Buzz
The phrase “Feel the burn!” is frequently used to push individuals to exercise more intensely and for longer durations than usual. While many embrace this discomfort as a sign of progress, it’s not always a dependable measure of an effective workout. This article explores why relying on the “burn” might be overrated and what truly matters in fitness.
Lactic Acid Isn’t the Culprit
Many believe the burning sensation in muscles during intense exercise is caused by lactic acid buildup, often referred to as lactic acidosis. This theory was widely accepted for years, especially in activities like high-intensity interval training or high-repetition weightlifting. However, recent studies have debunked this idea, showing that the explanation doesn’t align with current scientific understanding.
The confusion arises from the fact that the body produces lactate, not lactic acid. Although the terms are often used interchangeably, their chemical structures differ significantly. While higher exercise intensity correlates with increased lactate levels and reduced performance, lactate itself isn’t the direct cause of the burning sensation or muscle fatigue. Interestingly, some researchers are now investigating alternative explanations that could even exonerate lactate.
For example, a study published in the Journal of Applied Physiology reveals that lactate alone does not significantly contribute to muscle fatigue or hinder a muscle’s capacity to keep functioning. So, what’s the real cause? According to a detailed paper in the American Journal of Physiology, during intense exercise, a separate reaction occurs alongside energy and lactate production, leading to an increase in hydrogen ions within muscle cells. This buildup of hydrogen ions raises acidity levels, which is responsible for the burning sensation many fitness enthusiasts celebrate.
In a surprising turn of events, lactate, once vilified, actually helps delay muscle fatigue instead of causing it. It does this by aiding in the removal of hydrogen ions through its formation, thereby reducing the acidity in muscle cells. Essentially, without lactate, your muscles would tire out much more quickly.
As it turns out, lactate isn’t the villain it was once made out to be; it’s more of a misunderstood ally.
Why “The Burn” Isn’t as Beneficial as You Think
Fitness often fosters a peculiar mix of love and hate for discomfort—whether it’s excessive sweating, fatigue, soreness, or the infamous “burn.” Yet, this discomfort is often seen as a necessary step toward achieving rewards.
Although the burning sensation can escalate from uncomfortable to excruciating, many individuals actively pursue this feeling. While it may motivate them to keep exercising, it creates a harmful cycle that reinforces the flawed idea that exercise should feel like punishment. (Spoiler: It shouldn’t.) Beyond the #Fitspiration nonsense, relying on such metrics to measure workout effectiveness is counterproductive. As JC Deen, a frequent Mytour contributor and personal trainer, explains:
Chasing the burn solely to
feel
like you’ve had a productive workout is meaningless without clear goals. For instance, if your aim is to maximize strength, intense high-rep training is counterproductive because it severely hampers recovery and your ability to maintain consistent workouts.
We’ve already debunked the myths that attribute muscle burn and post-exercise soreness, or delayed onset muscle soreness (DOMS), to lactate. Interestingly, deliberately inducing muscle burn doesn’t always result in the soreness typically associated with muscle damage, growth, and repair. In reality, soreness is more likely to occur from eccentric contractions, such as running downhill or lowering a weight during a bicep curl, even without any noticeable burning sensation during the activity.
While some may use the burn as a flawed indicator of effort, a more effective method is the Rate of Perceived Exertion (RPE) scale. As detailed in our article, the RPE scale allows you to rate your effort and intensity on a scale of 1 to 10. Ratings 7, 8, and 9 include subtle adjustments that can influence how much you push yourself. Though not flawless, this scale offers better guidance for regulating workout intensity based on how you feel, rather than pushing yourself to exhaustion every time.
Additionally, if you’re constantly extremely sore or feel awful after workouts, it could discourage you from exercising regularly or lead to consistently underwhelming performance.
When “The Burn” Can Be Beneficial
There are indeed scenarios where experiencing the burn can be advantageous, such as when you aim to feel your muscles engaging and contracting effectively (often referred to as the mind-muscle connection), enhance muscle size, or boost overall fitness through methods like high-intensity interval training (HIIT).
Recent studies on lactate, such as those summarized in this review article in The Scientific World Journal, reveal that lactate serves as a versatile and efficient energy source for various cells in the body. Contrary to the old belief that lactate is only used during oxygen deprivation, it is also utilized during moderate to intense exercise and even at rest. As you train harder and increase lactate levels, your body adapts to better absorb and utilize lactate, along with other energy sources, to fuel your activities.
Muscle growth depends on several key factors, as highlighted by hypertrophy expert Brad Schoenfeld: muscle damage, metabolic stress, and mechanical tension. In simpler terms, these can be thought of as post-workout soreness, the burning sensation, and the effort of lifting heavy weights, respectively.
In a review article published in Sports Medicine, Brad explored metabolic stress and its various mechanisms for promoting muscle growth. He noted that pushing through the burn can be effective for building larger muscles and improving overall performance. (To clarify, Brad references a bodybuilding concept called “the pump,” which is similar but not identical to the burn.) As JC explains, “It can serve as useful feedback that you’re generating the muscle damage needed to trigger the growth and adaptations you’re aiming for.”
“Pursuing the burn is only worthwhile if it aligns with your program and serves a specific purpose,” JC adds. Activities like high-rep training, HIIT, circuit training, supersets, and similar methods can be effective when used appropriately.
Understand When to Push Hard and When to Rest
If you’re dealing with significant life stress, feeling exhausted due to lack of sleep or recovery, already exercising intensely, or managing previous injuries, there’s no benefit in constantly pushing your muscles to their limits. The true goal of a workout isn’t to induce a burning sensation but to build consistent habits that lead to lasting physical and mental improvements. This approach allows you to train more regularly, reap the rewards of exercise, and avoid unnecessary discomfort.
Keep in mind that our bodies aren’t machines with predictable inputs and outputs. Short-term muscle burn or soreness isn’t essential for maintaining fitness. What truly matters is ensuring proper recovery from your workouts to support both your immediate and long-term fitness objectives.
Title image by grmarc. (Shutterstock)
