“Restlessness is discontent, and discontent is the first necessity of progress.” Thomas Edison

Lactate Threshold and why is it important to warm-up?

There have been many reasons given for warming up prior to a race or hard workout.  But, what’s the physiological reason to warm-up.  Lactic Acid!

When you start a hard workout or race the lactate levels will increase.  This will occur even if you’re not working that hard.  This is because the blood flow to your muscles is not yet sufficient to provide the necessary oxygen to complete the Krebs cycle and complete the breakdown of pyruvate into carbon dioxide and water (and releasing huge amounts of energy). 

As the pyruvate accumulates in your muscles it is converted to Lactic Acid and begins to enter your blood.  Studies have shown surprisingly high levels of Lactate even when working at a fairly moderate rates.

This is due to two physiological actions.  First, your heart rate will not yet be high enough to deliver sufficient blood to your muscles.  Second, the capillaries will not be dilated fully, further restricting the amount of oxygen rich blood being delivered to your muscles.

As you continue to work at a moderate rate, your heart rate increases and your capillaries dilate delivering large amounts of oxygen to your muscles.  The pyruvate and Lactic Acid will then be fully oxidized for energy.  Your blood lactate levels will then drop!

If you continue to work hard or increase your effort, the Lactic Acid levels will begin to rise again.  The limiting factors in the complete breakdown of Lactic Acid is not the lack of sufficient oxygen.  It is the lack of sufficient enzymes to handle the pyruvate oxygenation process or because your muscles lack enough mitochondria (these are the structures in your muscles that are involved in the Krebs cycle).

When the speed at which you can complete the breakdown of Lactic Acid falls behind the speed at which you are producing Lactic Acid, you have reached your Lactate Threshold (LT).  The speed your are swimming, cycling or running at when this happens is your LT velocity.  This is the speed at which Lactic Acid begins to again appear in your blood.

You of course could start off slowly and use the beginning of your workout or race to allow these physiological processes to get up to speed.  Or you could do a good warm-up to get your physiological systems fully active before you begin your hard work or race.

The warm-up is equally important in hot weather as it is in cold weather. 

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