You might (or you might not!) wake up during a particularly pointless conference call with the bright idea of running a 150-mile ultramarathon in the Sahara Desert. Unfortunately, accomplishing such a feat is a galaxy away considering your current fitness. The idea of a finisher's medal around your neck is ridiculous. That's why it is a 'dream' not a 'plan'.

The gulf between where we are now and where we dream of is often too wide to leap in one bound. Because there are no stepping stones the crossing can look impossible.

But you remember that you once bought a pair of expensive trainers in a hot-headed and short-lived New Year's Resolution to get fit. Back home that evening you eventually find the trainers, unworn, under a pile of doughnut boxes.

Out of curiosity, you tug on the snazzy yellow shoes. You tie the laces snugly and bob up and down tentatively in the living room, flexing your knees and wiggling your toes.

You step out outside, lock the front door, hide the key under a plant pot and check nobody is watching. Then you sprint off down the street.

By the time you reach the corner, however, you grind to a gasping halt, bent double and retching beneath the streetlamp. What were you thinking? What sort of a daydream was this? How could you have even considered that this was preferable to the blissful ennui of a meeting with far too many attendees and a plate of chocolate biscuits?

You turn around and stumble slowly home with a look of bewildered astonishment on your face. You switch on the TV and your heart rate eventually settles to a safe level. That marks the end of your good intentions. 

But imagine if after the ignominy of Day 1, you wake up on Day 2 and decide to give it another try. You remember that you are middle-aged these days and no longer the King of the Playground. You leave your front door at a more realistic pace.

This time you manage two minutes of running before you capitulate. Encouraged, on the third day you run for three minutes. After a week you can run for seven whole minutes.

You run to the café to bask in your achievement. Your friends laugh at your sweaty enthusiasm.

'Seven minutes?' they scoff. 'That ultramarathon's going to be a piece of cake, mate. Here, have a piece of cake instead.'

And yet, despite their mocking, you persevere, adding a minute to your run time every day. After a month of effort – a substantial 1/12th of a year – you can still only wheeze your way through 30 measly minutes of jogging. 

'Surely I should be fitter than this by now?' you wonder in despair. Your thumb twitches towards the doughnut delivery hotline number on your phone. 

This is a familiar hurdle on big projects. You launch with great fanfare and enthusiasm. But, after an initial flurry, progress is paltry. Success is still so far away. The temptation to quit returns. 

This is where you need to be stubborn and remember only today's Doorstep Mile: get out the door and start running. It is better to measure your trajectory than your current ability. Because if you keep going, if you stubbornly add 30 minutes a month, by the end of the year you will run for 365 minutes. That's a six-hour monster run. You could complete any ultramarathon on the planet with endurance like that!

This is the power of accumulating small steps and heeding only the next daily Doorstep Mile. 

OVER TO YOU:
What can you begin today and then improve by one minute or 1% tomorrow?