Doubles: Why and How I Run Twice-a-Day

Why on earth would I want to run twice a day when I can just run once a day?

This must have been what I thought when I first read about running twice-a-day (also known as running a “double” or “doubling”).  But, I learned to appreciate them during the marathon training cycles when I followed the Pfitzinger’s Advanced Marathoning plan that maxes out at 85 miles a week.  Here are my thoughts on doubling – what I’ve read about them, why I do them, and how I integrate them into my training schedule.  However, for further reading by actual experts, I’ve included a list of helpful articles on doubling at the bottom of this post.

The Basics

When it comes to doubling, Why? is an obvious and reasonable question.  Here are some reasons why a runner might want to run twice-a-day:

  • Building mileage.  For marathoners, this is a very compelling argument for doubling since most training plans have them running upwards of 50 miles a week.  Running twice-a-day enables runners to achieve mileage goals by adding additional runs to their schedule.
  • Stress management.  Breaking a single run into two runs can be easier on the body.  For example, doing 6 easy miles in the morning followed by 4 easy miles in the afternoon after a full recovery is potentially less stressful on the body than running 10 easy miles straight.
  • Scheduling.  Not everyone has time in their schedule for longer workouts – particularly during the work week.  Using the 10 easy mile example, they might be able to run 6 miles in the morning and then another 4 miles during their lunch break or after work though.

But, there are also some good arguments against doubling, including:

  • Singles are enough.  Are runners who are doubling maximizing what they’re getting out of single runs?  Guidance varies but some argue that unless a runner is doing upwards of around 75 miles per week, they should probably stick to singles.
  • The “training effect”.  Is running a double as effective as running a single?  Again, using the 10 miler example, running 10 easy miles continuously probably has a different training effect than running 6 easy miles, taking an extensive break, and then running another 4 easy miles.  Some runners might be increasing their mileage by doubling at the expense of building their endurance.

I see the wisdom in these arguments against doubling and yet I work them into my training anyway.  I think I race better when I’m running 70-80 miles a week and I find I can only maintain that mileage while minimizing stress on my body if I make some of those miles short, easy runs.

The Workout

Convinced?  Well, before lacing up for the second time today, here are some suggestions on how to work doubles into your schedule.

  • Don’t make your long run a double.  Dividing the long run into two short runs defeats the purpose of that workout.  In order to build endurance, the long run should be one continuous run.
  • Give yourself time to recover between workouts.  If you’re not fully recovered, you risk over-stressing your body.  And, you might as well have run a single.  Advice varies on the exact amount of time between workouts but 4 hours seems to be a common recommendation.
  • Eat something between the two runs.  Replenishing some of carbohydrate and water used during the first workout is a good idea.  I usually eat something light like a bagel and some sports drink, and then have a hearty meal after the second run.


Depending on when I’m doubling, some of my post-workout concerns are the same that I have when run commuting.  For example, since I usually double during my lunch break, my biggest problems tend to be dealing with other employees using the shower facility, and finding something quick but nutritious to eat.  If I run commute home as my double, I take home all of the items I’ll need that evening and my normal commute the next morning – my house key, Metro card, identification, my ATM card, and some cash.


Laundry.  This may seem like a trivial concern but doubling adds another outfit to the high mileage runner’s mountainous laundry pile.  I solve this problem by having more running clothes than any sensible person should own.  However, a less costly solution is to double up on wearing some items by air drying them on a laundry rack.

Additional Resources

Here are some useful articles by actual experts on doubles.

Jeff Gaudette, “Doubles: The When, Why, and How to Run Twice a Day“, RunnersConnect.

Steve Magness, “Strategies for Doubling“, Runner’s World.

Lisa Marshall, “Pros and Cons of Running Twice a Day“, Runner’s World.

Pete Pfitzinger, “Should You Run Two-a-Days?“, Runner’s World.

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