Topic:The Importance of Cardiorespiratory Exercise

+What is Cardiorespiratory Fitness?

-The ability to deliver and use oxygen under the demands of intensive, prolonged exercise or work.

Any activity that involves large muscle groups and is sustained for prolonged periods of time has the potential to increase cardiorespiratory fitness. Examples: aerobics, bicycling, cross-country skiing, dancing (in various forms), jogging/running, roller blading, rowing, speed skating, stair climbing or stepping, swimming, hiking, and walking.

Other names associated with cardiorespiratory exercise: aerobic endurance training.

Benefits of Cardiorespiratory Exercise:
-Enhanced central (adaptations that occur in the heart and contribute to an increased ability to deliver oxygen) and peripheral (adaptations that occur in the vasculature or the muscles that contribute to an increased ability to extract oxygen) cardiorespiratory functioning
-increase in functional capacity (also shown as an increase in VO2max)
-increase in ventricular filling and high stroke volume and cardiac output
-increase in coronary vascular bed size (thus, greater ability to provide the myocardium or muscle of the heart with more O2 rich blood)
-increase in blood volume (due to an expansion of plasma volume)
-decrease in resting heart rate
-decrease in TPR (total peripheral resistance) at maximal exercise
-increase in active muscle blood flow during maximal exercise
To name a few...

Good news for men and women alike: evidence suggests that there is no difference between gender in central and peripheral adaptations to aerobic endurance training!

Take-Home Message:
3 to 5 days a week of 20 to 60 minutes worth of cardiorespiratory exercise over the course of a few months to a year will certainly allow you to demonstrate many if not all of the aforementioned benefits. Reasons to not exercise in some form or fashion (of which good examples of how to get aerobic exercise are listed above!!) is certainly to submit to premature death and/or health complications now or later in life.

The only excuse is the one you make up!

Treat yourself to some lovely Gunny weather of sunshine, blue skies, and warm temperatures. Your heart and other related body systems will thank you! Till next time...

Submitted by Al Smith, HAPLab Manager

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