My Age Adjusted Half Marathon Times

After reading Runner’s World Train Smart Run Forever by Bill Pierce and Scott Murr (see my review here), I wanted to see how my age adjusted half marathon times looked. One of the main takeaways from the book is that although your race times will inevitably increase as you get older, particularly beginning in your 40’s, your age adjusted times should actually remain the same or decrease if you’re lucky.

Warning: this blog post is full of data and probably only for true data geeks. If it puts you to sleep, don’t say I didn’t warn you. For those of you that are into this kind of thing, you’re in for a treat!

First I plotted all of my half marathons from the very first one in North Carolina to the  one I ran in Utah. I did not include my last race in New Jersey, however. This includes half marathons I ran over an almost 20 year span with 41 half marathons in 39 states, so there are a lot of variables here besides just age to consider. For instance, the terrain and weather varied greatly from one race to the next. Beyond that, I was anemic for a period of years, so there is a spike in my times due to that until I was fully recovered.

You’ll see my race times are in red and my age adjusted times are in black. Initially, the age adjusted times are the exact same as the race times, so you’ll only see a black square for the first few races. Only around my mid-30’s do you even start to see a separation between the red circles and black squares.

Screen Shot 2017-04-25 at 2.36.43 PM

There is also a spike in my times for the race in Colorado. Running at a high elevation really took it out of me so this was definitely one of my slowest finish times. I decided to take out the times when I was anemic and the points from Colorado, since I thought they were outliers from the rest of the data.

Screen Shot 2017-04-25 at 2.42.02 PM

OK. So now I’ve removed the points from when I was anemic and my race in Colorado. With these two graphs, I can get a better idea of the “big picture” of my running.  The obvious outlier in the first one is my first race ever. Even with that point included, however, the general trend for my age adjusted times are decreasing, as shown by the linear fit shown by the blue line. When I throw out my first race time, the trends are more consistent. My race times have averaged around 2 hours and a couple of minutes over the years and have slightly increased. However, and here is the main point of the whole thing, my age adjusted times, again, as shown by the blue line, have definitely decreased over time, which is what I wanted to see.

Another interesting thing is the very large degree of separation between my race times and age adjusted times in my 40’s. For my half marathon in Utah, the difference between these two times is almost 10 minutes!

My plots aren’t anywhere near as “pretty” as the ones in the book, but I think maybe a big reason for that is the author’s age spans over a much longer time than mine do. Perhaps when I’m in my 70’s (as one of the authors is) and I plot my race times versus my age adjusted times, I’ll see something even more linear, rather than what I see. Hopefully even though my race times will (inevitably) increase, my age adjusted times will continue to decrease linearly.

Here’s the link to the Runner’s World website where you can plug in your numbers to see your age-graded race times.

Author: runningtotravel

I'm a long distance runner with a goal of running a half marathon in all 50 states in the US. I also love to travel so I travel to other places when I'm not running races. Half the fun is planning where I'm going to go next!

15 thoughts on “My Age Adjusted Half Marathon Times”

  1. I LOVE DATA!!!!!! Great post! I love geeking out over numbers and posts like these make me so happy to read. You’ve been running for a long time. I’ve only been racing for about 5 years, so I don’t have as much data as you.

    Liked by 2 people

    1. I’m glad someone other than me enjoyed this. This is the first time I’ve ever analyzed all of my race data. It was definitely interesting for me, and I was happy to see it going in the trend I wanted it to.


  2. This is awesome!! Love the data crunching…this blows my monthly dorky data out of the window!! Great job…I have seen this calculator before but have not spent too much time with it. After reading your article I plugged in a few recent sample race times and, at a very high level, noticed a similar differential between actual race time and age adjusted. But, my running history is much shorter given I only started when I was 42-43, which in turn changes the pattern because I was much slower when I was newer to distance running, so I’ve actually got faster with age but hit a plateau last year – but I also ran 6 full marathons last year which changes the equation too. I noticed a roughly 10 minute differential at the half-marathon and 18-20 minutes at the marathon distance at ages 46-48. Great post…I’m going to have to play with this some more!

    Liked by 1 person

    1. Thanks, James. I’m gold you enjoyed it! I know you do like data crunching so this seems like something you would enjoy! Having a longer racing history helps to make the data look prettier when it’s presented but you can still get a feel for the trend for you. It sounds like your trend is going in the right direction when you plug in your race times. Have fun playing with it!


  3. I have never entered a race. And posting my best 5k running time in that calculator, I can see I probably shouldn’t waste my time. I’d have to shave off 11 minutes from my best time just to be competitive with 70-year-olds! I just turned 60. That’s depressing.. 😦


    1. I’d look at it like this- since it will be your first race, it will be a PR (personal record) for you, which is always a good thing. Plus, your race times are likely to improve after you’ve done a few. Most people’s race times are faster than their normal running times because of adrenaline and competitiveness. You should try one and see how you like it!


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