I hammered it to death in our last live class, so, as promised, here is my explanation of HIF-1!

What is it? Hypoxia Inducible Factor

Ultimately, this is the little transcription factor that scurries over to your nucleus and knocks on the door to say, “Hello, can you please create the instructions to upregulate ADDITIONAL factors that will help us to PULL in more oxygen?” The nucleus says, “Sure, no problemo!” And within a fairly short period of time, we see increases in EPO (erythropoietin), VEGF (vascular endothelial growth factor), amongst other factors, that increase our ability to get more oxygen in when we have placed ourselves in a training environment that has lower amounts of oxygen available (whether that is from being at altitude, in a hypoxic chamber, or breath retention).

By combining a greater oxygen demand on the body through moderate to high intensity exercise, in conjunction with a reduction in available oxygen, we see higher spikes in these factors, and therefore, more significant adaptations. For example, a cyclist is going to see a greater rise in red blood cells and oxygen utilization when training at altitude vs. sitting at altitude. The same is true for apnea training in conjunction with movement. Your muscles are demanding oxygen, while you are simultaneously reducing the available oxygen. Do your muscles get less oxygen? NO! They ultimately end up receiving more oxygen through the Bohr Effect (hemoglobin has less affinity for oxygen as CO2 rises in the body and it OFFLOADS the O2, which then becomes available to your active tissues!).

You may see your blood oxygen (SpO2 on pulse oximeter) drop, but this does not mean that your muscles are not getting what they need. In fact, we end up reverting to a high level of anaerobic glycolysis (without oxygen) when you feel the lactate and CO2 rise in your body on those breath holds during exercise. With that, comes the positive adaptations that we see, such as greater muscle buffering capacity, when exposing ourselves to high intensity exercise, but at a much lower intensity. For more detailed science on what is happening during Hypoventilation training, please refer to the master Dr. Xavier Woorons, as his lab has been working on this style of training for decades.

See you in class TONIGHT MONDAY!
AJ