The Human Odometer. How Far Can We Run?
With a good wind, the best of health, and an immortal mindset how far could someone run in a lifetime?
TLDR: 2,384,112 km (1,481,419 miles).
That’s 90 times around the world.
Here are my workings:
This basic equation is simple, yet those two factors represent multiple variables that cut into life, possibility, and sheer opportunity cost.
Days Able to Run
Taking a generous lifespan of 81 years there are 29,565 days in a lifetime. Even the best among us will concede it is not possible to run every day.
Take this age-graded PEF (Peak Expiratory Flow) chart. It show’s your expected lung capacity by age:
It suggests that even in laboratory conditions there will be times at the start and end of life when it’s not possible to run. Combining this with an expectation of education and we can discount the first 16 years, leaving 23,725 days.
There is running, for sure, my five-year-old does a magic 2km, but it’s one to add or discount separately.
Injury and recovery cut into this total. Because this is a maxim I am assuming peak possible health. While novices carry higher injury rates, a Dutch study found that even experienced runners received an average of 4.11 injuries per 1000 hours.
The good news is that ultra-marathoners get off lightly in the injury room — the American College of Sports Medicine found 95% of injuries were minor in nature and mostly due to skin-related disorders (74.3%).
On the flip side, some less obvious injuries do relate specifically to ultra-distance. A 50% increase in allergies and asthma — put down to time spent outdoors, as well as an increase in stress fractures. A BMJ study also points to potentially long-term cardio risks.
There is a high inherited aspect to these factors, I have never broken a bone but am almost certainly devoid of the AGTR2 gene that favours slow twitch muscle fibres. For a maxim, I’m assuming individuals with the greatest of luck in the lottery of life.
It’s also worth noting these studies reference extremes and should in no way give you hesitation hitting the pavement yourself — the pros outweigh the cons.
Even taking a best-case scenario, the greatest athlete running continuously can chalk off an average of 2 days per month for injury. These days will have a higher instance in the earlier and twilight years of the runner’s lifetime.
This leaves 22,165 days.
As a caveat, there are courageous tales of people running hundreds of days of consecutive marathons — Ben Smith’s 401 in 401 days comes to mind, but for a maxim, we have to assume greater mileage than 26.2 miles a day.
Finally, there should be some consideration that runners take rest days, even at the peak of their careers.
Paula Radcliff, the fastest female marathoner of her generation, took one day a week. As a maxim, let’s quarter that, discounting one day every month.
Leaving 21,436 days of active running.
Max Distance Per Day
As alluded to earlier, not all times in life are born equal, a 30-year-old can cover more mileage than a 16-year-old and both can outrun an 80-year-old.
To devise our potential chart we need to plot the points, where does it start and where does it end?
The record distance over 24 hours currently stands at 319.614 kilometres (198.6 miles) by Aleksandr Sorokin in 2022, a feat made all the more remarkable by the fact he was 41 at the time.
A more reliable number for repetitive daily mileage comes from New York’s Self-Transcendence 3100 Mile Race, a mind-numbing 5,649 laps of a single extended city block. Runner’s World places it as the longest certified foot race in the world.
The record holder, Ashprihanal Aalto, managed to complete it in just over 40 days, averaging 123.517 km (76.75 miles) per day. Interestingly, he too was in his 40s (44).
Although there is no guarantee he could consistently maintain that pace beyond 40 days — by accounting for limited injury and rest days in the above we can take 123 km per day as our high bar.
To extrapolate this into lifetime running, I’m using a large field study from the Berlin Marathon:
This marathon is famous for its flat, optimal conditions. The last eight progressions in the marathon world record have been on this course.
While this specific sample is not indicative of exclusively world-class athletes, it does give a good indication of the kind of decline you could expect with age. Bear in mind the older runners here will be from a significantly diminished pool, representing a field closer to optimal performance.
An interesting bit of takehome is that over a lifetime it appears women maintain closer to their peak for longer.
The examples I’ve used to develop my formula have come from male athletes, however, there is good evidence to suggest that the difference in gender whittles away at the top end of endurance.
Plotting 123 km as our 100% we can develop this chart:
Levelling this out, accounting for the 80% weighting on <20 and the 40% weighting of 80–84, we get to an average mileage of…
111.22 km per day (69.11 miles per day).
706km per week*
3057 km per month*
Adjusted for days unable to run
The Total
This gives us our overall result of 2,384,112 km (1,481,419 miles).
At the absolute peak, it is possible to run to the moon and back.
It’s potentially possible to do it three times.
Looking at running from this abstract perspective makes you wonder what new limits and races we could expect.
The WRA (World Runners Association) states a foot race around the world must consist of at least 26,406 km (16,300 miles). This should be hypothetically achievable in 8 and a half months.
There may well be an official race around the world at some point. A start date of January 1st and a cut-off of point of one year seems logical. It might even be the first race you can only run once.
Learning from the Self-Transcendence Marathon you could expect many runners to not complete it — but even in the attempt, incredible feats would be made.
Postscript: Who’s counting?
Whether a million miles is possible is only ever hypothetical — journaling every day in life is not currently achievable or indeed remotely desired, making it impossible to validate.
The mechanics of this also seems to detract from something the longest-distance runners appear to hold as a common epithet; that distance is but a number.
If You Want To Run, Run A Mile. If You Want To Experience A Different Life, Run A Marathon. If You Want To Talk To God, Run An Ultra.” — Dean Karnazes
Make this better
If you can think of errors or an improvement to the formula used let me know in the comments and I’ll amend as appropriate. 🙏
