Lactic acid gets a pretty bad rap and although this is understandable there are a few things we need to clarify about this stuff. Lactic acid does cause a temporary burning sensation but it isn’t the main cause of your achy muscles the day after a particularly hard workout. Delayed onset muscle soreness (or DOMA) is likely the culprit of that pain.
As you first start running, or tackle a new and more difficult distance you may deal with more lactic acid. This will likely decrease over time and with proper training. It is most important to learn that this stuff isn’t really the bad guy and actually helps you as a runner and endurance athlete. It doesn’t stunt growth and in reality helps to build muscle over time.
Lactic acid is used by the body when breaking down carbohydrates for energy. In fact, it really is used as fuel. However as your training duration and/or intensity increases the lactic acid begins to increase in production and your body cannot remove it at the same pace. This is where lactate buildup comes into play.
As the formation of lactic acid builds up with increased intensity or duration there are ways to teach your body how to increase its ability to both deal with and remove it more quickly. To increase your capacity to handle lactic acid and remove it faster you need to increase your level of intensity or duration. Doing activities with a lot of lactic acid in your system helps your body to produce an enzyme that uses the compound as fuel. The good news is, there are several different kinds of workouts that will help your body reap the benefits of lactate removal.
Over distance training helps your body make cellular adaptations that speed up the lactate removal. This is where your long slow distance (LSD) runs come into play. These runs are awesome because they don’t require you to run at a hard intensity but instead to go out the door and run at a nice easy, conversation pace. Long distance runs are typically a minimum of an hour and a half in duration and can last upwards of four or more hours if you are marathon or ultra training. These runs require you to be patient and take your time. Being on your feet for this long does make cellular changes that allow your body to utilize both oxygen and lactic acid more efficiently.
On the flip side, as your run faster lactic acid builds up and is removed faster with proper training. Working your body in this way can help teach it to remove lactic acid more quickly and in return improve your overall running. Tempo and speed workouts as well as adding strides once a week to the end of a workout teaches the body to open the flood gates of lactic acid and then work to remove it. Personally, this isn’t my favorite workout but I do these because I know they offer the best benefits.
To be fair, stop blaming lactic acid on your achy legs. Be your own best running friend and start adding in a weekly tempo or speed sessions and you will soon start to find your body not only running faster but more efficiently. You will notice that your endurance will begin to improve both on a cardiovascular and muscular level.