My body is doing what?

My Body Is Doing What?!

Why is my heart rate spiking up all of the sudden!?

Have you ever heard of cardiac drift?

For one thing it's not your heat rate during a wild street race...
 

Cardiac Drift is defined as: Cardiovascular drift (CVD) is the phenomenon where some cardiovascular responses begin a time dependent change, or "drift" after around 10 minutes of exercise in a worm or neutral environment. It is characterized by the decreases in mean arterial pressure and stroke volume and a parallel increase in heart rate. It is influenced by many factors, most notably the ambient temperature, hydration and the amount of muscle tissue activated during exercise. To promote cooling, blood flow to the skin is increased, resulting in a shift in fluids from blood plasma to the skin tissue. This results in a decrease in pulmonary arterial pressure and reduced stroke volume in the heart. To maintain cardiac output at a reduced pressure, the heart rate must be increased.

But what in the world does this mean? And what's happening in my body?!
 

Here is a simple version of what is going on in your body:

• When you are performing aerobic exercise your body has to get oxygen rich blood to your muscles that are working so that the mitochondria in your muscles cells can produce energy to cause your muscles to contract and move. (Mitochondria are known as the "powerhouses" of your cells, taking in nutrients and breaking them down to create energy for the cells).
• While exercising your body is going to generate heat as a byproduct, as humans are not very efficient. Couple this with a hot and humid environment, and you will begin to sweat and possibly sweat profusely. When you are sweating you are using fluid in your body to cool down through condensation. That fluid is no longer available to be used in the blood stream.
• As you continue to sweat your blood becomes "thicker", imagine which would be easier to push through a straw water or spaghetti sauce? Your body's demand for oxygen has not changed (given you stay at the same workload) so the only way to get the same amount of oxygen to your muscles is to have the heart pump faster.
• Your heart rate will spike up and bring you closer to your maximal heart as your body is trying it's best to bring oxygen to your muscles!

 

Now how does this affect you?? Cardiac drift can shorten your workout and bring you close to your maximal heart rate which has it's own dangers during exercise as well.

 

Tips on how to avoid Cardiac drift:

 

• Stay properly hydrated before and during your exercise.
• Avoid exercising in hot and humid environments.
• Wear sweat wicking clothing and avoid cotton clothing.