his toenails and feet are still a mess 🤣

USaYwHatNow · 19/07/2026 09:51

I think it depends on his base level of fitness which may not be that great from what you've said of him struggling previously? I absolutely think some of it is about mental stamina. As soon as something feels uncomfortable for me I stop. My ex military husband on the other hand ran an ultra marathon with a week's notice, and yes, had a decent level of fitness but he just seems to have this stubborn mind set which I wish I had 😂 I did cycle the London to brighton route pregnant with 0 training so it can be done!

A bit of training may help but it may also be too late.

MrsAvocet · 19/07/2026 09:51

It's along time since I was a runner, but based on my experience I would say one of two things will proobaby happen here.
1)He will set off far too fast, buoyed by over confidence and the excitement of the day. That will catch up on him fairly quickly and he'll realise his mistake and end up jogging and walking but eventually manage to get to the end. After all, lots of unfit people or people in crazy costumes do complete half marathons and even marathons but it takes them a long time and they need to pace themselves properly.
Or
2)He will set off far too fast, buoyed by overconfidence and the excitement of the day. That will catch up with him fairly quickly but he'll be too pig headed to acknowledge mistake and will plough on. His lack of preparation including his probable lack of a fuelling and hydration strategy will lead to cramp and/or "hitting the wall" and he'll give up.
Hopefully it will be the former.
But I will be very surprised if he completes a half marathon in under 2 hours from what you say. A lot of fairly reasonable regular runners would find that a challenge. There's quite a lot to consider when running that far, not least, your feet. I'd get some blister plasters in if I were you...

BringBackCatsEyes · 19/07/2026 09:46

zurigo · 19/07/2026 09:36

Maybe if they're city ones? I don't recall any loos on ones I've run (in the countryside).

Well OP needs to tell us WHICH half it is so we can come and watch check out the loo situ!

Ethelspagetti · 19/07/2026 09:41

Running makes the body want to poo so combining it with coffee is a terrible idea! Tell him if he struggles then to walk it. He’ll be fine walking it!

EarringsandLipstick · 19/07/2026 09:40

MabelEstherAllen · 19/07/2026 09:37

I do ultra-marathons: I’ve done around 50, plus lots of regular marathons and a ton of half-marathons. I don’t really understand why he wants to do this, to be honest. He’s highly unlikely to enjoy it. It’s just arrogant and frankly disrespectful to the demands of distance running. He reminds me of the men (and they were all men) who were featured on a Jeremy Vine show a few years ago, themed around people who ran a marathon on no training. Most got round eventually, but some picked up lifelong injuries. If he’s set on doing this then, ideally, I’d say that he needs to have a good running pack, so that he can fuel and hydrate his way around and not be reliant on checkpoints. He’ll need salt tablets. If he just drinks a ton of water and doesn’t take salt tabs, he’s at risk of hyponatraemia. No ibuprofen before, during or after the race: it puts too
much pressure on the kidneys. And the coffee is a dreadful idea: he’ll shit himself and the caffeine will wear off about an hour in, leaving him feeling even worse. He’ll likely finish, but in pain and in a foul mood and possibly with long-lasting injuries. If his current 5k time is 35mins, I can’t see how on earth he’ll finish in sub-2hrs. As I say, I can’t see why he’d want to do this. There’ll be no joy, and where’s the sense of achievement, if he hasn’t trained for it?

💯 this.

I’m always supportive of anyone doing any competition or race - if they have trained. Even if they have to go slow, take breaks etc - they’ve done the preparation, it will be an achievement and they’ll be fine.

Egotistical men (it’s always men) doing silly things like this is just a waste of everyone’s time.

ACynicalDad · 19/07/2026 09:37

You should see some oriole that get around the marathon, he may not break any records but if he’s not carrying half a hippopotamus around his middle is just a half, he’ll be fine.

S89 · 19/07/2026 09:37

BringBackCatsEyes · 19/07/2026 09:35

It’s in 2 weeks time.
The training ship has sailed!

Ah I missed that bit! He could probably squeeze in a 10 miles but not too close to the date!

MabelEstherAllen · 19/07/2026 09:37

I do ultra-marathons: I’ve done around 50, plus lots of regular marathons and a ton of half-marathons. I don’t really understand why he wants to do this, to be honest. He’s highly unlikely to enjoy it. It’s just arrogant and frankly disrespectful to the demands of distance running. He reminds me of the men (and they were all men) who were featured on a Jeremy Vine show a few years ago, themed around people who ran a marathon on no training. Most got round eventually, but some picked up lifelong injuries. If he’s set on doing this then, ideally, I’d say that he needs to have a good running pack, so that he can fuel and hydrate his way around and not be reliant on checkpoints. He’ll need salt tablets. If he just drinks a ton of water and doesn’t take salt tabs, he’s at risk of hyponatraemia. No ibuprofen before, during or after the race: it puts too
much pressure on the kidneys. And the coffee is a dreadful idea: he’ll shit himself and the caffeine will wear off about an hour in, leaving him feeling even worse. He’ll likely finish, but in pain and in a foul mood and possibly with long-lasting injuries. If his current 5k time is 35mins, I can’t see how on earth he’ll finish in sub-2hrs. As I say, I can’t see why he’d want to do this. There’ll be no joy, and where’s the sense of achievement, if he hasn’t trained for it?

sunallsummer · 19/07/2026 09:37

Newname26 · 19/07/2026 09:34

Whats the worse thing that could happen? Sore feet and take longer than planned?

According to Google - rhabdomyalisis!

OP posts:
northernballer · 19/07/2026 09:36

sunallsummer · 19/07/2026 09:21

I know a few people have commented saying they know someone who did the same without any training but then in their comment they go on to say actually they were a PT or a football player or something so it’s not like they’re starting from zero, they might not have running training but they just have a great level of fitness already

I’d say my DH is just normal level. He’s not unfit but not fit either. I think his 5km was around 35 minutes. He got the 2hr for the half marathon by thinking he could shave off some time from his 5kn then multiplying it by 4

This is a terrible way to calculate your time! My best 5k is 19.19 (yes I am still smug) and my best half is 1.42 with training, you get slower not quicker.

I think he'll get round but he'll walk most of it and then say he was on for a sub 2 but he pulled something, men do this all the time.

Please let us know how he goes!

Morepositivemum · 19/07/2026 09:36

Myself and dh did this, it was tough and we had to walk a lot but we knew we weren’t ready and so walked when we had to. Sun cream and hydration and tell him to stop when he has to but make sure to keep going as finishing is amazing but also to especially pace yourself at the end

zurigo · 19/07/2026 09:36

BringBackCatsEyes · 19/07/2026 09:34

Most larger ones will have loos along the route.

Maybe if they're city ones? I don't recall any loos on ones I've run (in the countryside).

BringBackCatsEyes · 19/07/2026 09:35

S89 · 19/07/2026 09:34

I am a runner and have ran numerous halves and several marathons. I would say it's doable, but highly unlikely he will get anywhere under two hours. He should try and train as much as he can though and get a long practice run in. My biggest pieces of advice:

  1. Get some decent running shoes, loads of new runners cheap out on this and then get injured. I use Mizuno Wave riders, which are very reasonably priced and provide great support.
  1. Eat plenty of carbs and proteins (something like chicken pasta the night before), a high protein breakfast (my go to is poached eggs and spinach).
  1. Absolutely do not drink loads of coffee/ try any workout supplements he's never tried before, he will be cramping/ shitting through the eye of a needle. SIS electrolyte tablets are good for a bit of a boost pre race though, one before a run normally works for me and you can also get electrolytes chew bars. Lots of runners like energy gels but personally, I think they are disgusting and am yet to find one I like that sits well, after over a decade of running.

Good luck!

It’s in 2 weeks time.
The training ship has sailed!

Youspurnme · 19/07/2026 09:35

Hahahaha a sub 2 hour half marathon with no training 😂😂😂 👍 he will end up walking most of it in between stops to shit because of all the coffee. And those portaloos are…something.
He may well finish eventually but if he starts off too hard there’s a good chance of DNF. Oh well, please come back and let us know how he gets on!

TisEye · 19/07/2026 09:35

Not read all the replies but I'd make sure he has his phone and make sure your volume is up for when he calls for you to collect him from mile 6 when his energy will be spent.

I've done 3 half marathons when a fit, regular runner and they are draining & require prep if you're not running decent distances regularly.

A completely different beast than a 5k which anyone with ok fitness could do.

EarringsandLipstick · 19/07/2026 09:35

sunallsummer · 19/07/2026 09:29

Sorry, I’m probably being really stupid here but with the heat being an issue will that only be if he runs too fast at the start? Or is that likely to be an issue just doing the run in general if it’s a hot day?

thanks for the advice (and thanks to everyone else on here too) x

Heat makes everything hard. I’m very fit and an experienced runner - days when I’m competing / running in hot weather are very tough, even having trained. You need to adjust your hydration plan and increase gels etc due to sweating, and especially the loss of sodium. (I’m in Ireland so clearly we don’t cope well with the (usually rare!) heat).

So if he’s not ready for the race and it’s a hot day, he may well collapse or faint. It’s not uncommon. First Aid will be available but it’s not ideal.

BringBackCatsEyes · 19/07/2026 09:34

zurigo · 19/07/2026 09:34

Yeah, I've seen people talking about having a double shot of espresso before a workout as it boosts your workout - and that's okay - gyms have toilets. A half marathon course? You'll get toilets at the start/finish, but rarely otherwise.

Most larger ones will have loos along the route.

S89 · 19/07/2026 09:34

I am a runner and have ran numerous halves and several marathons. I would say it's doable, but highly unlikely he will get anywhere under two hours. He should try and train as much as he can though and get a long practice run in. My biggest pieces of advice:

  1. Get some decent running shoes, loads of new runners cheap out on this and then get injured. I use Mizuno Wave riders, which are very reasonably priced and provide great support.
  1. Eat plenty of carbs and proteins (something like chicken pasta the night before), a high protein breakfast (my go to is poached eggs and spinach).
  1. Absolutely do not drink loads of coffee/ try any workout supplements he's never tried before, he will be cramping/ shitting through the eye of a needle. SIS electrolyte tablets are good for a bit of a boost pre race though, one before a run normally works for me and you can also get electrolytes chew bars. Lots of runners like energy gels but personally, I think they are disgusting and am yet to find one I like that sits well, after over a decade of running.

Good luck!

sunallsummer · 19/07/2026 09:34

PosiePerkinPootleFlump · 19/07/2026 09:31

"He got the 2hr for the half marathon by thinking he could shave off some time from his 5km then multiplying it by 4"

😂cocky sod. If he couldn't do 5km in 30 minutes there's not a hope in hell he can do 4x 5km in 30 mins each (and an extra 1.1km to boot)

I'm sure he will survive the experience, but it will take him way longer than 2 hours and it will really hurt both during and after. I'm sure he'll have an excuse about 'the heat' or 'an upset stomach' (from all the coffee) which stopped him achieving his sub-2 dream....

Haha! He would say in fairness he was slowed down by all the other slow runners and that stopped him reaching his under 30min 5km goal😂😂😂 I saw him during it and that absolutely was not the case hahaha

he’s a great guy and takes a good joke against himself 👍🏼 I’d love to see him make his target time but if not he’ll definitely take some gentle teasing against himself about how it was the heat/the shoes/the blisters/the other runners that stopped him winning the entire thing 😂🙈

OP posts:
Newname26 · 19/07/2026 09:34

Whats the worse thing that could happen? Sore feet and take longer than planned?

zurigo · 19/07/2026 09:34

sunallsummer · 19/07/2026 09:30

Great- I’ll pass that on to him 👍🏼 definitely sounds like coffee would be bad! We have a friend who goes to the gym a lot and uses pre workout so I think that’s where he’s got it from 🙈

Yeah, I've seen people talking about having a double shot of espresso before a workout as it boosts your workout - and that's okay - gyms have toilets. A half marathon course? You'll get toilets at the start/finish, but rarely otherwise.

TheClocksFast · 19/07/2026 09:33

I used to have a partner who was seriously into running. One time he was doing a cross-country race and several people turned up ‘unprepared’. One guy just had a normal pair of office shoes on. Needless to say he didn’t last long 😂

OP, I’m sure if there is a lesson to be learned here, your partner will learn it.
Also, can’t wait to find out how he gets on…

BringBackCatsEyes · 19/07/2026 09:33

I’m mean you can’t decide to run really fast to get round in under 2 hours if your body isn’t able. Sure, there is a lot of mental strength needed, but in conjunction with a body that is capable.
We’ve all heard about dads’ race at sports day where grown, overweight men who haven’t so much as run to chase down a loose trolley in a supermarket car park THUNDER down the track. You can’t do that for longer distances. Does he think caffeine will give him bionic powers? If he struggled with a 5k why does he think he’ll be ok over 13 miles?
I do hope it motivates him to train to run one properly. It’s a distance that doesn’t dominate your life like marathon training does.

Enko · 19/07/2026 09:32

sunallsummer · 19/07/2026 00:47

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

You are.not being dramatic. It is not dramatic to care about the people we spend our life with.

I agree with @Kerri126 in what's likely going to happen.

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