Physiologic Warm Up06/17
“Second Wind” is another physiological process relevant to your walking-pace. “Second wind” involves the physiological adjustments your body makes during the first 15-20 minutes of your walking-trial. These adjustments include changes in muscle temperature, changes in muscle blood flow, and the onset of sweating.
Muscle Temperature Changes
At rest, your muscle temperature is the same as your body temperature: 98.6°F. Since heat is a by-product of muscle contractions, your muscle temperature increases when you start to exercise. After 15-20 minutes of exercise, your body temperature increases to about 102°F and warms up the muscle fibers to an optimal level for muscle contractions.
Blood Flow Redistribution
After about 15-20 minutes of exercise, when your body reaches its warmed-up temperature (cells in the skin give off beads of water and evaporate). This evaporation process cools the body and reduces the need for blood flow to the skin. The skin is then able to redistribute some of its blood flow to your active muscle tissue, thus enhancing your muscle blood flow and providing extra glucose and oxygen and washing out accumulating metabolic fatigue products.
“Second wind” is the effects of warming-up your active muscles, the onset of sweating, and redistribution of blood flow to your active-muscle fibers. The combined effects of these three variables produce a feeling of maximum-walking efficiency.
Losses in cardiovascular muscle strength produce sedentary lifestyles and increase CAD risk