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 O2/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 O2 ConsumptionStroke Volume–End Systolic Volume–End Diastolic Volume–Effected by position

Reduced in Cardiac Disease–Myocardial Infarction–Heart Failure

Muscle mass decreasedNeurologic dysfunction

Limits on O2 Consumption: Blood

Arterial Oxygen carrying capacity–Increased with exercise–Increased with increased Hemoglobin

Increased CaO2 - CvO2

–Mostly due to decreased CvO2

–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 CapacityBlood doped!

Tissue Blood Shunting with Exercise

 

Rest Blood Flow (mL)

% Blood Flow

Exercise Blood Flow (mL)

% Blood Flow

Muscle 1,000 20.0% 21,000 84.0%

Heart 200 4.0% 1,000 4.0%

Liver 1,350 27.0% 500 2.0%

Kidneys 1,100 22.0% 250 1.0%

Brain 700 14.0% 900 3.6%

Skin 300 6.0% 600 2.4%

Other 350 7.0% 750 3.0%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 BPBP 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 ExerciseDecreased VO2

Increased resting heart rate, blood pressureDecreased stroke volume at rest and with

exercise–Possibly due to decreased venous return

Have alterations in red blood cells, less red cellsDecreased 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 = 208 - 0.7(Age) (conventional technique underestimates the peak HR for age.

Example for 40 and 60 year old people– Standard Way: 220 - 40 = 180

220 - 60 = 160– Alternative Way: 208 - 0.7(40) = 180

208 - 0.7(60) = 166

Karvonen Technique

Calculate target heart rate based on intensity HRtarget = HRrest + %(HRmax - HRrest) Example: 30 year old woman to exercise at 80% of capacity after

testing– Resting HR = 75 bpm, Max HR on CPET 185 bpm– HRtarget= 75 + 0.80(185-75) = 163 bpm

Estimate method: HRtarget= 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 ExerciseDynamic–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)

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Basic Terminology Measurement of exercise capacity–Aerobic Training

VO2 – defined as LO2/minute or mlO2/kg/min MET – one metabolic equivalent - 3.5 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

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Basic Exercise for Health

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Warm-up and Cool-down GuidelinesWhat constitutes an effective warm-up? • Ideally the warm-up should involve low to

moderate intensity exercise that mimics thephysical activity to follow.

• Helps prevent musculoskeletal injuriesBenefits 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