How I Became a Sub-40 Minute 10K Runner in 6 Months (After 10 Efforts)

A runner smiles on a stormy running track after running 10k in under 40 minutes

Most stories that start with “It was a dark and stormy night” promise to deliver a lot from the start. They can also have the potential for an anticlimax and even cause a bit of an ‘ick’ response to those privy to the storyteller’s love for the dramatic hook. 

Still, this was the poetic and romantic backdrop of me finally running 10 kilometres in under 40 minutes at the tenth time of asking, squeezing into the sub-40 10k club by 12 seconds with a time of 39:47. 

I sprawled out in one of the deep puddles that I had been rampaging through during my all-out effort in the thunderstorm and burst into a hysterical laugh as a nearby soldier of the Thai army kindly handed me a banana, Red Bull, and a bottle of water with a quintessential Thai smile.

In this post, I’ll explain why I gave such a f**k about this particular time, the highs and the lows of enduring a double-figure attempt and, of course, any tips for people like myself who have plateaued around this time and want to shake off the shackles of doubt and make a sub-40 minutes 10k run happen with some planning and prepping.

Why Running a Sub-40 Minute 10k Mattered To Me

Running a 10k in 40 minutes might seem slow to some people, but it may seem impossible for others. For myself, who is a 40-year-old man who looks after himself after a long time of not, this challenge indeed fell into the category of:

  • The goal is big enough to intimidate me.
  • The goal is difficult enough for me to doubt myself whether it’s possible or not.
  • The goal requires a structured dedication that will force me to be better, train harder and build mental resilience to make it happen.

This easy three-step questionnaire works well for me and keeps me honest. It’s what made me run a 5k in under 19 minutes for the first time three months ago, and it’s what got my 10k goal nailed down in the end. 


Before I decided to aggressively attack my running portfolio this year, I wrote down goals for the 5k, 10k, 15k, half marathon, and marathon. Running a sub-40 10k felt like a true milestone and a hat tip to me that I was on the right track for not just running but also my heart health.

Cardio is (thankfully) making a comeback in the fitness world. I was always a groupie and never swayed away from its importance when aiming to live a healthier, high-value.

My Ten Failed Attempts of Running a 10k in Under 40 Minutes 

I’ll quickly discuss each failed attempt, what was going on in my mind, body, and spirit at the time, and what I did to make it happen on the tenth try. Each failed attempt is linked to my Strava activity, where you can check out further metrics of each run, or even give me a follow if you’re on there.

My aim is to show people that consistency is the key factor to achieving fitness goals and that half of the battle is showing up, trying your best on the day, and going after it even when you feel like it’s not your day.

This sounds a bit like cookie-cutter advice, but as we live in such distracting times thanks to the rectangle of chaos that we carry in our pockets most days and instant access to social media, where the comparison to others is rife, I often feel it’s better to go back to the old drawing board and remind ourselves of simplistic notions like this.

Failed Attempt #1 – 40:45

Attempt number one

I got the party started with a 10k personal best (although my Garmin watch did not record this achievement on my profile, grrr), and I thought to myself, “Wow – I’ll get the sub-40 10k very soon, maybe on the next run!”

Of course, I was very wrong; this run gave me severe delusions of grandeur. I ran the first 5k in under 20 minutes and started to gas out on lap number seven; however, I figured that if I could run half of it under 20, then, indeed, I could run the second half of the race again at the same pace.

Child-like naivety or misplaced arrogance?

I put it down to me being drunk on runner’s high, I knew deep down that the 10k was a very different beast to my 5k plan and that my stamina had to improve significantly.

Failed Attempt #2 – 44:41

Attempt number 2

Oh my, it’s all gone a bit tits up in sub-40 10k land.

After getting 46 seconds away from my goal at the first bite of the cherry, my second attempt was woeful, and I slowed down by 4 minutes!

I remember this run well. I had an awful stitch from the third lap. I was stuck in my head, and my legs felt like lead. Neurotic, self-defeating thoughts took precedence over my focus on form and breathing tempo, and I couldn’t wait for it to be over.

The meek shriek of a newborn kitten had replaced the Eye Of The Tiger. “Piss off”, I muttered to myself as I hobbled over to my bike.

A few days after this, I decided to do my annual no-alcohol-for-100-days challenge. I do it every year, and I feel fantastic as much as I miss the taste of red wine. On top of that, I decided to exercise twice daily (with a priority on running), meditate for 20 minutes daily, and journal in the evenings.

I needed my mind to be as clean and focused as possible to complete this before the clock ran out in three months.

Failed Attempt #3 – 40:38

third failed attempt

Boom! Back in business, baby.

A Strava personal record for running 10k, and the first 5k was my third-quickest recorded 5k time. After my last performance, I had won back some dignity and respect for myself and no longer had to worry about letting down the souls of my ancestors.

At one point, I may have even looked in the mirror and smiled unironically. 

In my sub-19 5k piece, I joked that part of my success was my obsessive quest to beat Mark Zuckerberg’s personal best over 5 kilometres. Well, I had beaten him twice at this point, and I fully intended to make that third time lucky.

Your move, Zuck.

Failed Attempt #4 – 42:13

Attempt number 4

This was another run when I felt I was just not in control. I never really got out of the blocks, and my pacing was poor from early on.

This challenge is soul-destroying when one of your kilometres is in the high 4s. I can cope with 4:05 or even 4:09 now and then, as I am up for a last-minute lung-busting effort, but if your body is slowing down and your heart is speeding up, and you see a high 4 around the halfway point, a big part of you knows it’s over, and you just have to continue giving it your best.

An extra frustration on this challenge was my awful sleep quality; I tried my best with my surroundings to fix this and failed miserably.

Failed Attempt #5 – 41:35

Attempt number 5

My fifth attempt also was “nothing to write home about.” After a stressful house move, burning off all sides of the candle, working out twice a day, and sleeping dreadfully, I wondered if I had taken on too much at once.

Doubt is not your friend when you’re aiming for a timed goal, and halfway through this run, I was painfully aware that tonight wouldn’t be my night.

Failed Attempt #6 – 41:15

Attempt number 6

England was playing in the quarter-finals of the Euros, and I believe their kick-off time was around 1 am, so I opted to run later than usual when the sun went down.

One thing that I am 100% sure of and will die on the hill about is that people not born in hot and humid countries are at a colossal disadvantage running a race in a tropical climate. I’ve done about as much heat acclimatisation as anyone can and split-tested this—I am considerably faster at a distance when I run in colder climates.

That said, I can’t complain because I love where I live, and these are the cards I dealt to myself.

Even though the run was not as close as the failed attempt #1 (40:45) and failed attempt #3 (40:38), this did feel less brutal a few degrees lower at 27 degrees Celsius, and I figured I would do this again if I had to stay up late for a sporting event.

Lap number seven had become my hex, and this was the lap where I knew that I had not quite made the grade for running a 10k in under 40 minutes.

Failed Attempt #7 – 43:17

Attempt number 7

The fact that the time for my sixth lap started with a number 5 should be enough to tell you how this one went and how I felt.

Still, I licked my wounds at home and reflected on the last seven attempts. The truth is I was overtraining and under-resting. I already announced the twice-a-day workout goal, and I don’t like quitting just because things are hard. Hard times have created strong mentalities if people see things through to the end since the dawn of time.

Giving up easily is not the man that I want to be.

A good argument against this way of thinking is that quitting something detrimental to you is a sign of strength, acceptance, and maturity. I have had to quit business ideas when they weren’t working for me, left romantic relationships that were no longer making me happy, and even stopped climbing mountains for a while after my Aconcagua saga.

I found all those decisions to “give up” painstaking, but they were also the right thing to do at the time.

Both ways of thinking are excellent philosophies, so I met in the middle. Instead of lifting weights and running every day, I alternated the two, added some regular yoga and Zone 2 recovery sessions on my Air Bike on days I wasn’t running.

This decision was a major needle-mover in successfully running a 10k in under 40 minutes.

Failed Attempt #8 – 40:59

Attempt number 8

I squeezed into the 10k total time, starting with the number 40 for the first time since failed attempt number 3, and by one measly second, I was over the moon.

I was still sleeping like a man on death row, but rearranging my workout schedule to train smart and not like a hardcore lunatic with a revenge arc movie backstory definitely paid off for my faster running time. 

I could almost feel my central nervous system thank me as it regenerated from all of the abuse I had given it over the weeks since announcing my two-workouts-a-day and no booze for 100 days challenge on top of my sub-40 10k challenge.

I had to repent for my active rest workouts by reciting seven Hail Marys to a life-sized poster of the Lord and Saviour of distance running David Goggins for not staying quite hard enough.

Forgive me, David, for I have sinned.

Failed Attempt #9 – 40:32

Attempt number 9

Today was a good day.

England may have lost in the Euros final that morning, but I decided to take my shiny new Nike Vaporflys out for a spin with another all-out effort. The earlier morning meant less heat and humidity from the brutal Thai sun, and with my dialled-in new fitness routine, I had more of a spring in my step. 

Thirty-three seconds from glory and a new Strava 10k personal record. I regained my confidence in my running ability and felt like running a sub-40 10k was more like a possibility.  

SUCCESSFUL Attempt #10 – 39:47

sub-40 10k splits

As the start of this article alluded to… it was a dark and stormy night!

Some people avoid running in the rain, let alone a storm… not me. I love it. There’s something paradoxical and poetic about the hidden beauty in this environment’s misery —dare I say… romantic.

I’ve run in the cold, wet and windy Scottish Highlands during a storm and harsh winters in Bavaria, and I have run many miles in Thailand. The rain can be a blessing when you run long distances in the tropics, especially for me, who has been running in the heart of Thai summer.

I’ve learned a lot about heart rate training this year. Running long distances in extreme heat can wreak havoc on an individual who knows their usual pace at a specific heart rate. Trying to mimic those numbers in an extreme environment is a fool’s errand, but one thing that’s for sure is rain cools your core body temperature down when you’re running, which means you have more energy to put into a fast run.

Rainstorms do not mess around in Thailand, so when they come down, they come down hard and fast. A negative for me was that I had to kick more with the puddles accumulating on the track and combatting the occasional heavy gust of wind. Still, as you can see from my splits, I was flying in the first 5k, beating my arch-nemesis Mark Zuckerberg’s personal record for the third time.

I slowed down on lap number six and seven to 4:05 and 4:06, respectively, but I had done enough to still be in with a shout if I carried on kicking through those puddles as the rain hit my grateful, grimacing face.

Thai soldiers were taking down a canopy on the running track, so I had to keep hurdling over rogue bars and running around them. I could have done without the extra obstacles, but something about it spurred me on more.

Thai people are lovely, and the guys were shouting “sua-sua,” which translates to English as “keep fighting!” I fought on during lap seven, which had become my superstitiously bad luck number. Although it started with a number 4, it wasn’t a high 4, and I knew I had to kick on and push through the fatigue for the final two kilometres. 

I knew it would be tight on my final lap as number 9 showed up on my watch as 4:09. I started doing unhinged maths in my head before opting for the “run until you’re not dead” tactic instead, not looking at my watch anymore and running the last kilometre as fast as I could with every ounce of energy that I had left.

After what seemed like the longest four minutes of my life, my Garmin watch finally confirmed that I had done it with 12 seconds to spare. I did a celebratory hurl of vomit over the fence, and a soldier came over to me with post-run snacks as I lay in the puddle… I had finally done it; at the tenth time of asking, I had run a 10k in 40 minutes, achieving a personal fitness milestone, feeling proud and happy about my determination and falling hopelessly in love with running all over again.

Conclusion: Running 10k in 40 Minutes Requires Planning & Structure

Unless you have youth on your side or are an experienced and talented distance runner, pushing for a sub-40 10k will take some planning and preparation and even being open to trial and error. My training plan isn’t too different from my plan to run 5k in under 19 minutes, although it differed with mileage and intensity.

  • Increase your mileage. Going from an all-out 5k effort to a 10k all-out effort is way more than double. It is double on paper, but trust me, keeping up the pace at 5 more kilometres is intense, and to get your body ready for that – you have to up your weekly mileage considerably. 
  • Zone 2 For The Win. Slow, conversational-pace runs have been the cornerstone of my training since taking running seriously. If it’s good enough for the elite runners that we had the privilege of witnessing in the Paris Olympics, then it’s good enough for us plebs. Believe the hype—Zone 2 runs work!
  • Weekly long run. Run once a week at a distance greater than your weekly Zone 2’s. I did 15k on most Sundays, nice and slow.
  • Interval Training. Take 15 seconds off the time (so faster) you want to run your race pace per kilometre. Aim to run for 400 metres, then jog for 2 minutes for recovery. Repeat 5 times. Don’t worry; you won’t get it the first time, but you will get there over the weeks if you stay consistent. Once you’ve nailed down that time x5, opt for x6, then x7 then x8. You will build up so much confidence in your pacing ability.
  • Strength Train. It doesn’t matter if you are training for a 5k Parkrun, a 10k trail run or planning to run 100 miles; LIFT WEIGHTS (yes, that includes bodyweight exercises). It won’t hinder you if you structure it correctly; it will do the opposite, and your running will improve thanks to your stronger body. It doesn’t have to be boring either – I have a preference for gymnastic rings and dumbbells. Find out what works best for you which will be much more sustainable. And ladies, you will not look like Arnold Schwarzenegger in Predator if you strength train alongside your running. You will simply look even more lovely than you already look.
  • Trial and Error. If your training is becoming detrimental to your running, you may be overtraining or under-rested. Swap one or two intense weekly exercises for active recovery, such as a slow run, cycling, yoga, or a mobility workout.
  • Get your mind right. If your mind is chaotic and you’re drowning in negativity daily, it will be hard to “see” yourself as a sub-40 10k runner. I had a lot of stress on my plate, and taking an extended break from alcohol with meditation and journaling created space in my mind, which gave me more energy during my runs. I would have dismissed this sort of chat as woo-woo bullshit a few years ago, but I believe it now. The mind is a potent tool, and we must be careful how we use it and not take it too seriously when it’s being whiny and cruel. So look after your head as much as your body in training; they will work in semblance to you and your quest for a faster run.

Thanks for reading, folks. I am chuffed to bits to be in the sub-40 10k club. It may have taken a few cracks of the whip, and my initial approach was a little unorthodox, but I got there in the end. I’m enjoying my fitness journey and have fallen back in love with running.

I hope I inspire others to do something similar.

My tips and sentiments above will help you regardless of your running time goal at whatever distance. Feel free to sign up for my newsletter and my socials to keep up to date with travel and fitness updates; my next challenge is to run a 15k in 1 hour before the end of the year.

Start that clock!

Anthony Middleton

A former loser who took a risk. I now live in Chiang Mai, Thailand and after visiting over 100 countries I plan to see all of them. My current fitness challenge vs the clock is to run a half marathon in in one hour, 30 minutes before September 30th.
Ultra runner walking in desert

Hi, I'm Anthony!

In November of 2010, I took on a mammoth challenge against the clock in a quest to upgrade my miserable life. I went out of my comfort zone and turned it all around. Ten years later, I’m completely location independent…

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