See the related article: “Turn Down That Stereo!”
Why does it take a period of time before you feel warmed up and comfortable after starting a run?
The answer begins with how your body responds to the increased demands of exercise. When you start exercising, your body must do the following:
- Increase the rate of oxygenation of blood and removal of carbon dioxide waste products (respiration);
- Increase the amount of blood flow to the muscles of the body (cardiac output); and
- Increase the energy supply to the muscles to meet the demands of exercise.
These events do not happen immediately. Let’s look at each one of the above elements.
- Controlled by the nervous system;
- Is the process of ridding the body of carbon dioxide and getting more oxygen into the bloodstream for aerobic energy production.
Increased Cardiac Output
- Controlled by sympathetic nervous system (the fight-or-flight response);
- Most limiting factor in performance;
- Cardiac stroke volume, which is how much blood your heart can pump with each beat, is what improves the most with training; and
- Cardiac output is defined as stroke volume multiplied by heart rate, which gives you blood flow in liters per minute.
- Aerobic training primarily relies on fat burning and oxygen to produce energy;
- Aerobic energy production has greater capacity than anaerobic systems, but is produced at a slower rate; and
- The trigger to start aerobic energy production is not fully understood. It appears to involve neurological stimulation that triggers the release of signaling proteins, neurotransmitters and hormones.
It takes time for all these systems to come “online” to meet the increased demands of exercise. So begin slowly until the body reaches its peak energy efficiency. As your body ramps up its energy production, you can ramp up your pace accordingly.
In summary, running initiates a neurological cascade of events leading to increased respiration, heart rate and a release of signaling proteins, neurotransmitters and hormones. This latter process leads to increased aerobic metabolism. The exact series of events is still unclear, but it is the metabolic changes that take the most time.