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Medicine LibreTexts

11.3: Physical Fitness and Physical Activity

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  • Learning Objectives

    • Differentiate between physical fitness and physical activity.
    • Describe the components of physical fitness.
    • List the benefits of physical activity.

    Becoming physically fit and participating in physical activity are important, yet distinct, parts of achieving optimal health. Physical fitness is the ability to carry out daily tasks without getting too tired and with enough leftover energy to enjoy leisure-time pursuits. Physical activity is any muscle movement that increases energy expenditure. Participating in physical activity increases physical fitness.

    Components of Physical Fitness

    There are multiple components of physical fitness:

    • cardiorespiratory fitness
    • musculoskeletal fitness
    • flexibility
    • balance
    • speed

    Cardiorespiratory fitness is the ability to perform whole-body exercises at moderate-to-vigorous intensity for an extended period of time.1 Aerobic activities such as walking, running, and swimming help increase cardiorespiratory endurance. The Physical Activity Guidelines for Americans recommend at least 150 minutes (2 hours and 30 minutes) to 300 minutes (5 hours) a week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) to 150 minutes (2 hours and 30 minutes) a week of vigorous-intensity aerobic physical activity.1 Activity should be spread throughout the week. If this level of activity seems like too much, know that some physical activity is better than none.

    Musculoskeletal fitness includes both muscle strength and muscle endurance. Musculoskeletal fitness training can involve the use of resistance machines, resistance bands, free weights, or other tools that can be found at a gym or can be homemade. You can also use your own body weight and do push-ups, leg squats, abdominal crunches, and other exercises to build your muscles. Muscular strength is increased by lifting weights (or other resistance training) with heavier weights for fewer repetitions. Muscle endurance is typically achieved by using lighter weights for more repetitions. The Physical Activity Guidelines for Americans recommend strength training at least twice per week.1

    Flexibility is the range of motion available to your joints. Yoga, tai chi, pilates, and stretching exercises work to improve this element of fitness. Stretching not only improves your range of motion, it also promotes better posture, and helps you perform activities that can require greater flexibility, such as chores around the house.

    Balance is the ability to maintain equilibrium while moving or while stationary.1 Walking backward, standing on one leg, or using a balance board are examples of activities that can enhance balance. Balance tends to deteriorate with age, which can result in falls and fractures.

    Speed refers to the ability to move the body quickly. When first starting an activity, your speed may be slower. To reduce risk of injury, increase the speed gradually over a period of weeks or months.

    Some forms of exercise confer multiple benefits, which can help you to balance the different components of physical fitness. For example, riding a bicycle for thirty minutes or more builds cardiorespiratory fitness, musculoskeletal fitness, and balance. Some forms of yoga build musculoskeletal fitness, flexibility, and balance. However, addressing all of the components of physical fitness generally requires incorporating a range of activities into your regular routine.

    Benefits of Physical Activity

    Regular physical activity is one of the best things you can do to achieve optimal health. Physical activity provides a wealth of benefits including:

    • Healthier weight. Exercise, along with a healthy, balanced eating plan, can help you lose extra weight, maintain weight loss, or prevent excessive weight gain.
    • Reduced risk of chronic disease. A regular routine can help to prevent or manage a wide range of conditions and concerns, such as cardiovascular disease, metabolic syndrome, Type 2 diabetes, and certain types of cancer.
    • Strong bones. Research shows that aerobic activity and strength training can slow the loss of bone density that typically accompanies aging.
    • Mood improvement. Aerobic activity, strength-training, and more contemplative activities such as yoga, all help break cycles of worry, absorption, and distraction, effectively draining tension from the body.
    • Reduced risk of depression, or limited symptoms of it. Some people have called exercise “nature’s antidepressant,” and studies have shown that physical activity reduces the risk of and helps people cope with the symptoms of depression.
    • Cognitive skills retention. Regular physical activity can help people maintain thinking, learning, and judgment as they age.
    • Better sleep. A good night’s sleep is essential for clear thinking, and regular exercise promotes healthy, sound sleep. It can also help you fall asleep faster and deepen your rest.

    Physical activity is recommended for everyone because a physically active lifestyle yields so many health benefits. Even small changes such as taking the stairs instead of the elevator, or parking farther away from a store to add a bit more walking into your day can lead to a more active lifestyle and set you on the road to optimal health. An important element of a more active lifestyle is to select activities that you enjoy and can integrate into your schedule smoothly, so you can maintain it.

    Key Takeaways

    • Physical fitness is an important part of the pursuit of optimal health.
    • The components of physical fitness are cardiorespiratory fitness, musculoskeletal fitness, flexibility, balance, and speed.
    • Physical activity yields multiple benefits in terms of preventing disease and promoting health.


    1. U.S. Department of Health and Human Services. Physical Activity Guidelines for Americans, 2nd edition. Washington, DC: U.S. Department of Health and Human Services; 2018. Accessed July 8, 2020.