* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download cardiac output
Intracranial pressure wikipedia , lookup
Hemodynamics wikipedia , lookup
Homeostasis wikipedia , lookup
Biofluid dynamics wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Circulatory system wikipedia , lookup
Weight training wikipedia , lookup
High-altitude adaptation in humans wikipedia , lookup
Common raven physiology wikipedia , lookup
Cardiac output wikipedia , lookup
Haemodynamic response wikipedia , lookup
Organisms at high altitude wikipedia , lookup
Neurobiological effects of physical exercise wikipedia , lookup
ACE Group Fitness Instructor Manual Chapter Exercise 1 Physiology ADAPTATIONS TO EXERCISE 1 Cardiorespiratory adaptations during acute aerobic exercise Increased heart rate (HR) Increased stroke volume (SV) SV is the amount of blood pumped from each ventricle each time the heart beats. SV is measured in milliliters (mL) per beat. 2 Cardiorespiratory adaptations during acute aerobic exercise Increased cardiac output Cardiac output = HR x SV A typical cardiac output at rest: 60 bpm x 70 mL/beat = 4,200 mL/min (approximately 1 gallon of blood per min) During maximum exercise, cardiac output can increase up to 4 to 7 times above resting level. 3 Cardiorespiratory adaptations during acute aerobic exercise Increased breathing rate Increased systolic blood pressure This increase is due to the cardiovascular system attempting to increase oxygen delivery to the working muscles. However, blood pressure greater than 250/115 mmHg is an indication to terminate exercise (hypertensive response). 4 Cardiorespiratory adaptations during acute aerobic exercise No change, or a slight decrease, in diastolic blood pressure This is due to the dilation of vessels in the muscles and the skin. Vasodilation decreases peripheral resistance. This is an important benefit for individuals suffering from heart disease, hypertension, diabetes, and peripheral vascular disease. 5 Cardiorespiratory adaptations during acute aerobic exercise Blood is shunted from the viscera to the working muscles Partly caused by the dilation of vessels that supply blood to the exercising muscles Partly caused by the constriction of vessels that supply blood to the abdominal area 6 Cardiorespiratory adaptations during acute aerobic exercise Increased extraction of oxygen from the blood into the working tissues An average healthy person is able to load the blood with more oxygen in the lungs than he or she is able to use at the cellular level. Therefore, the more efficiently an individual can extract oxygen from the hemoglobin in the capillaries, the more physical performance improves. 7 Oxygen extraction •Oxygen enters lungs. •Oxygen loads onto hemoglobin in blood and is transported to the working muscle. •Oxygen is unloaded into muscle cell. •Oxygen loads is transported to mitochondria. •Mitochondria grow and multiply with regular exercise to increase metabolic capacity. Acute Responses to Aerobic Exercise Oxygen consumption during exercise •Oxygen deficit. •Steady State •EPOC (excell post exercise oygen consumption. Copyright © 2007 Lippincott Williams & Wilkins Figure 4.7 Acute Responses to Aerobic Exercise Lactate Threshold Also known as anaerobic threshold (AT). The point at which blood lactic acid suddenly rises during incremental exercise Characterized by feeling “out of breath” and feeling a burning sensation in the working muscles. Can be used as a marker of exercise intensity Acute Responses to Aerobic Exercise Lactate threshold Values Average individuals LT 40-60% of VO2 max Endurance trained LT>70% VO2 max. Guidelines of Improving CardioRespiratory endurance Four basic training variables F = frequency I = intensity T = time T = type (mode) Chapter 11 - Injury Prevention & Emergency Procedures 12 Guidelines of Improving Cardio-Respiratory endurance General Principles of Training Specificity— the body will adapt to the specific stress introduced. Overload--Manipulating any one of the four variables will result in overload. Reversibility—use it or lose it. 13 14 Importance of warm-up Increases blood flow to active muscles Increases blood flow to myocardium Increases the dissociation of oxyhemoglobin Earlier sweating May reduce abnormal heart rhythms Copyright © 2007 Lippincott Williams & Wilkins Importance of cool-down Prevents venous pooling Helps remove lactic acid Allows CV system to return to a resting state gradually. Cardiorespiratory adaptations from regular aerobic training Decreased RHR With consistent exercise (as few as three months of regular aerobic training), the interior dimensions of the ventricles increase, allowing them to hold more blood. The same cardiac output can be maintained at a lower HR due to the greater SV. 16 Cardiorespiratory adaptations from regular aerobic training Decreased relative working heart rate Since a given intensity requires a given amount of oxygen, HR at any given intensity will be lower due to an increased SV. A trained individual will have to work at higher intensities to achieve the same HR he or she achieved prior to physical training. 17 Cardiorespiratory adaptations from regular aerobic training Increased VO2max as SV increases VO2max (aerobic capacity) is the total capacity to take in, transport, and use oxygen during strenuous exercise. VO2max depends on two factors: The delivery of oxygen to the working muscle by the blood (cardiac output) The ability to extract oxygen at the capillaries and use it in the mitochondria 18 Cardiorespiratory adaptations from regular aerobic training Increased oxygen extraction This results in an improved ability to remain “aerobic” at higher intensities. Partly due to increased capillary density Partly due to increased mitochondrial density Partly due to an increased ability to create adenosine triphosphate (ATP) 19 Cardiorespiratory adaptations from regular aerobic training Increased fatty acid oxidation at any submaximal intensity More glycogen is stored in trained muscles and less lactic acid is produced Increased tolerance to lactic acid produced during exercise 20