For years, I've always played around doing fartlek training and never pushed myself to run fast (7-min/miles is fast for me) for more than one mile.

Today, I decided to run 7-min/miles for as long as possible. At mile 1.8, I felt good but my quads completely shut down. I had to start walking. To my absolute shock, after about 1-minute I was able start running again (but a much slower 10-min/mile pace which I can run at for several miles with no problems).

Can you really clear enough lactic acid in just 1-minutes out of quadriceps to go from just being able to walk to being able to run again? That does surprise me. Or, maybe something else is happening to make my quads tap-out. The issue is simply my quads are not strong enough to support my body weight which builds up the lactic acid, right? My quads don't "hurt", somehow I just know/sense they cannot absorb any more impact.

2 Answers 2


The answer is "sure".

You have a given capacity - based on training - to buffer lactic acid out of your system. To do so requires oxygen.

If you are running at a rate that generates lactic acid faster than you can buffer it out, you will accumulate it, and after a while, you'll have to slow down. When your aerobic system cleans up enough of the lactic acid, you'll be able to exercise again.

  • I suppose that would imply that one would recover faster by jogging than walking, since one is breathing more readily in the former case (i.e. jogging)? Commented Jun 9, 2014 at 18:45

Keep in mind lactic acid generation itself is actually a good thing - it's just directly correlated with other fatiguing mechanisms. Lactic acid (via the "lactate shuttle") allows for eventual further extraction of ATP via aerobic mechanisms.

When you do hard cardio, you generate ATP anaerobically, which produces lactate as by product of breaking down glycogen anaerobically. That lactate actually still hold energy potential, but your body has to get good at using it.

In other words, a large of getting in better cardiovascular "shape" is improving your body's ability to breakdown lactate aerobically into ATP.

All that aside, there are diagrams out there that illustrate the rate of lactate removal as a function of exercise intensity over time. The "optimal" recovery intensity is about 40% of your VO2max.

Walking would be below 40% of your max, but still aid in removal vs. just standing.

Feeling better in 1 minute is definitely possible as long as your lactate build up is not very large (i.e. near VO2max efforts).

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