FitMet

Part 2 of a multi-part series.

By John Kruse

Part 1: Cardiovascular Fitness

Cardiovascular fitness is known by many names such as as aerobic fitness, cardiovascular function, aerobic capacity, cardiovascular endurance, maximal oxygen consumption and VO_2max. Essentially, it is the body’s ability to use oxygen. A person with excellent cardiovascular fitness can use a higher volume of oxygen that is brought into the body from the air that they breathe. A person who is lacking cardiovascular fitness uses a lower amount of oxygen from the air that they breathe. Oxygen is essential for life and the physical work that we do. This physical work can be activities of daily living, manual labor or physical exercise.

All of our activities, including sleeping require oxygen. This is because our muscles require oxygen to contract. These contracting muscles require more oxygen for higher workloads. In the laboratory, we can measure the amount of oxygen that is required for exercise. This measurement is called VO₂. The V stands for volume and the O2 stands for oxygen the dot over the V stands for rate. Fitter individuals require less oxygen for a given workload than less fit people since their bodies are more efficient at using the oxygen that is taken into the body.

Maximal Oxygen Uptake

We measure aerobic fitness and express it in terms of VO_2max. At maximal workloads VO_2max is the measure of how much oxygen is being used by the body. In other words, it is the maximum amount or volume of oxygen that a person can utilize during maximal exercise. This is expressed as an absolute measure in liters per min (L/min), or as a relative measure in milliliters per kilogram per minute (ml/kg/min).

According to DeVries, VO_2max either measures directly or indirectly the following:

1. cardiovascular function,
2. respiratory function,
3. muscular efficiency,
4. strength,
5. muscular endurance,
6. and, obesity (since VO_2max is usually expressed in milliliters of O2 per kg of body weight)

Why is Cardiovascular Fitness Important?

According to Brooks et al., cardiovascular fitness is the single most important measure of fitness for physical educators:

…realization that physical work capacity, VO_2max, and cardiovascular fitness are interrelated has resulted in a convergence of physical education (athletic performance) and medical (clinical) definitions of fitness. From the physical education—athletics perspective, cardiovascular function determines VO_2max, which in turn determines physical work capacity, or fitness. From the medioclincal perspective, fitness involves, minimally, freedom from disease. Because cardiovascular disease is the greatest threat to the health of individuals in contemporary Western society, medical fitness is largely cardiovascular fitness…. In fact, VO_2max is so important form both the physical education—athletics and medioclinical perspectives, it has emerged as the single most important criterion of physical fitness.

Coming up: How do you measure VO_2max in a physical education environment?

Tags: cardio, metrics, VO2max

This entry was posted on Wednesday, January 14th, 2009 at 8:30 am and is filed under Cardiovascular, Cardiovascular Fitness Content (4 parts), Standards. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.