1 / 12

Integration of Cardiovascular and Respiratory Function

Integration of Cardiovascular and Respiratory Function. Oxygen Consumption (VO 2 ). Oxygen consumption is the amount of O 2 taken up and consumed by the body for metabolic processes It is equal to the amount of oxygen inspired minus the amount of oxygen expired

lesley-schneider
Download Presentation

Integration of Cardiovascular and Respiratory Function

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Integration of Cardiovascular and Respiratory Function Oxygen Consumption (VO2) • Oxygen consumption is the amount of O2 taken up and consumed by the body for metabolic processes • It is equal to the amount of oxygen inspired minus the amount of oxygen expired • VO2 is proportional to workload • VO2 (L/min) = [VI (L/min) x %O2 inspired] - [VE (L/min) x %O2 expired]

  2. Oxygen Consumption (VO2) • Theoretically, VO2 is a function of both O2 delivery to and O2 uptake by the working muscle and other tissue • Another way to describe O2 uptake is a-vO2diff, which represents the average amount of O2 in the arteries minus the average amount of O2 in the vena cava • Described mathematically by the Fick Equation • VO2 (L/min) = (SV x HR) x [a-vO2diff (mlO2 / 100 ml of blood)]

  3. Oxygen Consumption (VO2) • Therefore, the maximal rate of oxygen consumption (VO2max) would theoretically occur at maximum SV, HR, and a-vO2diff • VO2max is more properly defined as the maximal amount of O2 that can be taken in and used for the metabolic production of ATP during exercise • To determine VO2max in the lab, VO2 is measured using a metabolic cart and computer system, while the participant performs incremental exercise to exhaustion

  4. Oxygen Consumption (VO2) • Such exercise can be performed using either a cycle ergometer or a treadmill • VO2 max is used as a measure of aerobic fitness, and is indicative of aerobic exercise performance • VCO2 is calculated by measuring the difference between the amount of CO2 expired and inspired • The amount of CO2 produced and O2 consumed varies depending on the type of fuel being used by the working muscle

  5. Oxygen Consumption (VO2) • When fat is being oxidized and used to produce ATP, more O2 is consumed as compared to the amount of CO2 produced • When carbohydrate is the major fuel used to produce ATP, not as much O2 is consumed relative to the amount of CO2 produced • When only carbohydrate is being used, the ratio of VCO2 to VO2 is equal to 1 • RER is close to 0.7 when the main fuel being used is fat • Therefore, RER allows a way to estimate relative contribution of the different fuels used in skeletal muscle during exercise

  6. Limiting Factors for VO2max • The respiratory system could potentially limit VO2max through (a) inadequate ventilation and (b) oxygen diffusion limitations • The cardiovascular system could limit VO2max because of (a) inadequate blood flow and/or cardiac output, or (b) inadequate oxygen-carrying capacity (hemoglobin concentration) • Within the working muscle, a lack of mitochondria and the metabolic systems involved with the useof O2 could also potentially limit VO2max

  7. Limiting Factors for VO2max • Exercise physiologists are supporting the notion that it is the cardiovascular system that limits VO2max in healthy people • It appears that the cardiovascular system is unable to meet the demands of the working muscle and deliver an adequate amount of O2 • The limitation to VO2 max within the cardiovascular system appears to be related to cardiac output (Q)

  8. VO2max for Various Sports

  9. The Rest to Exercise Transition • During incremental exercise, pulmonary ventilation initially increases at a rate proportional to the increase in workload • Eventually, a point is reached where ventilation increases much more rapidly than workload • This point is called the VENTILATORY THRESHOLD, and it normally occurs at about 65-85% of VO2 max, depending on the individual’s level of fitness • Increase in ventilation thought to occur because of an increase in LACTIC ACID ACCUMULATION in the blood

  10. The Rest to Exercise Transition • The energy demands of the exercise can no longer be met by only the aerobic metabolic systems • Hence, the anaerobic system are also used to meet the increasing energy requirements of the exercise • Eventually, a point is reached where blood lactate concentrations rise exponentially, resulting in very high concentrations • This point is referred to as the LACTATE THRESHOLD

  11. Lactate Threshold

  12. The Rest to Exercise Transition • When blood lactate levels begin to accumulate rapidly, this is referred to as the ONSET OF BLOOD LACTATE ACCUMULATION (OBLA) • With proper aerobic training, the OBLA curve can be shifted to the right such that OBLA occurs later and during higher levels of intense exercise

More Related