Stories
Debunking the Burn: Lactic Acid Not to Blame for Workout Pain
- •The familiar "burn" during intense exercise has long been attributed to lactic acid buildup, a belief that is scientifically incorrect.
- •The myth originated from early 1900s research on amphibian muscles, which observed lactic acid accumulation alongside fatigue, leading to a misapplication of cause-and-effect.
- •Lactic acid cannot exist in the body; it breaks down into lactate and hydrogen, with lactate actually reducing muscle acidity and serving as fuel.
- •The burning sensation is caused by increased stimulation of nerves in and around muscles, which detect various substances produced during intense exercise.
- •Post-workout muscle soreness is also not caused by lactic acid or lactate, as lactate levels return to normal within 30-90 minutes, long before soreness peaks.
Key Questions Answered
The burning sensation is caused by the increased stimulation of specialized nerves in and around the muscles that detect substances produced during exercise. These nerves connect to brain areas responsible for pain and emotional responses, firing faster as you exercise harder and produce more of these substances.
The myth originated in the early 1900s when scientists observed that lactic acid accumulated in the stimulated, fatigued muscles of amphibians. Although this early work never explicitly claimed lactic acid caused fatigue, a misapplication of cause-and-effect led to the creation of the lactic acid theory.
Lactate actually decreases muscle acidity rather than increasing it. Because lactic acid cannot exist in normal body pH and breaks down into lactate and hydrogen, lactate production consumes hydrogen and helps make muscles less acidic so you can exercise harder for longer.
