Does Lactic Acid Really Cause Sore Muscles? Here’s What You Need to Know

Nobody likes being sore. Read on to learn why it happens.

By: Natalie Bohin

Let’s talk lactic acid for a minute. It’s something we all blame for those muscle cramps and charlie horses many of us experience after an intense workout. You wrap up a power pump only to feel exhausted and pain every time you go to sit down and stand up. Sound familiar?

Yeah, you probably think it’s good old lactic acid, but here’s the thing. Lactic acid is one of the most commonly misunderstood responses in the body. It’s often blamed for the ‘burn’ you feel after an exhaustive workout. You may think of lactic acid as your workout’s worst enemy and the reason behind your aching muscles. But, what if there was more to the story?

What is Lactic Acid?

First, to better understand what’s really causing those sore muscles, we need to look at what lactic acid is. First, let’s get real about what lactic acid is and what it isn’t.

You’ve probably at some point, or another heard ‘lactic acid’ and ‘lactate’ thrown about by coaches, trainers and other sports experts, that assume that they are the same thing. But, technically they are completely different. Lactate is produced by your body in response to a workout like a strength workout with FitOn trainer Katie Dunlop and serves as fuel for your muscles and delays fatigue.

Lactic acid, on the other hand, isn’t formed in muscle or produced by the body at all during exercise. Guess what? Lactic acid actually doesn’t have anything to do with muscle soreness after a workout, so while you may have been blaming lactic acid your whole life, the truth is that an increase in lactic acid doesn’t make your muscles sore.

So what actually makes you sore after a grueling workout? In order to understand how this works, you need to understand the way your body fuels your workout.

What Happens to Your Body When You Start Exercising?

During intense exercise, your body needs energy to fuel your workout. To do this, it breaks down glycogen, carbs and other molecules to produce ATP, or adenosine triphosphate. ATP is then broken down releasing energy, including hydrogen, throughout your muscles.

Those hydrogen ions then start to build up in your body, causing a drop in your body’s PH levels and interfering with your muscle’s ability to contract.

Your body’s PH levels are actually what leads to a mid-workout burn that will no doubt cut your workout short. This entire process of creating energy requires oxygen and some exercises are so intense that your body can’t use oxygen fast enough to produce fuel.

When you don’t have enough oxygen to perform this process, your body produces lactate to fuel your muscles. The lactate isn’t actually hurting your muscles though. It’s trying to help your muscles from giving out on you.

Your muscles become acidic when they don’t get enough oxygen and their PH levels drop. As you lose energy and power, lactate swoops in to save the day, acting as a protective mechanism.

The Bottom Line

Despite being on the hook for muscle soreness for decades, that sore feeling you get after exercise isn’t actually caused by lactic acid. Post-exercise soreness is simply a result of mechanical damage to muscle fibers and inflammation.

Surprisingly enough you need lactate! Lactate is essential to the exercising process. It helps to boost the mitochondria in your cells improving your strength and stamina.

You may even want to raise what’s called your lactate threshold. You’ll be able to keep pushing further, develop your aerobic capacity, and demolish your next workout.

Try our Hot Body HIIT challenge to jump-start your week and feel awesome.