The Importance of Exercise

1. The Importance of Exercise Dr Reed A Berger

2. Human beings have evolved with movement as a necessity for survival e.g. to obtain food, to escape predators thus, numerous systems in the body are sensitive to movement. Today, why do people exercise? Athletic/Artistic Performance Physical appearance How can we increase exercise for health reasons? education - require PE for schools? support - physicians, family research Health

3. Benefits of Exercise • Increased strength and muscular endurance • Increased BMD—osteoporosis • Aging—decreased falls, increased independence, increased ADL • Increased BMR—LBM • Appearance, self esteem

4. Technology—fewer demands placed on musculoskeletal and CV systems • 2-3 generations ago—manual labor • Stairs, elevators, cars • Recreation—playing ball, jumping, hide-n-seek vs. video games, internet • Convenience and fast foods

5. Automation—decreased muscular demands • Body adapts—increased fast, weaker • Scheduled exercise used to not be needed with manual labor • Today, have to “give back” the leisure time gained thru technology and purposely stress the muscular system

6. I. Basics of Exercise Physiology Exercise is a complex molecular, cellular and systemic physiological stimulus With every single bout of exercise, skeletal muscles, heart, brain, vascular tissue, bone, liver, etc. experience some form of environmental “stress”. The type and magnitude of an adaptation or response to exercise thus results from a sum total of all these contributing factors. Some examples include: • mechanical, stress/strain • - temperature • - pH • - redox state • - free radical production • - hormones/growth factors • - calcium

7. Specificity of Exercise: Adaptations that occur in response to training are specific to the nature of the training stimulus Cardiovascular fitness: requires that the person train in a manner that challenges heart rate, cardiac output, capillarity … with the underlying change being improved oxygen delivery to working tissues Muscular strength: requires that the person train in a manner that challenges the recruitment and force output of specific muscle groups … with the underlying change being increased muscle mass. The corollary to this is that training for endurance will not augment strength or vice versa.

8. Cardiovascular fitness - endurance type activities: fuel challenging large muscle mass repetitive lower intensity walking, running, swimming, cycling Muscular strength: high resistance, high force output focus on muscle groups not on systemic “exercise” e.g. knee extensors vs. flexors Can a type of exercise be both strength and endurance? yes BUT the effectiveness of any one form of activity to elicit a specific adaptation is dependent on the endurance/strength starting state of the individual.

9. Basic Principles of Exercise Training Frequency - how often is the exercise performed each week? For cardiovascular training effects 3-4x per week is suggested Intensity - the exercise must be performed at a level that challenges the cell/tissue/system for adaptations to occur. Totally dependent on starting state. Lower the starting fitness level the lower the starting intensity. Must build to continue adaptations. Most important variable in training regimen for most. Duration - length of each training session. For cardiovascular Adaptations it is suggested to start at 30 minutes/session MORE IS NOT NECESSARILY BETTER! overtraining/system failure

10. Known adaptations to endurance exercise Skeletal Muscle Ý mitochondria Ý capillary density Ý oxidative enzymes • Heart • Ý heart volume • Ý max stroke volume • Ý max cardiac output • resting heart rate • Û blood pressure Brain (very new studies) Ý neurogenesis Ý protection from seizures, injury Bone Ý density? Type of exercise

11. What is Maximum Oxygen Uptake? VO2 Max Maximal amount of oxygen consumption per minute The more muscle used the higher the oxygen use Predictor of performance? Correlates with changes in cardiac output Training will result in an increase cardiac indices (CO, SV) skeletal muscle contribution (mito) ventilatory contribution?

12. Known adaptations to resistance exercise Brain/Neural Ý improved recruitment Skeletal Muscle Ý Fiber size Ý Mitochondria? Bone Ý density

13. Role of exercise in weight and/or body fat control Calories in vs. Calories out Exercise can increase caloric expenditure Exercise can spare loss of lean body mass during times of caloric deficit Increases in lean body mass will increase basal metabolic rate BUT …. 10lbs of lean body mass will lead to about 70-80kcal/day ALL forms of exercise will burn fat, even at Max VO2 Amount of fat burned during exercise is NOT important. Total calories used during exercise IS important For patients/clients, pick an exercise/activity modality that they will do and do regularly. Type of exercise less important a

14. Exercise prescription • To treat various diseases • Primary prevention—PE class • Clinically—discuss exercise • Work—corporate wellness • End of college, athletic endeavors—need to have scheduled exercise • 60 min daily

15. Aerobic and resistance • Convenient • Traveling • Pedometer • Minutes per day • Intensity, duration, frequency (need to vary)

16. Routine exercise • Improves tissue oxygen uptake • HDL • LDL • TG • BP • Glycemic control

17. Decreased risk of CA • Endometrial • Breast • Colon • prostate

18. Cognitive benefits • Better adjusted • Cognitive tests • Decreased CV response to stress • Anxiety • Depression • People who were active and became inactive were 1.5x more likely to become depressed • CAD and depression

19. Cognitive cont’d • Improves self confidence • Self esteem • Decrease CV and neurohormonal response to stress • Short bouts of exercise—cognitive improvement

20. compliance • Long term adherence to exercise • Decrease with age, minorities, females, disabled, chronic dz • Exercise program—50% cont for >6 mo

21. Types of exercise • Occupational, recreational, sports • Aerobic • Anaerobic—sprint • Isometric—wts

22. Resistance training • Resistance to contracting muscles to stimulate them for increased strength • Injury risk—decreased • Lean tissue and aging • Heart conditions—don’t strain or hold breath

23. How to make exercise a lifetime activity • Pick activity that is enjoyable and uses most muscles • Vary duration, intensity • Group classes • Music • Walk the dog! • Set goals—health, appearance, cholesterol

24. Elderly • Joint flexibility • Muscle strength • LBM • Balance • Prevention of injury

25. Pulmonary dz • Low workloads, short duration • Frequent intervals • Supplemental O2

26. Maternity • Maternal • Increased CV fxn • Decreased wt gain and fluid • Mental state • Labor • Recovery • fitness

27. maternity • Fetus • Decreased fat • Improved stress • Neurobehavioral maturation

28. osteoporosis • BMD • Muscle—balance, falls, fracture • Works with estrogen, diet • Wt bearing

29. CAD • Primary and secondary prevention • Increased CV functional capacity and decreased myocardial O2 demand • Lipids, DM, obesity • BP—8-10 mmHg • Inactivity is independent risk factor for CAD • Sedentary have greatest CVD mortality

30. III. Application for Health Care Obesity Type II Diabetes - Obesity is reaching "epidemic proportions” in the United States - could soon cause as much preventable disease and death as cigarette smoking. For the vast majority of individuals, overweight and obesity result from excess calorie consumption and/or inadequate physical activity. Unhealthy dietary habits and sedentary behavior together account for approximately 300,000 deaths every year.

31. Exercise and Type II Diabetes Position statement ACSM About 10.3 million diagnosed cases and about 5.4 million undiagnosed Accounts for 90-95% of all cases of diabetes Characterized by insulin resistance and moderate insulin deficiency Skeletal muscle: site of about 80-90% of glucose uptake insulin and contraction act INDEPENDENTLY to increase GLUT4 translocation and glucose uptake. Ideal target for exercise and/or pharmacological therapies

32. Acute Effects of Physical Activity Glucose Levels Most obese Type II diabetics experience decreases in blood glucose following mild-moderate exercise magnitude of effect is dependent on duration and intensity blood glucose increases with short term high intensity exercise

33. Insulin resistance Insulin resistant individuals have 35-40% reduction in insulin mediated glucose uptake Low to moderate intensity exercise improves insulin sensitivity High intensity exercise variable response Transient effect (about 72 hrs) so requires regular activity not really the “trained state”

34. Physiological Benefits of Exercise for those with Type II Diabetes Lower resting heart rate Lower submaximal exercise heart rate Increased stroke volume Increased cardiac output Enhanced oxygen extraction Lower resting BP Lower exercise BP Influence lipid profile

35. Psychological Benefits of Exercise Reduced stress response to psychosocial stimuli Lessened sympathetic nervous system activation to cognitive stress Reductions in depression Improved self-esteem Reduction in emotional perturbations to stress Contribute to sustained behavioral changes and adherence

36. Exercise and Chronic Diseases Booth et al., 2000 Cardiovascular Disease Type II Diabetes Obesity Obesity related diseases Aging While all these diseases have some contribution from genetic the rapid increases in the last 20+ years are due to environmental factors. Sedentary living is responsible for about 34% of deaths due to coronary heart disease, colon cancer and Type II diabetes CDC has concluded that “physical inactivity is one of the major underlying causes of premature mortality in the US”

37. Take home message • 1. Consider exercise/physical activity for both • disease prevention as well as treatment • 2. When considering exercise think movement • or activity not athletic performance • 3. Consider the importance of exercise • for children. Growing evidence for mental as well as • physical development. Educate for healthy lifestyle • Good resource for exercise and health information • American College of Sports Medicine www.acsm.org