B4

Exercise and Respiration

Define VO2 and VO2max

• VO2 – An expression of the rate at which oxygen is used by tissues, usually given in microliters of oxygen consumed in 1 min by 1 milligram dry weight of tissue.

• VO2max - VO2 max refers to the maximum amount of oxygen that an individual can utilize during intense or maximal exercise. It is measured as "milliliters of oxygen used in one minute per kilogram of body weight."

Graph of VO2max

Gas analysis for VO2max

Outline the roles of glycogen and myoglobin in muscle fibers

Outline the method of ATP production used by muscle fibers during exercise of varying intensity and duration

• Creatine phosphate as an energy source:

Creatine phosphate + ADP creatine + ADP

CP found in muscle fibers but only in conc that allows for 8-10 secs of ATP production during vigorous exercise

After 10 secs of vigorous exercise?

• ATP produced entirely by cell respiration (CR)

Evaluate the effectiveness of dietary supplements containing CP in enhancing performance

Supplementation attempts to increase [ CP ] in muscles = performance during high intensity exercise

Sig. increases only occurs in individs with low [ CP ] tp begin with

Appears more likley gain in water retention that CP levels which = decrease in athletic performance

Outline the relationship between the intensity of exercise, VO2max & the proportions of carbohydrates & fat used in

respiration

• During exercise, we use a combination of these energy sources.

• At a high intensity the main source of energy is carbohydrate and at a low intensity fat is the predominate source.

• As there is a limit to the amount of carbohydrate that can be stored in the muscles, high intensity work can only be sustained for short periods. We have large stores of fat so low intensity work can be maintained for long periods.

The following table, adapted from O'Neil (2001)[1], shows the relationship between exercise intensity (% of your Maximum Heart Rate) and the energy source (carbohydrate and fat)

.

Intensity % MHR % Carbohydrate % Fat

65 to 70 40 60

70 to 75 50 50

75 to 80 65 35

80 to 85 80 20

85 to 90 90 10

90 to 95 95 5

100 100 0

The following table, adapted from O'Neil (2001)[1], shows the relationship between exercise Intensity (% of your Maximum Heart Rate) and the energy source (carbohydrate and fat).

•State that lactate produced by anaerobic cell respiration is passed to the liver for processing and creates an oxygen debt

Outline how oxygen debt is repaid

• Lactate is turned into pyruvate, which is converted into glucose or used in aerobic respiration in the mitochondria…..using oxygen taken in during deep ventilation during exercise