Exercise Physiological Tests - Term Paper Example

Graded Incremental Exercise Tests (GXTs) are used to evaluate aerobic endurance performance capacity. An exponential rise in blood lactate concentration during GXTs can be observed (Eston and Reilly 2001). The resulting lactate curve is translated into endurance capacity. A rightward shift of the lactate curve (lower by a given workload) can be interpreted as an improved endurance capacity and in contrast, a shift to the left (higher by a given workload) is considered worsening endurance capacity.

Evidence shows that methods that analyze changes in bLa during GXTs are favorable compared with the use of absolute lactate values. However, there are also studies showing that specific GXT protocol has the potential to vary considerably in starting and subsequent work rates, work rate increments, and stage duration.     The disadvantage of this test is that it is dependent on several other methodological issues thus test result must be carefully interpreted. Additionally, the method of blood extraction and the body part where the blood is extracted, show differences in results.

The overall lactate levels are also known to be influenced by depleted glycogen stores that may be accounted to a low carbohydrate diet or preceding exhaustive exercise. Factors like muscle fiber composition, glycolytic and lipolytic enzyme activity and, capillary and mitochondrial density may also influence blood lactate curves. The study of Lee et al. (2003) suggested that physical activity recommendations must be customized according to the individual and that the global requirements for activities of more than ≥3 METs (metabolic equivalents) may be invalid especially to older persons.

This means that the relative intensity of physical activity or the perceived level of exertion when exercising showed to be effective to the health status of a person rather than using the absolute scale.  The absolute scale that is used to classify the intensity of the activity is calibrated on the physical effort required, and not on the ability that a person has. It is important to note that the energy required by an individual to perform an activity is relative to his physical fitness.