Interval Training: Are you getting anything out of yours?

Following up on the heels of my last post regarding endurance training and long slow distance, I want to spend a minute talking about interval training itself.  As a quick recap, in order to get faster you must provide the body with a training stress large enough to disrupt your body’s homeostatic balance. Running the same long distance over and over and expecting improvement in speed will not suffice as the body adapts to this distance (and this speed).  Therefore, interval training is required to give the body the disruption that it needs in order to initiate a response and create an adaption via improving your VO2 Max.  VO2 Max can be simply defined as the rate of exercise where the heart and lungs have their maximum ability to deliver oxygen to working muscle. Improving this then allows for you to go faster for longer.

But here’s the catch, and I would be willing to bet that a lot of you reading this right now fall into this trap.  These intervals have to be efforts ABOVE your current VO2 Max in order to initiate the homeostatic disruption response.  Which means you likely aren’t doing them fast enough right now. AND, once you adapt to THAT effort you have to take your intervals even FASTER.

The quick and dirty scientific explanation:
When someone becomes “winded” in exercise it is because their heart and lungs are not able to keep up with the oxygen demand of the muscles.  Not only do the heart and lungs need to deliver this oxygen , the muscle cells must extract the oxygen from the blood and use it in a conversion process to produce usable energy. All this must occur in a rate and time dictated by the intensity of exercise.  Oxygen molecules bind to hemoglobin in the blood as a delivery mechanism.  In a normal, healthy resting person, oxygen saturation of the blood is between 97-99%.  During exercise we lower our oxygen saturation of the blood. During efforts above delivery capacity (above VO2Max) we lower our oxygen saturation to very low levels (94% or below).  When our levels drop these very low levels we have to slow down significantly or stop.  The good news is this creates a homeostatic disruption in the body which means we adapt to the effort that caused this disruption and thus get stronger.  But, again, the catch is: these efforts MUST be intense enough to drop oxygen levels enough to trigger an adaptive response.

Taking your intervals PAST the edge of discomfort to create complete body distress is the only way to see significant gains in speed and fitness.  It’s not up for debate- it’s science.

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