Old Wives' Tales - The Lactate Threshold
Intense exercise causes lactic acid levels to build up faster than the body can metabolize it. For athletes, this can be good because in the process of generating lactic acid, energy for muscle is also being generated. However, Dr. Joyner says, there are some misperceptions about lactate levels. Specifically:
* Lactate is not synonymous with muscle hypoxia: "The first misperception is that somehow people don't have enough oxygen when they are making lactic acid. That certainly can be true because lactic acid can come from a lack of oxygen, but under most circumstances the athletes have plenty of oxygen and there is plenty of oxygen in the muscle."
* Lactate is gone from the muscle in the 15 to 30 minutes after exercise and does not make you sore: "The second misnomer is that lactic acid hangs around in your muscle for long periods of time. You may hear things like this individual is sore or not performing as well today because they have a lot of lactic acid in their muscle from yesterday's event. Well, you can have very high levels of lactic acid in muscle, but it's gone 15 to 30 minutes after exercise - so lactic acid doesn't hang around a long time."
* Breathing oxygen on the sidelines does not help enhance lactate levels: "Breathing oxygen on the sidelines really doesn't help - there's no evidence that it works."
How well your muscles use oxygen and how well they can metabolize
glucose without producing a lot of lactic acid in the skeletal muscle
(which can contribute to fatigue) are both important for performance, Dr.
Joyner says. However, how much speed you can generate at the lactate
threshold is also important. This is known as running efficiency or running
|SOURCE Mayo Clinic|
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