Exercise: what the experts say

Darwin Deen, MD, MS

AECOM

Aug. 2002

This presentation and all of Dr. Deen’s PowerPoint presentations can be found at:

http://www.aecom.yu.edu/family/ugdeenpresents.htm

Healthy People 2010 lists Physical Activity as a Leading Health Indicator

Exercise and Health

In spite of the known health benefits of exercise (reduction in all-cause mortality, CVD, DM, colon CA, depression & anxiety), less than half of adolescents and young adults engage in regular vigorous exercise.

Exercise and Health

All-cause mortality is reduced up to 40% by an increase in weekly energy expenditure from 500 kcal to 2000 kcal.

In 1999 65% of adolescents engaged in the recommended amount of physical activity. The 2010 goal is 85%.

In 1997 only 15% of adults performed the recommended amount of physical activity. 40% reported no leisure-time physical activity. The 2010 goal for adults is 30%.

Healthy People 2010

What is “recommended”? For adolescents: vigorous physical activity

that promotes cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion.

For adults: regular (preferably daily), moderate physical activity for at least 30 minutes.

Exercise and Chronic Disease

Evidence-based Guidelines

Joint National Committee VI

Regular aerobic physical activity—adequate to achieve at least a moderate level of physical fitness— can enhance weight loss and functional health status and reduce the risk for cardiovascular disease and all-cause mortality.

When compared with their more active and fit peers, sedentary individuals with normal blood pressure have a 20- to 50-percent increased risk of developing hypertension.

Joint National Committee VI

Blood pressure can be lowered with moderately intense physical activity (40 to 60 percent of maximum oxygen consumption), such as 30 to 45 minutes of brisk walking most days of the week.

Most people can safely increase their level of physical activity without an extensive medical evaluation.

Patients with cardiac or other serious health problems need a more thorough evaluation, often including a cardiac stress test, and may need referral to a specialist or medically supervised exercise program.

NCEP - ATP III

Physical inactivity is a major risk factor for CHD. Increased emphasis on regular physical activity. Has clear benefits for the management of the

metabolic syndrome. The purposes of regular exercise are:

to promote energy balance to maintain healthy body weight,

to alleviate the metabolic syndrome, and to independently reduce baseline risk for CHD.

NIH Consensus Conference: Guidelines for the Evaluation and Treatment of Obesity

Evidence Statement:

Physical activity, i.e., aerobic exercise, in overweight and obese adults results in modest weight loss independent of the effect of caloric reduction through diet.

Evidence Category A.

NIH Consensus Conference: Guidelines for the Evaluation and Treatment of Obesity

Evidence Statement:

Physical activity in overweight and obese adults modestly reduces abdominal fat.

Evidence Category B.

NIH Consensus Conference: Guidelines for the Evaluation and Treatment of Obesity

Evidence Statement:

Physical activity in overweight and obese adults increases cardio-respiratory fitness independent of weight loss.

Evidence Category A.

USPSTF:Guide to Clinical Preventive Services

Being sedentary doubles CVD risk and getting active results in a 41% decrease in mortality (smoking cessation causes a 44% reduction).

The risk of HT is also half in those who exercise and the risk of weight gain leading to obesity is less.

There is a 6% decrease in the risk of Type II DM for each 500 cal expended per week.

Exercise is associated with less osteoporosis risk and improved mental health.

Moderate physical activity is that which can be sustained for an hour. Vigorous physical activity results in exhaustion after 30 minutes.

Metabolic Equivalents

Caloric expenditure during exercise is expressed as METs (multiples of REE).

Shooting baskets only 4.5.

Baseball & recreational football ~5.

A 70 kg person would burn ~6 kcal/min in a 5 MET activity.

Biking 4-10 METS*

Walking 3.5-6

Running 8-13

Basketball ~8

Swimming ~8

Tennis ~8

ranges depend upon speed

Examples of Sedentary and Active Energy Expendituresfor Common Activities

SEDENTARY kcal ACTIVE kcal

Using remote control device

to change television channel

<1 Getting up and

changing channel

3

Reclining for 30 min

of phone calls

4 Standing for 3 10-min

phone calls

20

Using garage door opener <1 Raising garage door 2x/d 2-3

Hiring someone to

clean and iron

0 Ironing and vacuuming

each for 30 min

152

Waiting 30 min

for pizza delivery

15 Cooking for 30 min 25

Examples of Sedentary and Active Energy Expendituresfor Common Activities

SEDENTARY kcal ACTIVE kcal

Buying pre-sliced vegetables 0 Washing, slicing, chopping vegetables for 15 min

10-13

Using a leaf blower

for 30 min

100 Raking leaves for 30 min 150

Using a lawn service 0 Gardening and mowing

each for 30 min/wk

360

Using car wash 1x/mo 18 Washing and waxing

car, 1 h/mo

300

Letting dog out

the back door

2 Walking dog for 30 min 125

Examples of Sedentary and Active Energy Expendituresfor Common Activities

SEDENTARY kcal ACTIVE kcal

Riding escalator 3x 2 Climbing 1 flight of stairs, 3x/wk in mall

15

Shopping online 1 h 30 Shopping at mall,

walking 1 h

145-240

Sitting in car at

drive-in window, 30 min

15 Parking and walking inside, 3x/wk, total of 30 min

70

Paying at the pump 0.6 Walking into station

to pay, 1x/wk

5

Sitting and listening

to lecture, 60 min

30 Giving lecture 70

Anaerobic vs. Aerobic

Anaerobic

Glucose -> Pyruvate

Aerobic

Pyruvate -> CO2 + H2O

Muscle Metabolism

Lipids are the preferred fuel for muscle cells at up to 25% of maximum work.

At 65%, glycogen is burned preferentially. At high intensities, the longer the duration

of exercise, the greater proportion of fat is metabolized.

With training, muscle burns relatively more fat and less CHO.

Distribution of carbohydrate energy in an average 80-kg person

Muscle Glycogen

Liver Glycogen

Plasma Glucose

Distribution of fat energy in an average 80-kg person

Adipose Tissue

Intramuscular TG

Plasma TG

Plasma FFA

The Exercise Prescription

Type of exercise Resistance exercise to improve strength Aerobic training to improve aerobic capacity

Frequency: 3-5 days/week Intensity: 60-85% of maximal oxygen

consumption (maximal heart rate =220-age)

Duration: 20-60 min

Physical Activity Counseling

Little or no desire to engage in additional physical activity

“I know I should exercise but right now I have too much going on to even think about it.”

Explain the benefits, specific to the individual.

Encourage patient to express their reservations.

Precontemplation

Physical Activity Counseling

“I’ve never been very athletic, and at this stage of my life, it does not seem like a good time to begin.”

Define how much activity they need for health benefits.

Give clear advice r.e. how important it is.

Precontemplation

Physical Activity Counseling

Patients understand the benefits but lack the skills, support, or confidence to initiate action.

Practice active and reflective listening.

Use information provided by the patient to motivate.

Contemplation

Physical Activity Counseling

“I want to, I just haven’t gotten started.”

Explain how the patient can work exercise into their daily routine.

Help the patient develop a specific plan with realistic goals.

Contemplation