12 lessons from 100 miles, several questionable decisions and an unreasonable number of snacks.
There are plenty of articles about how to train for a 100-mile ultramarathon.
Training plans.
Mileage.
Heart-rate zones.
Strength work.
Fuelling strategies.
Kit lists.
Pacing.
All very useful.
But sometimes what you really want to know is:
What is it actually like?
What happens when you've been running for 12 hours?
What happens when it's dark, your legs hurt and you've still got an absolutely ridiculous distance to cover?
What happens when your stomach decides it's had quite enough of your nonsense?
And what would you do differently if you could go back and start again?
In July 2026, I ran 100 miles from Bamburgh Castle to Edinburgh Castle in the Rat Race Castle to Castle ultramarathon.
One hundred miles.
On foot.
Voluntarily.
I had a training plan, a fuelling strategy, plenty of kit and what I thought was a reasonable understanding of what I'd signed myself up for.
Turns out there's quite a difference between planning to run 100 miles and actually doing it.
There were beautiful moments, difficult moments and probably a few occasions when I'd have happily swapped the entire experience for a comfy chair and a packet of biscuits.
But I finished.
And I learned rather a lot along the way.
I'm not an elite athlete. I'm not trying to win races. I'm just an ordinary woman in my fifties who looked at 100 miles and thought:
"I wonder if I could?"
And then, somewhat stupidly, decided to find out.
So here are 12 things I wish I'd known before running 100 miles.
1. The race doesn't start at the start line
It starts months earlier.
The race itself might take a day or two.
The preparation takes much longer.
The boring runs.
The wet runs.
The tired runs.
The runs when you really can't be bothered.
The strength sessions.
The fuelling practice.
The kit experiments.
The learning what your body does when it gets tired.
That's the real work.
And unfortunately, buying another pair of running shoes doesn't count as training.
I've checked.
One thing I learned is that you don't need every training run to be spectacular. You need consistency, sensible progression and enough recovery to absorb the work you're doing.
Some weeks will go brilliantly.
Other weeks life gets in the way.
Family, work, tiredness, illness — because apparently the rest of the world doesn't stop just because you've entered a ridiculous race.
Training isn't about being perfect.
It's about preparing as well as you realistically can.
What I'd do differently: I'd spend less time worrying about individual runs and more time looking at the bigger picture. Consistency, recovery and practising race-day routines matter more than one heroic training session.
2. Don't chase the excitement at the beginning
The start of a 100-miler is exciting.
Very exciting.
You've trained for months.
You're surrounded by other runners.
Everyone is fresh.
Everyone is optimistic.
Everyone looks suspiciously clean.
And then you're off.
The temptation is to get swept along.
Don't.
You are not being chased by a bear.
Calm down.
One hundred miles is a very long way, and the version of you who'll be moving 50 miles later deserves some energy too.
It's easy to feel fantastic at the beginning and convince yourself that you're going to feel like that forever.
Spoiler alert.
You won't.
Starting conservatively isn't boring. It's sensible.
And in ultrarunning, sensible decisions early on can make an enormous difference later.
What I'd do differently: I'd be even more disciplined about my early effort. No getting carried away because everyone else is moving faster. Run your own race, not someone else's.
3. Pace is not the whole story
I spent a lot of time thinking about pace.
How fast should I run?
What pace will get me to the finish?
How much can I afford to slow down?
But over 100 miles, there are so many variables.
Terrain.
Weather.
Hills.
Aid stations.
Toilets.
Food.
Fatigue.
Sleep.
Navigation.
Your feet. Your feet. Ouch, your feet!
Your stomach.
Your mood.
Your pace will change.
That's normal.
A mile along a lovely flat path is very different from a mile climbing through mud when your legs have already decided they've done quite enough.
Your Garmin may disagree.
Ignore the judgemental little wrist goblin.
Of course, pace still matters when you've got checkpoint cut-offs to meet. But trying to maintain one perfect pace over wildly different terrain is a recipe for frustration.
What I'd do differently: I'd plan around realistic moving speeds, checkpoint cut-offs and time for stops, rather than obsessing over my average pace.
And I'd spend a lot less time looking at my watch wondering why the miles weren't disappearing any faster.
4. Eat before you're starving
This sounds ridiculously simple.
It also becomes surprisingly difficult.
When you're tired, you don't necessarily want food.
When you've been eating for hours, you may not want another gel.
When you're running uphill, eating can feel like hard work.
And when your stomach starts protesting, the thought of forcing anything else down can be deeply unappealing.
But one of the biggest lessons I've learned is that fuelling needs to be a plan, not a vague intention to eat something when you fancy it.
Your body needs a regular supply of carbohydrate during prolonged exercise, along with enough fluid and sodium for your needs and the conditions.
Exactly how much varies, so practise your fuelling during training and build towards an intake you can tolerate.
Don't rely entirely on one food.
Have sweet options.
Have savoury options.
Have things that are easy to eat when you're moving.
My personal favourites include Stroopwafels, Skittles and Scampi Fries.
Not exactly a Michelin-starred sports nutrition menu, but they can be part of a properly planned fuelling strategy.
And remember, what sounds wonderful at mile 10 might be utterly revolting at mile 70.
Your stomach may have very strong opinions.
Unfortunately, it gets the final vote.
What I'd do differently: I'd practise fuelling even more, particularly when tired, and have more alternatives ready for when my stomach decides it no longer supports my lifestyle.
Because if a cheese sandwich suddenly saves your race, don't question it.
Thank the cheese.
5. Your feet need their own race strategy
At some point, your feet are going to have opinions.
And you need to listen to them.
I've experienced blisters during long-distance events, and there's nothing quite like knowing you've got miles and miles left to cover while one particular toe is making its feelings very clear.
By mile 50, your little toe may have formally resigned.
The thing is, small problems can become enormous problems when you repeat the same movement thousands upon thousands of times.
A slight rubbing sensation at mile 15 might be manageable.
By mile 45, it could feel like you're walking on Lego.
Don't wait until you've got a massive blister before doing something.
If something is rubbing, deal with it.
If your socks are wet, consider changing them.
If your shoes don't feel right, don't ignore it.
And test your footwear, socks and foot-care routine during training.
What I'd do differently: I'd have a more deliberate foot-care strategy, carry what I need to deal with hot spots and stop earlier to sort problems before they become a full-blown crisis.
Your feet are doing the actual work.
Treat them accordingly.
6. The middle of the race can be weird
The beginning is exciting.
The end is exciting.
The middle?
The middle is where things can get interesting.
You've been moving for hours.
There's still an enormous distance to go.
The novelty has worn off.
Your body is tired.
Your brain is tired.
And you can't quite believe you're not finished yet.
This is where the mental side of ultrarunning becomes very real.
It's easy to start doing the maths.
How many miles left?
How many hours?
What time will I finish?
Why does the next checkpoint seem to be getting further away?
Why didn't I take up pottery?
But thinking about the entire remaining distance rarely helps.
Instead, make the problem smaller.
Next checkpoint.
Next food.
Next hill.
Next landmark.
Next bit of daylight.
You don't have to run the whole remaining distance in your head.
You just have to concentrate on the next manageable section.
What I'd do differently: I'd have more little mental milestones planned and spend less time calculating the enormous number of miles still left.
One checkpoint at a time.
One biscuit at a time.
Whatever works.
7. Night running is a different sport
Running in daylight is one thing.
Running when you're exhausted and it's dark is another.
Your world becomes smaller.
Headtorch.
Feet.
The runner in front.
The path.
The occasional mysterious noise in the bushes.
Every rustle is either a rabbit or the beginning of a horror film.
And when you've been moving for hours, your brain can start doing some very strange things.
Distances feel different.
Hills seem bigger.
Navigation becomes harder.
And what looked like a perfectly obvious trail in daylight can suddenly resemble six identical paths leading into absolutely nowhere.
Practise running in the dark before race day.
Test your headtorch.
Know how long the batteries last.
Carry a backup and enough power to get through the night.
Practise navigating when you're tired.
And don't rely entirely on your phone.
I learned how quickly phone battery can disappear when you're using it for entertainment over long periods. Not ideal when you also need it for important things.
Music, podcasts and conversation can be brilliant for keeping your mind occupied, provided you can still hear your surroundings and navigate safely.
What I'd do differently: I'd put even more thought into my night-running setup, including lighting, battery management, navigation and how to stay alert when fatigue really starts to kick in.
Because being exhausted, lost and unable to work your technology is a special kind of entertainment.
8. There will be moments when you want to stop
This is probably inevitable.
It doesn't necessarily mean you should stop.
It also doesn't necessarily mean you should carry on.
That's an important distinction.
Sometimes you need food.
Sometimes you need to change clothes.
Sometimes you need to sort a blister.
Sometimes you need a short rest.
And sometimes you need medical help.
One of the things I've learned is that a terrible ten minutes doesn't automatically mean you're having a terrible race.
You can feel dreadful, eat something, adjust your clothing, slow down and suddenly find that things feel manageable again.
But there's a difference between pushing through an ordinary difficult patch and ignoring a genuine warning sign.
If you're injured, confused, unusually unwell or showing signs of a serious problem, stop and seek help.
No finish line is worth risking your long-term health.
What I'd do differently: I'd have a simple checklist for difficult moments.
Have I eaten enough?
Do I need fluids?
Am I too hot or cold?
Do I need to slow down or rest?
Is there a problem that needs proper attention?
And if it's simply a mental wobble, I'd try not to make a big decision about quitting in the middle of it.
Sometimes you just need a biscuit and a word with yourself.
9. The people around you matter enormously
Your support crew.
Other runners.
Volunteers.
People at aid stations.
Random people cheering from the side of the road.
They can make an enormous difference.
A friendly face at exactly the right moment can completely change your mood.
And there's something rather lovely about the ultrarunning community.
People who would normally think nothing of discussing the weather suddenly find themselves having detailed conversations with complete strangers about blisters, stomach problems and how many miles they've got left.
Perfectly normal behaviour.
During my 100-miler, I was also running for Charity, which gave the challenge an extra layer of meaning.
When you're taking on something difficult, having people supporting you and a reason that matters to you can be incredibly powerful.
What I'd do differently: I'd make even more effort to appreciate the people around me and enjoy those little moments of encouragement.
Because you're not just running against the clock.
You're part of something.
And that's one of the best things about it.
10. You don't need to be the fastest person
This is worth repeating.
You don't need to be elite.
You don't need to run every section.
You don't need to look impressive.
You need to keep making sensible decisions.
Ultrarunning rewards patience, consistency and the ability to adapt.
Sometimes the person who looks incredibly comfortable at mile 20 isn't the person who looks comfortable at mile 80.
You're playing a very long game.
And one of the things I love about these events is that you see all sorts of people taking part.
Different ages.
Different abilities.
Different reasons for being there.
Some want to compete.
Some want a personal best.
Some simply want to finish.
All perfectly valid.
For me, the achievement was taking on 100 miles and getting to the end.
Not because I was the fastest.
But because I'd dared to try.
What I'd do differently: I'd spend even less time comparing myself with other runners.
Someone else's pace, training or experience doesn't determine what I'm capable of.
Run your own race.
And keep moving towards your own finish line.
11. Have a plan. Then be prepared to ignore it.
You should absolutely have a plan.
Know roughly how you want to pace yourself.
Know what you intend to eat.
Know where your checkpoints are.
Know your kit.
Know your navigation.
Know the cut-offs.
Have a sensible strategy for rest.
But don't become so attached to your plan that you can't adapt.
If it's hotter than expected, adjust.
If your stomach is struggling, adjust.
If you're feeling brilliant, don't suddenly decide you're going to win the race.
And if you're having a terrible day?
Adjust the goal.
Sometimes the goal changes from:
"I'd like to finish in X hours."
to:
"I'm going to get to the next checkpoint."
That's still progress.
Plan A is lovely.
By mile 60, you may be on Plan F, which mostly involves crisps and stubbornness.
And that's okay.
What I'd do differently: I'd have more flexibility built into my race plan, with clear priorities for fuelling, pacing, kit and rest, rather than feeling everything needed to go exactly as expected.
Because over 100 miles, something probably won't.
And the ability to adapt is part of the challenge.
12. Your finish-line feeling is impossible to explain
After you've spent months thinking about the race, there's something slightly surreal about finally reaching the finish.
You've imagined it.
You've worried about it.
You've planned for it.
You've probably questioned your sanity on several occasions.
And then suddenly...
You're there.
For me, it was Edinburgh Castle.
After setting off from Bamburgh Castle and covering 100 miles, I'd finally reached the end.
I did it.
I actually ran 100 miles.
Whatever my time.
Whatever my pace.
Whatever had gone wrong along the way.
I finished.
And that's a feeling I'll remember.
Not because everything went perfectly.
It didn't.
But because I'd taken on something that once seemed completely ridiculous and somehow made it to the other side.
What I'd do differently: I'd try to enjoy the finish a little more and take in what I'd actually achieved.
Because after spending so long worrying about whether you'll get there, it's easy to forget to appreciate the moment when you finally do.
And that moment is worth appreciating.
So, what would I really do differently?
Quite a lot, probably.
I'd practise fuelling even more.
I'd pay more attention to my feet.
I'd be even more conservative early on.
I'd accept walking earlier.
I'd spend less time worrying about pace.
I'd make sure my night-running kit and battery strategy were properly sorted.
I'd remember that things will almost certainly go wrong, and that's part of the challenge.
And I'd enjoy it more.
Because when you're obsessed with whether you're going to finish, it's easy to forget to look around and realise:
I'm actually doing this.
I'm out here.
I'm covering a ridiculous distance.
I'm seeing places I'd never normally see.
I'm doing something I once thought was impossible.
And even if it hurts, even if I'm tired, even if I've just spent 20 minutes questioning my life choices...
It's still a pretty incredible thing to be doing.
Would I run 100 miles again?
Ask me when my legs work properly.
But here's what running 100 miles taught me.
You don't have to be the fastest.
You don't have to be fearless.
You don't have to be some mythical ultrarunning machine.
You can be an ordinary person who decides to try something extraordinary.
You can be nervous.
You can doubt yourself.
You can have a bad day.
You can walk.
You can eat too many crisps.
You can swear at a hill.
You can wonder what the hell you've done.
And you can still keep going.
That's probably the bit I'll take away from it.
Not just the distance.
Not just the time.
Not just the medal.
But the knowledge that sometimes the best thing you can do is look at something that seems completely ridiculous...
...and say:
"Fuck it. I'll have a go."
KEEP ON SMASHING IT. ❤️
Because you don't have to be extraordinary to do extraordinary things.
[GET THE ULTRA GUIDE]
Have you run 100 miles, or are you thinking about it? What's the one thing you'd most like to know? I'd love to hear from you.