Rehabilitation Medicine Cardiopulmonary Exercise in the Aging Adult Matthew N. Bartels, MD, MPH Professor and Chairman of Rehabilitation Medicine Albert Einstein College of Medicine Chairman, Department of Rehabilitation Medicine Montefiore Medical Center

Declarations/Disclosures  Unfortunately no Conflicts of Interest –Working on that……  No off label uses of medications or devices

Objectives  Effects of aging on cardiopulmonary exercise capacity  Review the basics of exercise physiology  Beneficial effects of aerobic and strengthening exercise on cardiovascular physiology in older individuals

Bad News and Good News with Aging  Bad News –Capacity declines as you age  Good News –You can do something about it –Fatigue and immobility are not inevitable parts of aging –Fitness isn’t all that hard to achieve

The Bad News About Aerobic Exercise with Aging  Bad News 1: Muscle function changes with age –Strength decreases due to loss of muscle mass. –Fiber type switching to type II x –Increased fibrous tissue in muscle

Bad News 2: cardiovascular function change with age –Maximum heart rate decreases with age (MHR = 220 – age) –Resting cardiac output declines about 1%/year during adulthood –Coronary artery disease is more common –Blood flow during exercise is less –Maximum exercise declines gradually with age

Bad News 3: Pulmonary Function Changes with Age  Lung capacity declines  Chest wall is stiffer (less compliance)  Decreased oxygen absorbtion (lower DLCO)  Breathing becomes less efficient with age  Loss of lung with aging (1% per year)

Bad News 4: Aging Alters Body Composition Body Composition  Increased Fatty Tissue  Decreased Lean Mass Stature  We grow shorter as we get older by about one-half inch per decade after age 30.

Bad News 5: Multiple factors may explain the changes in functional capacities with age  True aging phenomena  Unrecognized disease processes  Disuse phenomena  Deconditioning  Medications

Assessment of Demands of Exercise Activities  Usually used for dynamic exercise  Typically described in terms of metabolic equivalents –1 MET = 3.5 ml O 2 /Kg weight/min  Use of standardized MET tables can help assess independence AND GOALS

Oxygen Consumption with Exercise

Relationship of Dynamic Exercise and Oxygen Uptake Heart Disease

Limits on O 2 Consumption  Stroke Volume –End Systolic Volume –End Diastolic Volume –Effected by position  Reduced in Cardiac Disease –Myocardial Infarction –Heart Failure  Muscle mass decreased  Neurologic dysfunction

Limits on O 2 Consumption: Blood  Arterial Oxygen carrying capacity –Increased with exercise –Increased with increased Hemoglobin  Increased C a O 2 - C v O 2 –Mostly due to decreased C v O 2 –Increased Peripheral extraction  Shunting of increased Output to active tissues  This is where blood doping in professional sports comes in! –Autotransfusion, Epo, etc.

Oxygen Carrying Capacity Blood doped!

Tissue Blood Shunting with Exercise Rest Blood Flow (mL) % Blood Flow Exercise Blood Flow (mL) % Blood Flow Muscle 1, %21, % Heart %1,0004.0% Liver 1, %5002.0% Kidneys 1, %2501.0% Brain %9003.6% Skin %6002.4% Other %7503.0% Total Blood Flow 5,000 25,000

Effects of Dynamic Exercise on Blood Pressure  Minimal change in Diastolic BP –May actually drop a little  Marked Rise in a linear fashion in SBP –Does not usually rise above 200 mmHg  Moderate rise in Mean BP  BP increase due to increased CO, not increased peripheral resistance.  Effects are about 10% higher for arm exercise than leg exercise.

Effects of Dynamic Exercise on Blood Pressure

Response to Isometric Exercise  This is not safe type of exercise for Cardiac Patients!  Lower metabolic demand for a given activity  Marked increases in SBP, DBP, MBP –Can easily exceed 220/110 mmHg (SBP/DBP)  Marked heart rate increase –Out of proportion to the metabolic demand of the activity  SV lowered with activity, rebounds with relaxation  Cardiovascular steady state not achieved  Muscle blood flow decreased during >40% contraction, increased at <30% contraction

Blood Pressure Responses to Isometric Exercise

Effects of Inactivity on Exercise  Decreased VO 2  Increased resting heart rate, blood pressure  Decreased stroke volume at rest and with exercise –Possibly due to decreased venous return  Have alterations in red blood cells, less red cells  Decreased responsiveness in muscle vascular beds – higher blood pressure!

Inactivity and Exercise Capacity

Good News 1: There are Benefits to Aerobic Exercise  Improved sense of well being  Weight control  Decreased fatigue  Improved immunity  Decreased bone/lean body mass loss  Decreased cardiac disease  Decreased decline in function

Good News 2: These benefits of exercise come about in many ways  Improved efficiency –Increased cardiac function –Improved circulation –Improved muscle function –Improved neural control of function –Increased lean body mass –Improved basal metabolic function

Good News 3: Improved Heart Function  Improved cardiac output –Increased stroke volume  Decreased resting heart rate –Decreased anginal symptoms –Decreased work of the heart  Decreased systemic blood pressure –Less resistance for cardiac work

Good News 4: Improved Circulation  Decreased arterial resistance  Decreased blood pressure  Improved capillary function –Decreased diastolic blood pressure –Improved delivery of oxygen to the peripheral tissues  Improved muscle tone in the blood vessel walls

Good News 5: Improved Muscle Function  Improved muscular circulation  Improved capacity to aerobically metabolize and perform work  Increased mitochondria (muscle power generation)  Increased muscle fiber density

Good News 6: Increased Lean Body Mass  Increase in muscle tissue  Decrease in fatty tissue  Improved metabolism –Increase use of fat –Decreased storage of fat  Helps with weight maintenance  Decreased appetite –Moderate exercise decreases appetite

SURPRISE! Aerobic Exercise is Reasonably Easy to Do  Even Moderate daily activities are helpful –Brisk walking –Gardening –Yard work –Housework –Climbing stairs –Active recreational pursuits

Principles of aerobic training for a healthy older adult  Mode: –Aerobic activity  Intensity: –An intensity of 55 to 90 percent of maximal heart rate or 40 to 85 percent of maximum heart rate reserve  Duration: –A duration of 20 to 60 minutes a session (or in 10-minute bouts accumulated throughout the day)  Frequency: –A frequency of three to five days per week

Estimation of Maximum Heart Rate  Usual Method: Max HR = 220-Age  Alternative method (for older ages): –Max HR = (Age) (conventional technique underestimates the peak HR for age.  Example for 40 and 60 year old people –Standard Way: = 180  = 160 –Alternative Way: (40) = 180  (60) = 166

Karvonen Technique  Calculate target heart rate based on intensity  HR target = HR rest + %(HR max - HR rest )  Example: 30 year old woman to exercise at 80% of capacity after testing –Resting HR = 75 bpm, Max HR on CPET 185 bpm –HR target = (185-75) = 163 bpm  Estimate method: HR target = 0.80(220-30) = 152 bpm  Estimated HR targets usually lower and less accurate. But preserves safety in situation with no testing.

Caution 1: Recommendations for Developing and Maintaining Fitness  Use large muscle groups  Continuous, rhythmical, aerobic activities  Use heart rate guidelines  Use Warm-up and Cool-down  Assess cardiac risk –Simple history => family history –Unexplained dyspnea  Orthopedic risks

Types of Exercise  Dynamic –Aerobic - Cardiac –Conditioning - Cardiac  Static –Anaerobic - Non Cardiac –Strengthening - Non Cardiac

Remember Basic Physiology!  Endurance activity requires more aerobic fibers –This is predominantly Type 1 fibers  Sustain activity for hours, but slow twitch speed and small fiber size  Short burst activity requires more anaerobic fibers –These are predominantly Type 2 fibers subdivided into:  2a moderately fast – long term anaerobic (<30 min)  2x fast – intermediate short term aerobic(<5 min)  2b very fast – short term aerobic (<1 min) 35

Basic Terminology  Measurement of exercise capacity –Aerobic Training  VO2 – defined as LO2/minute or mlO2/kg/min  MET – one metabolic equivalent mlO2/kg/min  Wattage – Resistance on an ergometer – this is power output  Heart rate – Used to determine the level of intensity once power at a given heart rate established  RPE – can guide exercise once power rates determined –Resistance Training  Maximum Voluntary contraction – one rep max 36

Basic Exercise for Health 37

Warm-up and Cool-down Guidelines What constitutes an effective warm-up? Ideally the warm-up should involve low to moderate intensity exercise that mimics the physical activity to follow. Helps prevent musculoskeletal injuries Benefits of cooling down after low to moderate activity  Helps to clear lactic acid from the blood  Prevents blood pooling in the lower extremities, which can cause dizziness/vasovagal syncope  Helps maintain increased muscle and connective tissue temperature, increasing flexibility

Conclusion  Moderate aerobic exercise is very beneficial and safe in most individuals  Even (especially) individuals with cardiac, pulmonary, or peripheral vascular disease will benefit.  After the age of 40, consider if there are risks prior to high intensity exercise, moderate is always safe  Qualified supervision in disease states –May benefit from specific programs