Running a 50-miler: Pacing



The weekly cumulative mileage goals to build to a 50-mile run over a 24-week period are noted below. We are in the 12th week. All but a very few of the 150 runs have but one purpose: to build our aerobic engine. Back in the day, we called this “LSD” – no, not the drug – Long Slow Distance.

Basically, our bodies adapts to training at a low exertion level by creating a strong aerobic engine. We burn very few “extra” calories (above the normal daily burn rate of between 1,200-2,000 calories, depending on your age, weight, etc.) without exercise. We burn mainly fat at low efforts of exercise, stored carbohydrates at medium efforts, and protein in the form of muscle breakdown at extreme effort.

Besides becoming leaner, long, low efforts of exercise allow our bodies to build a better oxygen delivery system to our muscles, while also providing a better flushing system for the buildup of lactic acid. The result is that we are able to go faster, go longer, or do both over time with the same perceived effort. In other words, done properly, 10 miles today will feel like 5 miles felt week before.

So, what pace should you run? This can be a complicated answer. You could have your lactic acid buildup tested. You could measure your heart rate a different levels of perceived and actual efforts, etc. Here is the easiest way to determine your what is low, medium, and extreme effort:

  • Low effort – you can pretty easily maintain a conversation while you run
  • Medium effort – heavy breathing makes it difficult to maintain a conversation
  • Extreme effort – talking is out of the question; you are giving it all you got

You should run about 80% in the “low effort” zone, and 10% in the other two zones, if you are looking to lean up and build a more robust and efficient aerobic engine. If you train this way, with also increasing the load by upping distances, long runs will become more and more manageable.

As always, send any questions or comments to mail

Weekly Mileage for 24-week, 50-mile Race Goal

Week 1 – 10 miles                Week 9 – 35 miles                Week 17 – 45 miles

Week 2 – 15 miles                Week 10 – 15 miles              Week 18 – 55 miles

Week 3 – 20 miles                Week 11 – 25 miles              Week 19 – 65 miles

Week 4 – 15 miles                Week 12 – 35 miles              Week 20 – 75 miles

Week 5 – 20 miles                Week 13 – 45 miles              Week 21 – 45 miles

Week 6 – 30 miles                Week 14 – 55 miles              Week 22 – 35 miles

Week 7 – 20 miles                Week 15 – 40 miles              Week 23 – 10 miles

Week 8 – 25 miles                Week 16 – 25 miles              Week 24 – Goal Run