Lie #2: Lactic Acid Causes Muscle Fatigue
Most athletes believe that lactate (as we’ll call it from now on) causes muscle fatigue by making the muscles too acidic to contract effectively. This is not true. While the muscles do become more acidic during exercise, lactate is not the cause. In any case, far from hastening fatigue, lactate accumulation in the muscles actually delays fatigue by mitigating the effects of a phenomenon known as depolarization. During intense exercise, your muscles lose power in the same way a battery does: by becoming depolarized. The accumulation of lactate in muscle tissue during intense exercise partly counteracts the effect of depolarization.