EPOC during High and Low-Intensity Exercise

EPOC during High-Intensity, Long-Duration Exercise

O2 UPTAKE vs POWER OUTPUT (1996)

Motor Unit Recruitment Patterns and the Slow Component of VO2

Static Lung Volumes

TV Response to Exercise TV plateaus at approximately 60% FVC (70-80% VO2max)

Room Air PO2 = 159 mmHg PCO2 = 0 mmHg Trachea PO2 = 149 mmHg PCO2 = 0 mmHg Alveoli PO2 = 105 mmHg PCO2 = 40 mmHg Venous Blood PO2 = 40 mmHg PCO2 = 46 mmHg Arterial Blood PO2 = 100 mmHg PCO2 = 40 mmHg Muscle PO2 = 40 mmHg PCO2 = 46 mmHg

How is Oxygen Transported in the Blood? In solution (3%) Attached to Hb 1.34 ml O2/gm Hb Arterial O2 content = 0.3 ml 02/dl blood + (1.34 O2/Hb x 15 g Hb/dl) = 20.4 ml 02/dl blood Diphosphoglycerate mutase on RBC, which converts 1,3 DPG into 2,3 DPG. 2,3 DPG levels increase acutely during exercise and altitude.

How is CO2 Transported in the Blood?

RESPIRATORY REGULATION

Ventilation during Exercise

VO2, VE above LT

Cardiac Output at Rest = 5 L/min Heart: 4% 200 ml Liver: 27% 1350 ml Kidneys: 22% 1100 ml Brain: 14% 700 ml Skin: 6% 300 ml Muscles: 20% 1000 ml Other: 7% 350 ml

Cardiac output during moderate exercise = 17.6 L/min Liver: 3% 600 ml Heart: 4% 750 ml Other: 3% 500 ml Kidneys: 3% 600 ml Muscles: 71% 12,500 ml Skin: 12% 1900 ml Brain: 4% 750 ml

Venous Return Smooth muscle bands Increased cardiac output means increased venous return!!!

CHANGES IN HR, SV, AND Q . Smallest increase in SV is during supine exercise Highest max SV seen for swimming followed by running, then cycling Trained cyclists have similar values to TM

CIRCULATORY RESPONSES

Blood Flow Shunting to Working Muscle Arteries in other tissue Arteries in skeletal muscle Sympathetic Nervous System Stimulation: Catecholamines stimulate alpha receptors to constrict, and B2 receptors to vasodilate. Stimulate NO production via endothelial cells Adenosine is THE MOST IMPORTANT metabolic by-product that increases dilation During high intensity exercise, vasodilation may decrease BP to the extent that baroreceptors and renin will cause a vasoconstriction Vasoconstriction Increased Epinephrine -causes vasodilation in skeletal and cardiac muscle, vasoconstriction in other tissue Metabolic by-products: K+, heat, H+, adenosine, lactate, CO2

CHANGES IN ARTERIOVENOUS OXYGEN