Introduction to Exercise Physiology

1. Introduction to Exercise Physiology Hippocrates (460 -377 BC) • “Father of Preventative Medicine” Galen (131 - 201 AD) • most well-known & influential physician • “Laws of Health”

2. Galen Wrote about: • benefits of exercise • deleterious effects of sedentary living

3. Galen • Surgically repaired torn tendons & muscle • Recommended rehabilitation therapies • Recommended exercise regimes

4. Laws of Health (circa 140 AD) 1. Breathe fresh air 2. Eat proper foods 3. Drink the right beverages 4. Exercise 5. Get adequate sleep 6. Have a daily bowel movement 7. Control one’s emotions

5. Exercise Physiology History Harvard (late 19th century) • Department of Anatomy, Physiology, and Physical Training • B.S Degree (1891 - 1898)

6. This Course in Exercise Physiology Designed to heighten your awareness of: • General Health and Wellness • Preventative Medicine

7. Nutrition I Galen: “Eat proper foods” “Drink the right beverages”

8. Macronutrients • Carbohydrates (CHO) • Lipids • Proteins

9. Function of Macronutrients • Structural • Functional

10. Common Element • Carbon (C)

11. Carbohydrates (CHO) • Carbon (C) • Hydrogen (H) • Oxygen (O) • (CH2O)n

12. Monosaccharides • single sugar molecule • basic unit of CHO • categorized by # of carbons: - trioses - tetroses - pentoses - hexoses

13. Monosaccharides • glucose (dextrose) - blood sugar • fructose - fruit sugar • galactose - milk sugar

14. Glucose • main energy source • produced : - thru digestion of complex CHO - in liver via gluconeogenesis

15. Glucose absorbed in small intestine Cells Lipids Glycogen

16. Sucrose Fructose Galactose Lactose Glucose Maltose Oligosaccharides • disaccharides GLUCOSE

17. Plant Animal Polysaccharides Polysaccaharides

18. Starch Fiber Plant Polysaccharides Plant Polysaccaharides

19. Starch • storage form of CHO • complex CHO • most impt. dietary source of CHO • grain  bread, cereal, pasta

20. Fiber • Nonstarch polysaccharide • resistant to human digestion • make up structural components of plants • cellulose

21. Fiber • Linked w/ lower obesity, DM, intestinal disorders, HD, serum cholesterol • aid in gastrointestinal function (bulk): - scraping gut wall - dilute harmful chemicals -  transit time •  rate of digestion of CHO

22. Glycogen Liver Muscle Animal Polysaccharides Stored Glucose

23. Blood Glucose (5 grams) Muscle (325 grams) Liver (90 - 110 grams) CHO in the body 375 - 475 grams

24. Glycogen Utilization • directly by muscle • liver  blood glucose (glyogenolysis)  muscle

25. Glycogen Regulation •  blood glucose   insulin (pancreas[]) •  cellular uptake of blood glucose

26. Glycogen Regulation •  blood glucose   glucagon (pancreas[]) •  break-down of glycogen  blood glucose

27. Glycogen Regulation • very sensitive to changes in diet - depleted quickly - reserved quickly • upper limit = 15g /1 kg • excess is stored as lipids

28. CHO intake • 40 - 60% • sucrose (table sugar) vs. fructose (plant sugar) • fructose - fewer calories - does not stimulate insulin secretion - taken up by muscle w/o insulin  stable blood glucose

29. Role of CHO • energy source • preserve tissue proteins (structure) • CHO starvation  gluconeogenesis - protein  glucose - glycerol (lipids)  glucose

30. Role of CHO • allows for efficient lipid metabolism •  blood glucose  lipid mobilization  • incomplete lipid catabolism  ketone bodies (ketosis / acidosis) • seen w/: - CHO starvation - DM

31. Role of CHO • proper function of CNS • efficient nerve tissue metabolism

32. CHO and Exercise •  activity: -  use of muscle glycogen (anaerobic) -  release of glucose (liver)

33. CHO and Exercise • Intense exercise: - BG supplies 30% energy - muscle glycogen is majority • 1 hour of intense exercise 55%  glycogen • 2 hours 100%  • use of BG 

34. CHO and Exercise • Moderate exercise: - initially all glycogen - later 40-50% glycogen / lipid breakdown - later -  glycogen  lipid breakdown

35. CHO and Exercise • Continued exercise: - depletion of glycogen and BG  fatigue (“bonking”)

36. 4.0 Leg Glucose Uptake (mM/min) 1.0 10 40 Exercise Time (minutes) CHO and Exercise Heavy Exercise Moderate Exercise Mild Exercise Felig P, Wahren J. Fuel Homeostasis in exercise. N. Engl. J Med., 293: 1078, 1975.

37. Effect of Diet on Muscle Glycogen • diet low in CHO  quicker time to fatigue • high fat/low CHO diets   energy   endurance

38. 200 High CHO Time to exhaustion (minutes) Normal Diet Low CHO 50 1 4 Initial muscle glycogen (g/100 g muscle) Effect of Diet on Muscle Glycogen Bergstrom J. et. al. Diet, muscle glycogen and physical performance. Acta Physiol. Scand., 71: 140, 1967.

39. Lipids (Fats) • same elements as CHO • different linking and > H:O ratio

40. Simple Compound Derived Lipids Lipids

41. Simple Lipids • triglycerides - most plentiful • > 95% of body fat

42. Triglycerides • glycerol • fatty acids

43. Fatty Acids • saturated - holds many H atoms - animal products

44. Fatty Acids • unsaturated - usually plant sources - mono- canola, olive peanut - poly- safflower, sunflower, soybean, corn - hydrogenation - saturated-like (margarine, lard)

45. Compound Lipids • triglyceride + other chemicals • phospholipids (phosphate & nitrogenous base) - help control movement across cell membrane - structural integrity - blood clotting - myelin sheaths

46. Compound Lipids • Glycoproteins (CHO + N) • Lipoproteins (protein + triglycerides / phosolipids) - main form of lipid transport

47. Lipoproteins • Chylomicrons - transports lipid-soluble vitamins (A, D, E, & K) • HDL - 50% protein / 20% lipid / 20% cholesterol • LDL • VLDL - 95% lipid - transports triglycerides

48. HDL vs. LDL • LDL - deliver cholesterol to arterial walls - structural changes in walls • HDL - “reverse transport of cholesterol”  liver

49. HDL vs. LDL • Total cholesterol is not the issue • ratio of HDL to LDL •  HDL:LDL   risk of CAD •  exercise &  smoking   HDL

50. Derived Lipids • from simple & compound lipids • cholesterol - only in animals