Topic: The Importance of a Warm-Up & Cool-Down (and the science of why)

What defines a Warm-Up?
+ A warm-up prepares the body for activity by elevating the body temperature.

The best type of warm-up is specific to the activity that will follow and also individualized as to not produce fatigue. In addition, we know that a warm-up is important to the ligaments and tendons of the body as to allow a greater compliance of movement after heat and mobility are introduced into such areas.

Cardiovascularly speaking, a warm-up allows the body to adjust to the demands of exercise. At rest, the skeletal muscles receive ~15-20% of blood pumped from the heart; during moderate exercise they receive ~70% of cardiac output. This increased blood flow is important in warming the body since the blood carries heat from active muscles to the rest of the body.

A warm-up of between 5 and 10 minutes should precede any bout of exercise regardless of how intense or mundane. For many activities, the warm-up simply continues into the aerobic portion of the exercise session. For example, starting off walking at a comfortable pace for 5-10 minutes before starting to jog or run (science of why - read on).

Further benefits of a warm-up to the cardiovascular system:
-Increases blood flow to active skeletal muscle
-Increases blood flow to the myocardium (muscle of the heart)
-Increases the dissociation of oxyhemoglobin (oxygen separated from its hemoglobin carriers in the blood, therefore more oxygen available for working muscles)
-Leads to earlier sweating, which plays a role in thermoregulation (maintaining a homeostatic body temperature)
-May reduce the incidence of abnormal heart rhythms (dysrhythmias), which can lead to abnormal heart function

Generalizations of benefits of a warm-up metabolically speaking:
-Elevated body temperature (muscle temperature) increases the rate at which the metabolic processes in the cell can proceed
-Oxygen is more readily released from red blood cells and transported into the mitochondria (site of aerobic energy production) at elevated temperatures
-Greater availability of oxygen to the muscles during work; which when more oxygen is available sooner, less reliance is placed on anaerobic metabolism, and thus less lactate accumulates at any given heavy workload. Lighter endurance workloads early on in the exercise session (aka a warm-up) utilize more fats for the production of energy, sparing carbohydrates and extending the time a given high-intensity effort can be continued.


What defines a Cool-Down?
+ A cool-down allows for a gradual return to normal body temperature.

The cool-down period should follow the conditioning period of the exercise session. The primary cardiovascular advantage to a cool-down period is that it prevents venous pooling (accumulation of blood in the veins of the extremities, namely the legs and feet), and thus reduces the risk of fainting by keeping the skeletal muscle pump (from the lower extremities up towards the trunk and returning into the heart) active when the venous system is dilated immediately post-exercise.

The primary metabolic importance of a cool-down is that lactate (by-product of anaerobic contribution to high-intensity aerobic exercise) is dissipated faster during an activity recovery (read: not sitting down immediately post-exercise). While a lactate removal rate is maximized after approximately 20 minutes, lower intensity exercise sessions would benefit sufficiently from a ~10 minute cool-down.

Important message to take from this entry: a warm-up and cool-down are essential to include in any exercise session; regardless of it's nature.

You have read the science behind some of the reasons, now just be sure to integrate what you've learned. Look forward to more suggestions for topics. Thank you!

Submitted by Al Smith, HAPLab Manager