Chapter 01​ ​ Benefits and Risks​ Associated With Physical​ Activity

For Exam This Thursday

Physical activity (PA):

Any bodily movement produced by the contraction of skeletal muscles that results in a substantial increase in caloric requirements over resting energy expenditure.

Exercise:

A type of PA consisting of planned, structured, and repetitive bodily movement done to improve and/or maintain one or more components of physical fitness.

Physical fitness:

A set of attributes or characteristics individuals have or achieve that relate to their ability to perform PA and activities of daily living.

Health-Related Physical Fitness Components: Cardiorespiratory endurance

the ability of the circulatory and respiratory system to supply oxygen during sustained

physical activity

Health-Related Physical Fitness Components: Body composition

the relative amounts of muscle, fat, bone, and other vital parts of the body

Health-Related Physical Fitness Components: Muscular strength

the ability of muscle to exert force

Health-Related Physical Fitness Components: Muscular endurance

the ability of muscle to continue to perform without fatigue

Health-Related Physical Fitness Components: Flexibility

the range of motion available at a joint

Skill-Related Physical Fitness Components: Agility

the ability to change the position of the body in space with speed and accuracy

Skill-Related Physical Fitness Components: Coordination

the ability to use the senses, such as sight and hearing, together with body parts in performing tasks smoothly and accurately.

Skill-Related Physical Fitness Components: Balance

the maintenance of equilibrium while stationary or moving

Skill-Related Physical Fitness Components: Power

the ability or rate at which one can perform work

Skill-Related Physical Fitness Components: Reaction time

the time elapsed between stimulation and the beginning of the reaction to it

Skill-Related Physical Fitness Components: Speed

the ability to perform a movement within a short period of time

Light Intensity

(1.6-2.9 METs)

Moderate Intensity

(3.0–5.9 METs)

Vigorous Intensity

(> 6 METS)

Light Intensity: Walking

Walking slowly around home, store, or office = 2.0a

Light Intensity: Household and occupation

Standing performing light work, such as making bed, washing dishes, ironing, preparing food, or store clerk = 2.0–2.5

Light Intensity: Leisure time and sports

All the above

Moderate Intensity: Walking

• Walking 3.0 mi · h−1=3.0a

• Walking at very brisk pace (4 mi · h−1) = 5.0

Moderate Intensity: Household and occupation

• Cleaning, heavy washing windows, car, clean garage = 3.0

• Sweeping floors or carpet, vacuuming, mopping = 3.0–3.5

• Mowing lawn, walk power mower = 5.5

Moderate Intensity: Leisure time and sports

• Table tennis = 4.0

• Tennis doubles = 5.0

• Volleyball — noncompetitive = 3.0–4.0

Vigorous Intensity: Walking, jogging, and running

• Running at 7 mi · h−1= 11.5

• Walking at very, very brisk pace (4.5 mi · h−1) = 6.3a

• Jogging at 6 mi · h−1 = 10.0a

Vigorous Intensity: Household and occupation

• Shoveling, digging ditches = 8.5

• Carrying heavy loads, such as

  bricks = 7.5

Vigorous Intensity: Leisure time and sports

• Tennis singles = 8.0

• Basketball game = 8.0

• Volleyball — competitive at gym or beach = 8.0

What are the amount and intensity of PA needed to improve aerobic health, lower susceptibility to disease (morbidity), and decrease premature mortality?

• All healthy adults aged 18–65 years

  • should participate in moderate-intensity aerobic PA for a minimum of 30 minutes on 5 d · wk−1 or vigorous-intensity aerobic activity for a minimum of 20 minutes on 3 d · wk−1.

  • Combinations of moderate- and vigorous-intensity exercise can be performed to meet this recommendation.

  • Moderate-intensity aerobic activity can be accumulated to total 30 minutes by performing bouts, each lasting ≥10

    minutes.

  • Every adult should perform activities that maintain or increase muscular strength and endurance for a minimum of 2 d ·

    wk−1.

    
    

Two important conclusions from the Physical Activity Guidelines Advisory Committee Report that influenced the development of the PA recommendations are the following:

• Important health benefits can be obtained by performing a moderate amount of PA on most, if not all, days of the week.​

• Additional health benefits result from greater amounts of PA. Individuals who maintain a regular program of PA that is longer in duration, of greater intensity, or both are likely to derive greater benefit than those who engage in lesser amounts.

The Primary Physical Activity Recommendations for Adults From the Physical Activity Guidelines for​

• Adults should move more and sit less throughout the day. Some physical activity is better than none. Adults who sit lessand do any amount of moderate-to-vigorous physical activity gain some health benefits.

• For substantial health benefits, adults should do at least 150–300 min · wk−1 of moderate-intensity or 75–150 min · wk−1of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity. Preferably, aerobic activity should be spread throughout the week.

• Additional health benefits are gained by engaging in physical activity beyond the equivalent of 300 minutes of moderate￾intensity physical activity a week. Adults should also do muscle strengthening activities of moderate or greater intensity and that involve all major muscle groups on 2 or more d · wk−1, as these activities provide additional health benefits.

Physical inactivity:

a global pandemic that has been identified as one of the four leading contributors to premature mortality.​

Public Health Perspective for Current Recommendations:

• Globally, 31.1% of adults are physically inactive.​​

In the United States:​ _______ % of adults meet aerobic activity guidelines.​

50.9%

In the United States:​ _______ % meet muscle strengthening guidelines.

30.4%

In the United States:​ _______ % meet both the aerobic and muscle strengthening guidelines.

20.5%

Sedentary Behavior and Health​

• Prolonged periods of sitting or sedentary behavior are associated with deleterious health consequences independent of PA levels.​

• Self-report NHANES data indicate 5.57.1 h · d−1 of sitting time.​

• Objectively measured accelerometer data indicate 7.78.0 h · d−1 sitting time.​

• Regardless, high levels of sedentary behavior can be detrimental to one’s health.​

Health Benefits of Regular PA and Exercise​

Evidence to support the inverse relationship between regular PA and/or exercise and premature mortality, CVD/CAD, hypertension, stroke, osteoporosis, T2DM, metabolic syndrome (Metsyn), obesity, certain cancers, depression, functional health, falls, and cognitive function​

Improvement in Cardiovascular and Respiratory Function

• Increased maximal oxygen uptake resulting from both central and peripheral adaptations

• Decreased minute ventilation at a given absolute submaximal intensity

• Decreased myocardial oxygen cost for a given absolute submaximal intensity

• Decreased heart rate and blood pressure at a given submaximal intensity

• Increased capillary density in skeletal muscle

• Increased exercise threshold for the accumulation of lactate in the blood

• Increased exercise threshold for the onset of disease signs or symptoms (e.g., angina pectoris, ischemic ST-segment depression, claudication)

Reduction in Cardiovascular Disease Risk Factors

• Reduced resting systolic/diastolic pressure

• Increased serum high-density lipoprotein cholesterol and decreased serum triglycerides

• Reduced total body fat and intra-abdominal fat

• Reduced insulin needs; improved glucose tolerance

• Reduced blood platelet adhesiveness and aggregation

• Reduced inflammation

Decreased Morbidity and Mortality

• Primary prevention (i.e., interventions to prevent the initial occurrence).

• Higher activity and/or fitness levels are associated with lower death rates from CAD.

• Higher activity and/or fitness levels are associated with lower incidence rates for CVD; CAD; stroke; Type 2 diabetes mellitus; metabolic syndrome; osteoporotic fractures; cancer of the bladder, breast, colon, endometrium, and lung; and gallbladder disease.

• Secondary prevention (i.e., interventions after a cardiac event to prevent another).

• Based on meta-analyses (i.e., pooled data across studies), cardiovascular and all-cause mortality are reduced in patients with post-MI who participate in cardiac rehabilitation exercise training, especially as a component of multifactorial risk factor reduction.

Other Benefits

• Decreased anxiety and depression

• Improved cognitive function

• Enhanced physical function and independent living in older individuals

• Enhanced feelings of well-being

• Enhanced quality of life

• Improved sleep quality and efficiency

• Enhanced performance of work, recreational, and sport activities

• Reduced risk of falls and injuries from falls in older individuals

• Prevention or mitigation of functional limitations in older adults

• Effective therapy for many chronic diseases in older adults

Health Benefits of Improving Muscular Fitness

• The health benefits of enhancing muscular fitness (i.e., the functional parameters of muscle strength, endurance, and power) are well established.​

• Higher levels of muscular strength are associated with a significantly better cardiometabolic risk factor profile, lower risk of all-cause mortality, fewer CVD events, lower risk of developing physical function limitations, and lower risk for nonfatal disease.

Risks Associated With PA and Exercise ​

Although the benefits of regular PA are well established, participation in exercise is associated with an increased risk for musculoskeletal injury (MSI) and cardiovascular complications such as sudden cardiac death (SCD) and acute myocardial infarction (AMI).​

_______ is the most common exercise-related complication and is often associated with exercise intensity, the nature of the activity, preexisting conditions, and musculoskeletal anomalies.​

MSI

_______ and ________ are associated with vigorous intensity and are much less common than MSI but may lead to long-term morbidity and mortality.​

SCD and AMI

Sudden Cardiac Death Among Young Individuals: Men

One per ~62,000 men​

Sudden Cardiac Death Among Young Individuals: Women

One per ~523,000 women​

Death rates also appear to be higher in ____________ male athletes and basketball players specifically.​

African American

_______ is related to the absence or presence of occult CVD, exercise intensity, age, and PA.​​

Risk

Exercise-Related Cardiac Events in Adults​

• In general, exercise does not provoke cardiovascular events in healthy individuals with normal cardiovascular systems.​

• ​The Physicians’ Health Study and Nurses’ Health Study suggest that SCD(sudden cardiac death) occurs every 1.5 million episodes of vigorous physical exertion in men and every 36.5 million hours of moderate-to-vigorous exertion in women.​

• The Onset Study showed that the risk of AMI (acute myocardial infraction) during or immediately following vigorous-intensity exercise was 50 times higher for the habitually sedentary compared to individuals who exercised vigorously for 1-hour sessions >5 d  wk−1.​

Habitual Frequency of Vigorous PA

Acute Myocardialinfraction risk increasesduring and immediatelyfollowing vigorous activityin both sedentary andactive individuals.​

Exercise Testing and the Risk of Cardiac Events​

• As with vigorous-intensity exercise, the risk of cardiac events during exercise testing varies directly with the prevalence of diagnosed or occult CVD in the study population.​

• These data indicate that in a mixed population, the risk of exercise testing is low, with approximately six cardiac events per 10,000 symptom-limited maximum tests.​

• People who have cardiovascular disease have a greater risk on cardiac events.

Risks of Cardiac Events During Cardiac Rehabilitation​

• In one survey, there was one nonfatal complication per 34,673 patient-hours and one fatal cardiovascular complication per 116,402 patient-hours of cardiac rehabilitation.​

• More recent studies have found a lower rate, one cardiac arrest per 116,906 patient-hours, one MI per 219,970 patient-hours, one fatality per 752,365 patient-hours, and one major complication per 81,670 patient-hours.​

• The mortality rate appears to be 6 times higher when individuals exercised in facilities without the ability to successfully manage cardiac arrest; however, a review of home-based cardiac rehab programs found no increase in cardiovascular complications compared to formal center-based exercise programs.​

Prevention of Exercise-Related Cardiac Events

• Health care professionals should know the pathologic conditions associated with exercise-related events so that physically active children and adults can be appropriately evaluated.​

• Physically active individuals should know the nature of cardiac prodromal symptoms and seek prompt medical care if such symptoms develop.​

• High school and college athletes should undergo preparticipation screening by qualified professionals.​

Prevention of Exercise-Related Cardiac Events

• Athletes with known cardiac conditions or a family history should be evaluated prior to competition using established guidelines.​

• Health care facilities should ensure that their staff are trained in managing cardiac emergencies, have a specified plan, and have appropriate resuscitation equipment.​

• Physically active individuals should modify their exercise program in response to variations in their exercise capacity, habitual activity level, and the environment.​