HEALTH QUESTION

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CHAPTER 11: Physical Fitness Being physically active is one of the most important steps that Americans of all ages can take to improve their health. The benefits of physical activity occur in generally healthy people, in people at risk of developing chronic diseases, and in people with current chronic conditions or disabilities. Studies have examined the role of physical activity in many groups—men and women, children, teens, adults, older adults, people with disabilities, and women during pregnancy and the postpartum period. These studies have focused on the role that physical activity plays in many health outcomes, including:

• Premature (early) death; • Diseases such as coronary heart disease, stroke, some cancers, type 2 diabetes,

osteoporosis, and depression; • Risk factors for disease, such as high blood pressure and high blood cholesterol; • Physical fitness, such as aerobic capacity, and muscle strength and endurance • Functional capacity (the ability to engage in activities needed for daily living); • Mental health, such as depression and cognitive function; and • Injuries or sudden heart attacks.

There have also been additional studies by the Advisory Committee of the U.S. Department of Health and Human Services. The Advisory Committee rated the evidence of health benefits of physical activity as strong, moderate, or weak. To do so, the Committee considered the type, number, and quality of studies available, as well as consistency of findings across studies that addressed each outcome. The Committee also considered evidence for causality and dose response in assigning the strength-of-evidence rating.

Section 11.1 Health Benefits Associated With Regular Physical Activity

Children and Adolescents

Strong evidence • Improved cardiorespiratory and muscular fitness • Improved bone health • Improved cardiovascular and metabolic health biomarkers • Favorable body composition Moderate evidence • Reduced symptoms of depression

Adults and Older Adults

Strong evidence • Lower risk of early death

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• Lower risk of coronary heart disease • Lower risk of stroke • Lower risk of high blood pressure • Lower risk of adverse blood lipid profile • Lower risk of type 2 diabetes • Lower risk of metabolic syndrome • Lower risk of colon cancer • Lower risk of breast cancer • Prevention of weight gain • Weight loss, particularly when combined with reduced calorie intake • Improved cardiorespiratory and muscular fitness • Prevention of falls • Reduced depression • Better cognitive function (for older adults) Moderate to strong evidence • Better functional health (for older adults) • Reduced abdominal obesity Moderate evidence • Lower risk of hip fracture • Lower risk of lung cancer • Lower risk of endometrial cancer • Weight maintenance after weight loss • Increased bone density • Improved sleep quality These studies have also prompted questions as to what type and how much physical activity is needed for various health benefits. That led to the development of The Physical Activity Guidelines for Americans, which gives guidance on the amount of physical activity that will provide health benefits for all Americans. Although some health benefits seem to begin with as little as 60 minutes (1 hour) a week, research shows that a total amount of 150 minutes (2 hours and 30 minutes) a week of moderate-intensity aerobic activity, such as brisk walking, consistently reduces the risk of many chronic diseases and other adverse health outcomes. For more details on the Physical Activity Guidelines for Americans please see the table below:

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Although the Guidelines focus on the health benefits of physical activity, these benefits are not the only reason why people are active. Physical activity gives people a chance to have fun, be with friends and family, enjoy the outdoors, improve their personal appearance, and improve their fitness so that they can participate in more intensive physical activity or sporting events. Some people are active because they feel it gives them certain health benefits (such as feeling more energetic) that aren’t yet conclusively proven for the general population. The Guidelines encourage people to be physically active for any and all reasons that are meaningful for them. Nothing in the Guidelines is intended to mean that health benefits are the only reason to do physical activity.

Section 11.2 Health Related Components of Physical Fitness

In many studies related to physical fitness and health, researchers have focused on exercise, as well as on the more broadly defined concept of physical activity. Physical activity is defined by the World Health Organization as any bodily movement produced by skeletal muscles that requires energy expenditure, while exercise is a form of physical activity that is planned, structured, repetitive, and performed with the goal of improving health or fitness. So, although all exercise is physical activity, not all physical activity is exercise. Although physical activity and exercise are defined concepts, the ultimate focus of the health related components of physical fitness is to provide a framework for components that are necessary for good health. They are cardiorespiratory (CR) endurance (also called aerobic endurance), flexibility, muscular strength, muscular endurance, and body composition.

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Cardiorespiratory endurance

(aerobic endurance) The ability of the heart, blood vessels, and lungs to work together to accomplish three goals: 1) deliver oxygen to body tissues; 2) deliver nutrients; 3) remove waste products. CR endurance exercises involve large muscle groups in prolonged, dynamic movement (ex. running, swimming, etc) Examples of Different Aerobic Physical Activities and Intensities Moderate Intensity

• Walking briskly (3 miles per hour or faster, but not race-walking) • Water aerobics • Bicycling slower than 10 miles per hour • Tennis (doubles) • Ballroom dancing • General gardening

Vigorous Intensity • Racewalking, jogging, or running • Swimming laps • Tennis (singles) • Aerobic dancing • Bicycling 10 miles per hour or faster • Jumping rope • Heavy gardening (continuous digging or hoeing, with heart rate increases) • Hiking uphill or with a heavy backpack

Frequency and Duration

Aerobic physical activity should preferably be spread throughout the week. Research studies consistently show that activity performed on at least 3 days a week produces health benefits. Spreading physical activity across at least 3 days a week may help to reduce the risk of injury and avoid excessive fatigue. Both moderate- and vigorous-intensity aerobic activity should be performed in episodes of at least 10 minutes. Episodes of this duration are known to improve cardiovascular fitness and some risk factors for heart disease and type 2 diabetes.

Intensity

The Guidelines for adults focus on two levels of intensity: moderate-intensity activity and vigorous–intensity activity. To meet the Guidelines, adults can do either moderate-intensity or vigorous-intensity aerobic activities, or a combination of both. It takes less time to get the same benefit from vigorous-intensity activities as from moderate-intensity activities. A general rule of thumb is that 2 minutes of moderate-intensity activity counts the same as 1

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minute of vigorous-intensity activity. For example, 30 minutes of moderate-intensity activity a week is roughly the same as 15 minutes of vigorous-intensity activity. A person doing moderate-intensity aerobic activity can talk, but not sing, during the activity. A person doing vigorous intensity activity cannot say more than a few words without pausing for a breath.

Muscular Strength and Endurance

Muscular strength: The ability of muscles to exert maximal effort. Muscular endurance: The ability of muscles to exert submaximal effort repetitively (contract over and over again or hold a contraction for a long time).

Activities for Muscular Strength and Endurance

These kind of activities, which includes resistance training and lifting weights, causes the body's muscles to work or hold against an applied force or weight. These activities often involve relatively heavy objects, such as weights, which are lifted multiple times to train various muscle groups. Muscle-strengthening activity can also be done by using elastic bands or body weight for resistance (climbing a tree or doing push-ups, for example). Activities for Muscular Strength and Endurance also has three components:

• Intensity, or how much weight or force is used relative to how much a person is able to lift;

• Frequency, or how often a person does muscle strengthening activity; and • Repetitions, or how many times a person lifts a weight (analogous to duration for

aerobic activity). Repetitions play a key role in determining if an activity is improving muscular strength or endurance. Low repetitions with more weight will focus more on muscular strength, while high repetitions with less weight will focus more on muscular endurance. The effects of muscle-strengthening activity are limited to the muscles doing the work. It's important to work all the major muscle groups of the body: the legs, hips, back, abdomen, chest, shoulders, and arms.

Muscle-strengthening activities provide additional benefits not found with aerobic activity. The benefits of muscle-strengthening activity include increased bone strength and muscular fitness. Muscle-strengthening activities can also help maintain muscle mass during a program of weight loss. Muscle-strengthening activities make muscles do more work than they are accustomed to doing. That is, they overload the muscles. Resistance training, including weight training, is a familiar example of muscle-strengthening activity. Other examples include working with resistance bands, doing calisthenics that use body weight for resistance (such as push-ups, pull-ups, and sit-ups), carrying heavy loads, and heavy gardening (such as digging or hoeing). Muscle-strengthening activities count if they involve a moderate to high level of intensity or effort and work the major muscle groups of the body: the legs, hips, back, chest, abdomen, shoulders, and arms. Muscle strengthening activities for all the major muscle groups should

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be done at least 2 days a week. No specific amount of time is recommended for muscle strengthening, but muscle- strengthening exercises should be performed to the point at which it would be difficult to do another repetition without help. When resistance training is used to enhance muscle strength, one set of 8 to 12 repetitions of each exercise is effective, although two or three sets may be more effective. Development of muscle strength and endurance is progressive over time. Increases in the amount of weight or the days a week of exercising will result in stronger muscles.

Flexibility

Flexibility is the ability of moving a joint through the range of motion. Flexibility is an important part of physical fitness. Some types of physical activity, such as dancing, require more flexibility than others. Stretching exercises are effective in increasing flexibility, and thereby can allow people to more easily do activities that require greater flexibility. For this reason, flexibility activities are an appropriate part of a physical activity program, even though they have no known health benefits and it is unclear whether they reduce risk of injury. Time spent doing flexibility activities by themselves does not count toward meeting the aerobic or muscle-strengthening Guidelines. Although there are not specific national guidelines for flexibility, adults should do flexibility exercises at least two or three days each week to improve range of motion. This can be done by holding a stretch for 10-30 seconds to the point of tightness or slight discomfort. Repeat each stretch two to four times, accumulating 60 seconds per stretch.

Body composition

The percentage of the body composed of lean tissue (muscle, bone, fluids, etc.) and fat tissue. Changes in body composition usually occur as a result of improvements in the other components of health related physical fitness, as well as changes in eating habits. This is discussed in more detail in the Weight Management and Healthy Eating Chapter. There are also other components of fitness related to sports performance rather than just health. They are called skill-related components of fitness or motor fitness and include power, speed, agility, balance, and coordination. For the purpose of this class we will focus mainly on the health-related components of fitness.

Section 11.3 Adding Physical Activity to Your Life

Overcoming Barrier to Being Physical Active

Given the health benefits of regular physical activity, we might have to ask why two out of three (60%) Americans are not active at recommended levels.

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Many technological advances and conveniences that have made our lives easier and less active, as well as many personal variables, including physiological, behavioral, and psychological factors, may affect our plans to become more physically active. In fact, the 10 most common reasons adults cite for not adopting more physically active lifestyles are (Sallis and Hovell, 1990; Sallis et al., 1992):

• Do not have enough time to exercise • Find it inconvenient to exercise • Lack self-motivation • Do not find exercise enjoyable • Find exercise boring • Lack confidence in their ability to be physically active (low self-efficacy) • Fear being injured or have been injured recently • Lack self-management skills, such as the ability to set personal goals, monitor

progress, or reward progress toward such goals • Lack encouragement, support, or companionship from family and friends, and • Do not have parks, sidewalks, bicycle trails, or safe and pleasant walking paths

convenient to their homes or offices. Understanding common barriers to physical activity and creating strategies to overcome them may help you make physical activity part of your daily life. Please visit the link below to see a full table of SUGGESTIONS FOR OVERCOMING PHYSICAL ACTIVITY BARRIERS: https://courses.candelalearning.com/fitness1xmaster/chapter/adding-physical- activity-to-your-life/

Creating your own Fitness Program

The first step to implementing a fitness program is to identify your goals. As discussed in earlier chapters, goals should be specific, measurable, action-oriented, realistic and time- bound (SMART). Progress can be difficult to track if goals are vague and open-ended, such as “I will exercise more.” Here is an example of a SMART goal for fitness:

• Specific: “I will walk for 30 minutes a day 3-5 days per week” • Measurable: “I will improve my resting heart rate over the next month” • Action-Oriented: “I will research walking routes around my home and campus” • Realistic: “I will increase my walking to 45 minutes per day in one month” • Time Bound: “I will try this walking program for one month and then reassess my

goals” You can also make a SMART Goal in one statement, such as “I will walk for 30 minutes 3-5 days per week for the next month in order to improve my resting heart rate.”

FITT Principle

Using the FITT principle is one way remember the guidelines for physical activity and create a prescription for improvement in your health-related physical fitness.

• Frequency: how often a person performs a health-related physical activity. • Intensity: how hard a person exercises during a physical activity period. Intensity

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can be measured in different ways, depending on the related health-related component.

• Time: also known as duration. Refers to the amount of time or repetitions when performing a physical activity.

• Type: the kind of exercise or physical activity a person is performing. Adapted from: http://www.ode.state.or.us/teachlearn/subjects/pe/curriculum/fittprinciple.pdf)

Measuring Intensity

TARGET HEART RATE AND ESTIMATED MAXIMUM HEART RATE Exercise intensity can be measured using either heart rate or the rating of perceived exertion (RPE) method. We will look at each of these methods in turn. There are two methods of using heart rate to measure exercise intensity: the percentage of maximal heart rate method and the heart rate reserve (HRR), or karvonen method. As its name suggests, the percentage of maximal heart rate method involves prescribing exercise at a certain percentage of maximum heart rate. To find out a person’s true maximum heart rate we need to measure it in a laboratory. However, for most people this is impractical; therefore we can estimate maximum heart rate using the formula ‘220 – age’ (see Box 1).

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Box 1: Percentage heart rate method Case study: ‘Mariella’, age 30 Step 1 – Calculate maximum heart rate (HRmax) Estimated HRmax = 220 – age = 220 – 30 = 190 bpm (beats per minute) Step 2 – Calculate exercise intensity ACSM guidelines = 55–90% of HRmax Lower target (55%) = 190 × 55% = 190 × 0.55 = 104.5 bpm (we would round this up to 105 bpm) Upper target (90%) = 190 × 90% = 190 × 0.90 = 171 bpm This formula gives us an idea of maximum heart rate, but we must remember that it is just an estimate and not completely accurate. Therefore using this method, according to ACSM guidelines, Mariella should exercise at a heart rate somewhere between 105 and 171 bpm. This is quite a wide range so, depending on her fitness levels, you would need to decide whether to prescribe Mariella exercise to the upper or lower end of this scale. Please note that there are online calculators available to calculate all of this information for you. Once such calculator can be found at: http://www.sparkpeople.com/resource/calculator_target.asp The HRR method is thought to be more accurate than the percentage of maximal heart rate method because it takes the individual’s resting heart rate into account. The formula for calculating HRR can be seen in Box 2. The ACSM recommends that to improve aerobic fitness, exercise intensity should be set at either 40–85 per cent of (HRR) or 55–90 per cent of maximum heart rate (HRmax) (Pollock et al., 1998). These ranges are deliberately broad to reflect different levels of fitness; that is, someone with relatively low levels of fitness who has just started an exercise programme may need to work on the lower end of the scale, whereas someone who has a higher level of fitness, perhaps who has been exercising for a while, may need to work at an intensity towards the upper end of the scale. This demonstrates the importance of progression in an exercise programme. Box 2: Heart rate reserve method Case study: ‘Mariella’, age 30 Step 1 – Calculate maximum heart rate (HRmax) Estimated HRmax = 220 - age = 220 – 30 = 190 bpm (beats per minute)

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Step 2 – Measure resting heart rate (HRrest) You would measure this either using a heart rate monitor or manually, using your fingers. Ideally it should be measured first thing in the morning. Let's imagine that Mariella's HRrest has been measured at 70 bpm. Step 3 – Calculate heart rate reserve (HRR) HRR = HRmax – HRrest = 190 – 70 = 120 bpm Step 4 – Calculate exercise intensity ACSM guidelines = 40–85% HRR Lower target (40%) = (HHR × 40%) + HRrest = (120 × 0.40) + 70 = 48 + 70 = 118 bpm Upper target (85%) = (HHR × 85%) + HRrest = (120 × 0.85) + 70 = 102 + 70 = 172 bpm Using this method, according to ACSM guidelines, Mariella should exercise somewhere between 118 and 172 bpm.

Borg Scale

An alternative to using heart rate methods is the RPE method of measuring exercise intensity. However, you should note that it is difficult to give a general recommendation for RPE, as it is by its very nature open to personal interpretation; that is, what I consider to be a 12 may be different to what you consider to be a 12. RPE can be a useful way of measuring exercise intensity when heart rate monitoring is difficult or inappropriate. For example, some types of medication (e.g. beta blockers) given to people with hypertension lower the heart rate, and therefore heart rate measurement is not appropriate for people on this type of medication. The Borg Rating of Perceived Exertion (RPE) Scale is one way to measure perceived exertion. In medicine, this is used to document the patient’s exertion during a test, and sports coaches use the scale to assess the intensity of training and competition. The original scale introduced by Gunnar Borg rated exertion on a scale of 6-20. The seemingly odd range of 6-20 is to follow the general heart rate of a healthy adult by multiplying by 10. For instance, a perceived exertion of 12 would be expected to coincide with a heart rate of roughly 120 beats per minute.

SET POINTS ON SCALE It ranges from 6 to 20, where 6 means “no exertion at all” and 20 means “maximal exertion.” Choose the number from below that best describes your level of exertion. This

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will give you a good idea of the intensity level of your activity, and you can use this information to speed up or slow down your movements to reach your desired range. Try to appraise your feeling of exertion as honestly as possible, without thinking about what the actual physical load is. Your own feeling of effort and exertion is important, not how it compares to other people’s. Look at the scales and the expressions and then give a number. 6 No exertion at all 7 Extremely light (7.5) 8 9 Very light 10 11 Light 12 13 Somewhat hard 14 15 Hard 16 17 Very hard 18 19 Extremely hard 20 Maximal exertion 9 corresponds to “very light” exercise. For a healthy person, it is like walking slowly at his or her own pace for some minutes. 13 On the scale is “somewhat hard” exercise, but it still feels OK to continue. 17, Or “very hard,” is very strenuous. A healthy person can still go on, but he or she really has to push him- or herself. It feels very heavy, and the person is very tired. 19 on the scale is an extremely strenuous exercise level. For most people this is the most strenuous exercise they have ever experienced. TAKING YOUR HEART RATE Generally, to determine whether you are exercising within the heart rate target zone, you must stop exercising briefly to take your pulse. You can take the pulse at the neck, the wrist, or the chest. We recommend the wrist. You can feel the radial pulse on the artery of the wrist in line with the thumb. Place the tips of the index and middle fingers over the artery and press lightly. Do not use the thumb. Take a full 60-second count of the heartbeats, or take for 30 seconds and multiply by 2. Start the count on a beat, which is

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counted as “zero.” If this number falls between 85 and 119 bpm in the case of the 50-year- old person, he or she is active within the target range for moderate-intensity activity.

Section 11.4 Implementing Your Fitness Plan

The Beneficial Effects of Increasing Physical Activity: It's About Overload, Progression, and Specificity

Creating a safe and effective fitness program involves knowing certain basic principles of physical fitness: overload, progression, and specificity. Overload is the physical stress placed on the body when physical activity is greater in amount or intensity than usual. The body's structures and functions respond and adapt to these stresses. For example, aerobic physical activity places a stress on the cardiorespiratory system and muscles, requiring the lungs to move more air and the heart to pump more blood and deliver it to the working muscles. This increase in demand increases the efficiency and capacity of the lungs, heart, circulatory system, and exercising muscles. In the same way, muscle–strengthening and bone-strengthening activities overload muscles and bones, making them stronger. Progression is closely tied to overload. Once a person reaches a certain fitness level, he or she progresses to higher levels of physical activity by continued overload and adaptation. Small, progressive changes in overload help the body adapt to the additional stresses while minimizing the risk of injury. Specificity means that the benefits of physical activity are specific to the body systems that are doing the work. For example, aerobic physical activity largely benefits the body's cardiovascular system. These principles should be taken into consideration during any exercise program if you expect to meet your goals.

Designing a program

Warm-up and Cool down Activities Warm-up and cool-down activities are an important part of a person’s physical activity

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plan. Commonly, the warm-up and cool-down involve doing an activity at a slower speed or lower intensity. A warm-up before moderate-or vigorous-intensity aerobic activity allows a gradual increase in heart rate and breathing at the start of the episode of activity. A cool- down after activity allows a gradual decrease at the end of the episode. Time spent doing warm-up and cool-down may count toward meeting the aerobic activity Guidelines if the activity is at least moderate intensity (for example, walking briskly as a warm-up before jogging). A warm-up for muscle-strengthening activity commonly involves doing exercises with lighter weight.

Physical Activity in a Weight Control Plan

The health benefits of physical activity are generally independent of body weight. The good news for people needing to lose weight is that regular physical activity provides major health benefits, no matter how their weight changes over time. Along with appropriate dietary intake, physical activity is an important part of maintaining healthy weight, losing weight, and keeping extra weight off once it has been lost. Physical activity also helps reduce abdominal fat and preserve muscle during weight loss. Adults should aim for a healthy, stable body weight. The amount of physical activity necessary to achieve this weight varies greatly from person to person. The first step in achieving or maintaining a healthy weight is to meet the minimum level of physical activity in the Guidelines. For some people, this will result in a stable and healthy body weight, but for many it may not. People who are at a healthy body weight but slowly gaining weight can either gradually increase the level of physical activity (toward the equivalent of 300 minutes a week of moderate-intensity aerobic activity), or reduce caloric intake, or both, until their weight is stable. By regularly checking body weight, people can find the amount of physical activity that works for them. Many adults will need to do more than the 150 minutes a week of moderate-intensity aerobic physical activity as part of a program to lose weight or keep it off. These adults should do more physical activity and/or further reduce their caloric intake. Some people will need to do the equivalent of 300 or more minutes of moderate-intensity physical activity a week to meet their weight-control goals. Combined with restricting caloric intake, these adults should gradually increase minutes or the intensity of aerobic physical activity per week, to the point at which the physical activity is effective in achieving a healthy weight. Adults should strongly consider walking as one good way to get aerobic physical activity. Many studies show that walking has health benefits and a low risk of injury. It can be done year-round and in many settings. It is important to remember that all activities—both baseline and physical activity—“count” for energy balance. Active choices, such as taking the stairs rather than the elevator or adding short episodes of walking to the day, are

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examples of activities that can be helpful in weight control. For weight control, vigorous- intensity activity is far more time-efficient than moderate-intensity activity. For example, an adult who weighs 165 pounds (75 kg) will burn 560 calories from 150 minutes of brisk walking at 4 miles an hour (these calories are in addition to the calories normally burned by a body at rest). That person can burn the same number of additional calories in 50 minutes by running 5 miles at a 10 minutes-per-mile pace.

Achieving Your Physical Activities: The Possibilities are endless

These examples show how it’s possible to meet the Guidelines by doing moderate-intensity or vigorous-intensity activity or a combination of both. Physical activity at this level provides substantial health benefits. Ways to get the equivalent of 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic physical activity a week plus muscle-strengthening activities:

• Thirty minutes of brisk walking (moderate intensity) on 5 days, exercising with resistance bands (muscle strengthening) on 2 days;

• Twenty-five minutes of running (vigorous intensity) on 3 days, lifting weights on 2 days (muscle strengthening);

• Thirty minutes of brisk walking on 2 days, 60 minutes (1 hour) of social dancing (moderate intensity) on 1 evening, 30 minutes of mowing the lawn (moderate intensity) on 1 afternoon, heavy gardening (muscle strengthening) on 2 days;

• Thirty minutes of an aerobic dance class on 1 morning (vigorous intensity), 30 minutes of running on 1 day (vigorous intensity), 30 minutes of brisk walking on 1 day (moderate intensity), calisthenics (such as sit-ups, push-ups) on 3 days (muscle strengthening);

• Thirty minutes of biking to and from work on 3 days (moderate intensity), playing softball for 60 minutes on 1 day (moderate intensity), using weight machines on 2 days (muscle-strengthening on 2 days); and

• Forty-five minutes of doubles tennis on 2 days (moderate intensity), lifting weights after work on 1 day (muscle strengthening), hiking vigorously for 30 minutes and rock climbing (muscle strengthening) on 1 day.

Ways to be Even More Active For adults who are already doing at least 150 minutes of moderate-intensity physical activity, here are a few ways to do even more. Physical activity at this level has even greater health benefits.

• Forty-five minutes of brisk walking every day, exercising with resistance bands on 2 or 3 days;

• Forty-five minutes of running on 3 or 4 days, circuit weight training in a gym on 2 or 3 days;

• Thirty minutes of running on 2 days, 45 minutes of brisk walking on 1 day, 45 minutes of an aerobics and weights class on 1 day, 90 minutes (1 hour and 30 minutes) of social dancing on 1 evening, 30 minutes of mowing the lawn, plus some heavy garden work on 1 day;

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• Ninety minutes of playing soccer on 1 day, brisk walking for 15 minutes on 3 days, lifting weights on 2 days; and

• Forty-five minutes of stationary bicycling on 2 days, 60 minutes of basketball on 2 days, calisthenics on 3 days.

Be Safe and Active Although physical activity has many health benefits, injuries and other adverse events do sometimes happen. The most common injuries affect the musculoskeletal system (the bones, joints, muscles, ligaments, and tendons). Other adverse events can also occur during activity, such as overheating and dehydration. On rare occasions, people have heart attacks during activity. The good news is that scientific evidence strongly shows that physical activity is safe for almost everyone. Moreover, the health benefits of physical activity far outweigh the risks. Still, people may hesitate to become physically active because of concern they’ll get hurt. For these people, there is even more good news: They can take steps that are proven to reduce their risk of injury and adverse events. The Guidelines in this module provide advice to help people do physical activity safely. Most advice applies to people of all ages. Specific guidance for particular age groups and people with certain conditions is also provided.

Physical Activity is Safe for Almost Everyone

Most people are not likely to be injured when doing moderate-intensity activities in amounts that meet the Physical Activity Guidelines. However, injuries and other adverse events do sometimes happen. The most common problems are musculoskeletal injuries. Even so, studies show that only one such injury occurs for every 1,000 hours of walking for exercise, and fewer than four injuries occur for every 1,000 hours of running. Both physical fitness and total amount of physical activity affect risk of musculoskeletal injuries. People who are physically fit have a lower risk of injury than people who are not. People who do more activity generally have a higher risk of injury than people who do less activity. To do physical activity safely and reduce risk of injuries and other adverse events, people should:

• Understand the risks and yet be confident that physical activity is safe for almost everyone.

• Choose to do types of physical activity that are appropriate for their current fitness level and health goals, because some activities are safer than others.

• Increase physical activity gradually over time whenever more activity is necessary to meet guidelines or health goals. Inactive people should “start low and go slow” by gradually increasing how often and how long activities are done.

• Protect themselves by using appropriate gear and sports equipment, looking for safe environments, following rules and policies, and making sensible choices about when, where, and how to be active.

• Be under the care of a health-care provider if they have chronic conditions or

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symptoms. People with chronic conditions and symptoms should consult their health-care provider about the types and amounts of activity appropriate for them.

Choose Appropriate Types and Amounts of Activity People can reduce their risk of injury by choosing appropriate types of activity. The safest activities are moderate intensity and low impact, and don’t involve purposeful collision or contact. Walking for exercise, gardening or yard work, bicycling or exercise cycling, dancing, swimming, and golf are activities with the lowest injury rates. In the amounts commonly done by adults, walking (a moderate–intensity and low-impact activity) has a third or less of the injury risk of running (a vigorous-intensity and higher impact activity). The risk of injury for a type of physical activity can also differ according to the purpose of the activity. For example, recreational bicycling or bicycling for transportation leads to fewer injuries than training for and competing in bicycle races. People who have had a past injury are at risk of injuring that body part again. The risk of injury can be reduced by performing appropriate amounts of activity and setting appropriate personal goals. Performing a variety of different physical activities may also reduce the risk of overuse injury. The risk of injury to bones, muscles, and joints is directly related to the gap between a person’s usual level of activity and a new level of activity. Increase Physical Activity Gradually Over Time Scientific studies indicate that the risk of injury to bones, muscles, and joints is directly related to the gap between a person’s usual level of activity and a new level of activity. The size of this gap is called the amount of overload. Creating a small overload and waiting for the body to adapt and recover reduces the risk of injury. When amounts of physical activity need to be increased to meet the Guidelines or personal goals, physical activity should be increased gradually over time, no matter what the person’s current level of physical activity. Scientists have not established a standard for how to gradually increase physical activity over time. The following recommendations give general guidance for inactive people and those with low levels of physical activity on how to increase physical activity:

• Use relative intensity (intensity of the activity relative to a person’s fitness) to guide the level of effort for aerobic activity.

• Generally, start with relatively moderate-intensity aerobic activity. Avoid relatively vigorous-intensity activity, such as shoveling snow or running. Adults with a low level of fitness may need to start with light activity, or a mix of light- to moderate- intensity activity.

• First, increase the number of minutes per session (duration), and the number of days per week (frequency) of moderate-intensity activity. Later, if desired, increase the intensity.

• Pay attention to the relative size of the increase in physical activity each week, as this is related to injury risk. For example, a 20-minute increase each week is safer for a person who does 200 minutes a week of walking (a 10 percent increase), than

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for a person who does 40 minutes a week (a 50 percent increase). The available scientific evidence suggests that adding a small and comfortable amount of light- to moderate–intensity activity, such as 5 to 15 minutes of walking per session, 2 to 3 times a week, to one’s usual activities has a low risk of musculoskeletal injury and no known risk of severe cardiac events. Because this range is rather wide, people should consider three factors in individualizing their rate of increase: age, level of fitness, and prior experience. The amount of time required to adapt to a new level of activity probably depends on age. Youth and young adults probably can safely increase activity by small amounts every week or 2. Older adults appear to require more time to adapt to a new level of activity, in the range of 2 to 4 weeks. Level of Fitness Less fit adults are at higher risk of injury when doing a given amount of activity, compared to fitter adults. Slower rates of increase over time may reduce injury risk. This guidance applies to overweight and obese adults, as they are commonly less physically fit. Prior Experience People can use their experience to learn to increase physical activity over time in ways that minimize the risk of overuse injury. Generally, if an overuse injury occurred in the past with a certain rate of progression, a person should increase activity more slowly the next time. Take Appropriate Precautions Taking appropriate precautions means using the right gear and equipment, choosing safe environments in which to be active, following rules and policies, and making sensible choices about how, when, and where to be active. Use Protective Gear and Appropriate Equipment Using personal protective gear can reduce the frequency of injury. Personal protective gear is something worn by a person to protect a specific body part. Examples include helmets, eyewear and goggles, shin guards, elbow and knee pads, and mouth guards. Using appropriate sports equipment can also reduce risk of injury. Sports equipment refers to sport or activity-specific tools, such as balls, bats, sticks, and shoes. For the most benefit, protective equipment and gear should be:

1 The right equipment for the activity 2 Appropriately fitted 3 Appropriately maintained 4 Used consistently and correctly.

Be Active in Safe Environments People can reduce their injury risks by paying attention to the places they choose to be

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active. To help themselves stay safe, people can look for: • Physical separation from motor vehicles, such as sidewalks, walking paths, or bike

lanes; • Neighborhoods with traffic-calming measures that slow down traffic; • Places to be active that are well-lighted, where other people are present, and that

are well-maintained (no litter, broken windows); • Shock-absorbing surfaces on playgrounds; • Well-maintained playing fields and courts without holes or obstacles; • Breakaway bases at baseball and softball fields; and • Padded and anchored goals and goal posts at soccer and football fields.

Follow Rules and Policies That Promote Safety Rules, policies, legislation, and laws are potentially the most effective and wide-reaching way to reduce activity-related injuries. To get the benefit, individuals should look for and follow these rules, policies, and laws. For example, policies that promote the use of bicycle helmets reduce the risk of head injury among cyclists. Rules against diving into shallow water at swimming pools prevent head and neck injuries. Make Sensible Choices about How, When, and Where To Be Active A person’s choices can obviously influence the risk of adverse events. By making sensible choices, injuries and adverse events can be prevented. Consider weather conditions, such as extremes of heat and cold. For example, during very hot and humid weather, people lessen the chances of dehydration and heat stress by:

• Exercising in the cool of early morning as opposed to mid-day heat; • Switching to indoor activities (playing basketball in the gym rather than on the

playground); • Changing the type of activity (swimming rather than playing soccer); • Lowering the intensity of activity (walking rather than running); and • Paying close attention to rest, shade, drinking enough fluids, and other ways to

minimize effects of heat. Inactive people who gradually progress over time to relatively moderate-intensity activity have no known risk of sudden cardiac events, and very low risk of bone, muscle, or joint injuries. Exposure to air pollution is associated with several adverse health outcomes, including asthma attacks and abnormal heart rhythms. People who can modify the location or time of exercise may wish to reduce these risks by exercising away from heavy traffic and industrial sites, especially during rush hour or times when pollution is known to be high. However, current evidence indicates that the benefits of being active, even in polluted air, outweigh the risk of being inactive. Advice from Health-Care Providers The protective value of a medical consultation for persons with or without chronic diseases who are interested in increasing their physical activity level is not established. People

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without diagnosed chronic conditions (such as diabetes, heart disease, or osteoarthritis) and who do not have symptoms (such as chest pain or pressure, dizziness, or joint pain) do not need to consult a health-care provider about physical activity. Inactive people who gradually progress over time to relatively moderate-intensity activity have no known risk of sudden cardiac events, and very low risk of bone, muscle, or joint injuries. A person who is habitually active with moderate-intensity activity can gradually increase to vigorous intensity without needing to consult a health-care provider. People who develop new symptoms when increasing their levels of activity should consult a health-care provider. Health-care providers can provide useful personalized advice on how to reduce risk of injuries. For people who wish to seek the advice of a health-care provider, it is particularly appropriate to do so when contemplating vigorous-intensity activity, because the risks of this activity are higher than the risks of moderate-intensity activity. The choice of appropriate types and amounts of physical activity can be affected by chronic conditions. People with symptoms or known chronic conditions should be under the regular care of a health-care provider. In consultation with their provider, they can develop a physical activity plan that is appropriate for them. People with chronic conditions typically find that moderate-intensity activity is safe and beneficial. However, they may need to take special precautions. For example, people with diabetes need to pay special attention to blood sugar control and proper footwear during activity. References Overall Physical Activity Chapter http://hlth21fall2012.wikispaces.com/Module+07 Brief Health Benefits and Safety https://courses.candelalearning.com/fitness1xmaster/chapter/health-safety-ada- compliance/ Overcoming barriers to physical Activity https://courses.candelalearning.com/fitness1xmaster/chapter/adding-physical-activity- to-your-life/ Components of Health Related Physical Fitness https://courses.candelalearning.com/fitness1xmaster/chapter/introduction-to-fitness- and-wellness/ Components of Skill Related Physical Fitness

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http://www.centralcougars.org/pehedr/phyeduindex_files/Skill- related%20components.pdf https://sites.google.com/site/bensonpehealth/health-and-skill-related-fitness- components https://www.ocps.net/lc/southwest/mso/AC/subject/Documents/Health%20- %20Skills%20Fitness%20Components.pdf Physical Activity Guidelines for Americans https://courses.candelalearning.com/fitness1xmaster/chapter/introducing-the-2008- physical-activity-guidelines-for-americans/ Health Benefits of Physical Activity https://courses.candelalearning.com/fitness1xmaster/chapter/physical-activity-has- many-health-benefits/ Guidelines for Adults https://courses.candelalearning.com/fitness1xmaster/chapter/active-adults/ https://health.gov/paguidelines/ https://health.gov/paguidelines/pdf/paguide.pdf Avoiding Injury and Staying Safe during Physical Activity https://courses.candelalearning.com/fitness1xmaster/chapter/safe-and-active/ Borgs Rating of Perceived Exertion https://courses.candelalearning.com/fitness1xmaster/chapter/borg-rating-of-perceived- exertion-rpe-scale/ Target Heart Rate and Estimated Maximum Heart Rate https://courses.candelalearning.com/fitness1xmaster/chapter/target-heart-rate-and- estimated-maximum-heart-rate/ SMART Goals https://www.acefitness.org/fitfacts/pdfs/fitfacts/itemid_2637.pdf