Lactic acid is kind of like your best friend and worst enemy. It’s your best friend in that it’s the byproduct of what ultimately allows you do higher intensity work and grind through some challenging workouts. But it also your enemy since it also plays a central role in regards to the resulting muscle soreness we can feel thereafter (well, technically it’s the accumulation of hydrogen ions attached to pyruvate, which then forms lactic acid, but for the sake of this article, we’ll just say it’s the lactic acid itself).

There are a number of different ways to help clear out lactic acid from the body after a workout, but the absolute best way is to perform a “flush” right after you finish your high-intensity workout. A proper flush can greatly reduce the amount of lactic acid that winds up sitting within your muscles after your workout session, which will then greatly reduce soreness thereafter.

If you’re looking for how to speed up muscle recovery from exercise so that you can get more training sessions in each week (and higher quality ones too), then this blog post is for you.

This article is going to cover the basics on what lactic acid/lactate is, how and why it accumulates and of course, what you can do to get rid of as much of it as quickly as possible following your workout. The more effectively you get rid of this stuff after each challenging workout or activity session, the less sore you’ll be thereafter and the quicker you can then dive back into your next workout or activity session.

FYI: The term “lactic acid” and “lactate” are often used interchangeably, so for the purposes of this article, consider them to be one in the same.

Article contents (Quick links)

*Click any of the bulleted headings below to instantly jump to that particular section*

• What is lactate/lactic acid?
• How, why and when does it accumulate within the body?
• How the lactic acid flush moves lactic acid out of the muscles
• How to perform a lactic acid flush in order to recover much quicker
• The three keys to performing an effective lactic acid flush
• Concluding remarks

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What is lactate/lactic acid?

I won’t get into all the geeky, scientific exercise physiology, but I believe that you will benefit from having a very basic understanding of this substance as this knowledge can help you better understand what’s happening in the body when it builds up. As well, knowing why it builds up and thus knowing when to expect it can help you fight it off much more effectively. If you aren’t interested in becoming as informed as possible, just skip to the “How to perform a lactic acid flush in order to recover much quicker” section.

A brief overview of lactic acid: In short, lactic acid/lactate is a metabolic byproduct that your body produces in exchange for providing energy to your muscles when performing short-term, high-intensity exercise or movement. Lactic acid/lactate is always being built up within the body to rather low extents throughout regular, daily activity, however, since these regular, daily activities are of very low intensity, the body produces hardly any of it, and what it does produce is broken down at a much greater rate than to which it accumulates.

The result is that we don’t experience muscle soreness with our regular, daily activities since most regular, daily activities are very low intensity.

How, why and when does it accumulate within the body?

While our bodies don’t produce much lactate with low intensity demands, the situation quickly changes once we move towards more high-intensity demands. The muscle cells within our body need energy to produce movement (such as during exercise or working out). Their preferred way of getting this energy is through using oxygen in a metabolic process known as the Citric Acid Cycle (also known as the Kreb’s cycle or TCA cycle) (link takes you to Wikipedia page). This particular metabolic pathway is known as an aerobic pathway since it requires oxygen to operate.

Unfortunately, it takes a bit of time for our cells to produce the energy they gain from using this metabolic pathway. This typically isn’t a problem so long as exercise is performed at an intensity that does not demand energy from the aerobic pathway at a rate quicker than what it can produce.

When the aerobic pathway can’t provide energy quickly enough

When exercise intensity becomes high enough, our body’s cells (such as muscle cells working to perform the exercise) can’t get the energy they require quickly enough from the aerobic pathway. This is the energy needed in order to keep the exercise going. As a necessary result, the body switches to a different metabolic pathway (one that doesn’t require oxygen) in order to keep energy flowing to the cells. This is known as the anaerobic pathway (it is also called the glycolytic pathway).

This particular pathway is pretty neat in that it allows the body to undergo sustained higher intensity output for a short period of time without the use of oxygen (upwards of around two minutes), but it comes with a cost: a build up of metabolic byproducts (“junk”) that build up in the muscles and the blood stream. That “junk” is of course lactic acid.

Think of this system like a jet engine: it can produce a lot of power, but as the engine works it leaves behind a trail of undesirable chemicals throughout the air as the result. In the case of the body, the trail of undesirable chemicals left behind is lactate that sits in the working muscles.

As the anaerobic pathway first kicks off, the body is able to buffer one of the main byproducts derived from this pathway: hydrogen ions. So long as the body “soaks up” these excess ions, exercise can continue. The body does exactly this by taking a substance known as pyruvate and sticking two hydrogen ions to each pyruvate molecule. Once this has occurred, the substance is known as lactic acid.

As high intensity activity continues to go on, the rate of lactate build up within the body exceeds the rate at which it can be broken down (lactate is broken down in a process known as the Cori cycle, which takes place within the liver, where lactate is broken back down into glucose).

How the lactic acid flush moves lactic acid out of the muscles

Once a high volume of high intensity exercise has been performed, there is a lot of lactate that floats around the body’s blood stream and within the muscles themselves. The body will ultimately clear all of this out and break it down on its own, but at a very slow rate, which ultimately means you could be sore for a few days. We can greatly expedite this process if we take advantages of a few key physiological principles.

The first key principle is the continuous, cyclical nature of contraction and relaxation of muscles as blood flows through them. This creates the phenomenon of the skeletal muscle pump. The second principle we take advantage of is the elevated heart rate and resultant increase in blood flow rate throughout the body.

The flush therefore works by keeping blood moving throughout the entire body (since the heart rate is staying elevated) while the movement you’re producing forces the working muscles to contract and relax repeatedly.
As the blood flows into the muscles, the muscular contractions mechanically pump or “squeeze” the blood along, with the result being a facilitated removal of lactate (from the muscles) back to the liver so that it can be broken back down into glucose (in a process known as gluconeogenesis).

The key here to note, however, is that the heart rate needs to be continuously elevated to a certain extent in order to really drive blood throughout the entire body as much as possible. Sorry everyone, you can’t just do more bicep curls and call it a “flush”.

So now that you know the general principle behind how a lactate flush actually removes lactate from the muscles, let’s look at the ideal parameters that go into performing an effective flush.

How to perform a lactic acid flush in order to recover much quicker

So now that we’ve gone through exercise physiology 101, let’s next look at how you can go about effectively clearing this junk out of your muscles and circulatory system as quickly as possible. After all, clearing out lactate from your muscles after your exercise session will reduce muscle soreness and thus help you to get your next session in much sooner!

There are a few key principles that must be followed if you want to get the most out of your lactate flush.

Three three keys to performing an effective lactic acid flush:

1. Performing it immediately after your exercise session
2. Performing it at the right intensity (determined by heart rate)
3. Performing it for the right duration of time

Performing the lactic acid flush immediately after your exercise session

If you’re going to want to get the most lactate out of your muscles as possible, the flush needs to be done immediately after you finish your workout or exercise session. This means ideally within approximately the first ten or fifteen minutes. This is largely since you want to keep your body’s elevated blood flow state (from your exercising) occurring throughout your entire body.

If you let your heart rate drop too much, the heightened blood flow state your muscles are experiencing from your workout begins to diminish and more chance for lactate to stagnate within the muscles. This results in less lactate being cleared when trying to flush it out.

In other words: keep your heart rate up and more blood will be flowing to the muscles in order to clear out the junk before it has a chance to settle in.

Performing the lactic acid flush at the right intensity

To perform an optimal flush, you’ll want to pick a piece of aerobic exercise equipment that will allow you to perform continuous movement at approximately 60-65% of your maximal heart rate. My preferred piece of equipment for this has always been the stationary bicycle as it seems to be the most convenient in a lot of ways. You can try other pieces of aerobic equipment if you’d like, but I’d personally recommend a bike.

Regardless, you’ll likely need a bit of resistance to the pedals to achieve spinning at 60-65% maximal heart rate while keeping the legs moving at an RPM between 90 – 100.

By keeping the largest muscles within the body (muscles within the legs) continually contracting and relaxing, we’re capitalizing on the use of the skeletal muscle pump. This continual pumping action forces small veins and arteries to repeatedly squeeze and relax in a way that helps keep pushing blood (carrying the lactic acid) along throughout the body and back towards the liver.

Performing the lactic acid flush for the right duration of time

To get the most out of your flush, you’re going to need to hold the aforementioned steady-state intensity for approximately fifteen to twenty minutes. This is a long enough period of time to ensure that there has been enough elevated blood flow through the muscles but not so long as to produce unnecessary amounts of muscular or physical fatigue.

If you’re pressed for time, you could even do less time than this, as something is almost certainly better than nothing, however just keep in mind that if you only go for say, ten minutes, you may not get as much lactate flushed out of your system as possible.

Concluding remarks

Pushing the body during high-intensity workouts or activities is a good thing for us in many ways, but it can leave us prone to excessive amounts of muscle soreness for a short period of time thereafter. While soreness can be due to different physiological factors, one such attributable factor tends to be the extensive build up of hydrogen ions that ultimately become attached to pyruvate, forming lactic acid.

This built up accumulation of lactate (or lactic acid) that resides within muscles after a workout or exercise session can be an issue since it may require us to take a longer than ideal break before we can partake in our next exercise or activity session due to the muscle soreness it is believed to generate.

The goal of the lactate flush is to ensure that the high volume of hydrogen ions (which attach to pyruvate to form lactic acid) get pumped or flushed out of the muscles and into the bloodstream as much as possible until they ultimately arrive at the liver, at which point it will be broken back down into glucose. To do an effective flush of lactate, you’ll need to do a continuous, aerobic movement (riding a bike is the most ideal) right after your workout, at an intensity of approximately 60-65% of your maximal heart rate for about twenty minutes.

The end result of an effective lactate flush is much less muscle soreness and/or stiffness that is felt within the next 24 – 72 hours and your ability to then get back in the gym much sooner and do it all over again!

Have fun!

-Jim