State of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities
Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities. Physical fitness is generally achieved through proper nutrition, moderate-vigorous physical exercise, and sufficient rest.
Before the industrial revolution, fitness was defined as the capacity to carry out the day’s activities without undue fatigue. However, with automation and changes in lifestyles physical fitness is now considered a measure of the body’s ability to function efficiently and effectively in work and leisure activities, to be healthy, to resist hypokinetic diseases, and to meet emergency situations.
Fitness is defined as the quality or state of being fit. Around 1950, perhaps consistent with the Industrial Revolution and the treatise of World War II, the term “fitness” increased in western vernacular by a factor of ten. The modern definition of fitness describes either a person or machine’s ability to perform a specific function or a holistic definition of human adaptability to cope with various situations. This has led to an interrelation of human fitness and attractiveness that has mobilized global fitness and fitness equipment industries. Regarding specific function, fitness is attributed to persons who possess significant aerobic or anaerobic ability, i.e. endurance or strength. A well-rounded fitness program improves a person in all aspects of fitness compared to practising only one, such as only cardio/respiratory endurance or only weight training.
A comprehensive fitness program tailored to an individual typically focuses on one or more specific skills, and on age- or health-related needs such as bone health. Many sources also cite mental, social and emotional health as an important part of overall fitness. This is often presented in textbooks as a triangle made up of three points, which represent physical, emotional, and mental fitness. Physical fitness can also prevent or treat many chronic health conditions brought on by unhealthy lifestyle or aging. Working out can also help some people sleep better and possibly alleviate some mood disorders in certain individuals.
Developing research has demonstrated that many of the benefits of exercise are mediated through the role of skeletal muscle as an endocrine organ. That is, contracting muscles release multiple substances known as myokines, which promote the growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases.
The 2018 Physical Activity Guidelines for Americans were released by the U.S. Department of Health and Human Services to provide science-based guidance for people ages 3 years and older to improve their health by participating in regular physical activity. These guidelines recommend that all adults should move more and sit less throughout the day to improve health-related quality of life including mental, emotional, and physical health. For substantial health benefits, adults should perform at least 150 to 300 minutes of moderate-intensity, or 75 to 150 minutes per week of vigorous-intensity aerobic physical activity, or an equivalent combination of both spread throughout the week. The recommendation for physical activity to occur in bouts of at least 10 minutes has been eliminated as new research suggests that bouts of any length contribute to the health benefits linked to the accumulated volume of physical activity.
New (July 2011) guidelines in the United Kingdom include the following points:
The intensity at which we exercise is key, and light activity such as strolling and housework is unlikely to have much positive impact on the health of most people. For aerobic exercise to be beneficial, it must raise the heart rate and cause perspiration. Everyone should do a minimum of 150 minutes a week of moderate-intensity aerobic exercise, but that really is the minimum for health benefits. If you do so beyond 150 minutes, you will gain even more health benefits.
Sedentary time (time spent not standing, such as when on the toilet or in bed) is bad for everyone’s health, and no amount of exercise can negate the effects of sitting for too long.
These guidelines are now much more in line with those used in the U.S., which also includes recommendations for muscle-building and bone-strengthening activities such as lifting weights and yoga.<https://www.nhs.uk/news/lifestyle-and-exercise/major-new-exercise-guidelines-announced/>
The U.S. guidelines continue: Additional health benefits may be achieved by engaging in more than 300 minutes (5 hours) of moderate-intensity physical activity per week. Adults should also do muscle-strengthening activities that are of moderate or greater intensity and involve all major muscle groups on two or more days a week, as these activities provide additional health benefits.
Cardiorespiratory fitness can be measured using VO2 max, a measure of the amount of oxygen the body can uptake and utilize. Aerobic exercise, which improves cardiorespiratory fitness, involves movement that increases the heart rate to improve the body’s oxygen consumption. This form of exercise is an important part of all training regiments ranging from professional athletes to the everyday person. Also, it helps increase stamina.
- Jogging – Running at a steady and gentle pace. This form of exercise is great for maintaining weight.
- Elliptical training – This is a stationary exercise machine used to perform walking, or running without causing excessive stress on the joints. This form of exercise is perfect for people with achy hips, knees, and ankles.
- Walking – Moving at a fairly regular pace for a short, medium or long distance.
- Treadmill training – Many treadmills have programs set up that offer numerous different workout plans. One effective cardiovascular activity would be to switch between running and walking. Typically warm up first by walking and then switch off between walking for three minutes and running for three minutes.
- Swimming – Using the arms and legs to keep oneself afloat and moving either forwards or backward. This is a good full-body exercise for those who are looking to strengthen their core while improving cardiovascular endurance.
- Cycling – Riding a bicycle typically involves longer distances than walking or jogging. This is another low-impact exercise on the joints and is great for improving leg strength.
Anaerobic exercise features high-intensity movements performed in a short period of time. It is a fast, high-intensity exercise that doesn’t require the body to utilize oxygen to produce energy. It helps to promote strength, endurance, speed, and power; and is used by bodybuilders to build workout intensity. Thought to increase the metabolic rate which, allows you to burn additional calories as the body recovers from exercise due to an increase in body temperature and excess post-exercise oxygen consumption (EPOC) after the exercise ended.
- Weight lifting – A common type of strength training for developing the strength and size of skeletal muscles.
- Isometric exercise – Helps to maintain strength. A muscle action in which no visible movement occurs and the resistance matches the muscular tension.
- Sprinting – Running short distances as fast as possible
- Interval training – alternating short bursts (lasting around 30 seconds) of intense activity with longer intervals (three to four minutes) of less intense activity.
Specific or task-oriented fitness is a person’s ability to perform in a specific activity with a reasonable efficiency: for example, sports or military service. Specific training prepares athletes to perform well in their sport.
- 100 m sprint: in a sprint, the athlete must be trained to work anaerobically throughout the race, an example of how to do this would be interval training.
- Century Ride: cyclists must be prepared aerobically for a bike ride of 100 miles or more.
- Middle distance running: athletes require both speed and endurance to gain benefit out of this training. The hard-working muscles are at their peak for a longer period of time as they are being used at that level for the longer period of time.
- Marathon: in this case, the athlete must be trained to work aerobically and their endurance must be built-up to a maximum.
- Many firefighters and police officers undergo regular fitness testing to determine if they are capable of the physically demanding tasks required of the job.
- Members of armed forces are often required to pass a formal fitness test. For example, soldiers of the U.S. Army must be able to pass the Army Physical Fitness Test (APFT).
- Hill sprints: requires a high level of fitness to begin with; the exercise is particularly good for the leg muscles. The Army often trains to do mountain climbing and races.
- Plyometric and isometric exercises: An excellent way to build strength and increase muscular endurance.
- Sand running creates less strain on leg muscles than running on grass or concrete. This is because sand collapses beneath the foot, softening the landing. Sand training is an effective way to lose weight and become fit, as more effort is needed (one and a half times more) to run on the soft sand than on a hard surface.
- Aquajogging is a form of exercise that decreases strain on joints and bones. The water supplies minimal impact[clarification needed] to muscles and bones, which is good for those recovering from injury. Furthermore, the resistance of the water as one jogs through it provides an enhanced effect of exercise (the deeper you are the greater the force needed to pull your leg through).
For physical fitness activity to benefit an individual, the exertion triggers a response called a stimulus. Exercise with the correct amount of intensity, duration, and frequency can produce a significant amount of improvement. The person may overall feel better, but the physical effects on the human body take weeks or months to notice and possibly years for full development. For training purposes, exercise must provide a stress or demand on either a function or tissue. To continue improvements, this demand must eventually increase little over an extended period of time. This sort of exercise training has three basic principles: overload, specificity, and progression. These principles are related to health but also enhancement of physical working capacity.
High intensity interval training
High-intensity interval training (HIIT) consists of repeated, short bursts of exercise, completed at a high level of intensity. These sets of intense activity are followed by a predetermined time of rest or low-intensity activity. Studies have shown that exercising at a higher intensity has increased cardiac benefits for humans, compared to when exercising at a low or moderate level. When your workout consists of a HIIT session, your body has to work harder to replace the oxygen it lost. Research into the benefits of HIIT have revealed that it can be very successful for reducing fat, especially around the abdominal region. Furthermore, when compared to continuous moderate exercise, HIIT proves to burn more calories and increase the amount of fat burned post- HIIT session. Lack of time is one of the main reasons stated for not exercising; HIIT is a great alternative for those people because the duration of a HIIT session can be as short as 10 minutes, making it much quicker than conventional workouts.
Controlling blood pressure
Physical fitness has proven to result in positive effects on the body’s blood pressure because staying active and exercising regularly builds up a stronger heart. The heart is the main organ in charge of systolic blood pressure and diastolic blood pressure. Engaging in a physical activity raises blood pressure. Once the subject stops the activity, the blood pressure returns to normal. The more physical activity that one engages in, the easier this process becomes, resulting in a more ‘fit’ individual. Through regular physical fitness, the heart does not have to work as hard to create a rise in blood pressure, which lowers the force on the arteries, and lowers the overall blood pressure.
Centers for disease control and prevention provide lifestyle guidelines for maintaining a balanced diet and engaging in physical activity to reduce the risk of disease. The WCRF/ American Institute for Cancer Research (AICR) published a list of recommendations that reflect the evidence they have found through consistency in fitness and dietary factors that directly relate to cancer prevention.
The WCRF/AICR recommendations include the following:
- Be as lean as possible without becoming underweight.
- Each week, adults should engage in at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity.
- Children should engage in at least one hour of moderate or vigorous physical activity each week.
- Be physically active for at least thirty minutes every day.
- Avoid sugar, and limit the consumption of energy-packed foods.
- Balance one’s diet with a variety of vegetables, grains, fruits, legumes, etc.
- Limit sodium intake, the consumption of red meats, and the consumption of processed meats.
- Limit alcoholic drinks to two for men and one for women a day.
These recommendations are also widely supported by the American Cancer Society. The guidelines have been evaluated and individuals that have higher guideline adherence scores substantially reduce cancer risk as well as help control a multitude of chronic health problems. Regular physical activity is a factor that helps reduce an individual’s blood pressure and improves cholesterol levels, two key components that correlate with heart disease and Type 2 Diabetes. The American Cancer Society encourages the public to “adopt a physically active lifestyle” by meeting the criteria in a variety of physical activities such as hiking, swimming, circuit training, resistance training, lifting, etc. It is understood that cancer is not a disease that can be cured by physical fitness alone, however, because it is a multifactorial disease, physical fitness is a controllable prevention. The large associations tied with being physically fit and reduced cancer risk are enough to provide a strategy to reduce cancer risk.
The American Cancer Society asserts different levels of activity ranging from moderate to vigorous to clarify the recommended time spent on a physical activity. These classifications of physical activity consider intentional exercise and basic activities performed on a daily basis and give the public a greater understanding of what fitness levels suffice as future disease prevention.
Studies have shown an association between increased physical activity and reduced inflammation. It produces both a short-term inflammatory response and a long-term anti-inflammatory effect. Physical activity reduces inflammation in conjunction with or independent of changes in body weight. However, the mechanisms linking physical activity to inflammation are unknown.
Physical activity boosts the immune system. This is dependent on the concentration of endogenous factors (such as sex hormones, metabolic hormones and growth hormones), body temperature, blood flow, hydration status and body position. Physical activity has shown to increase the levels of natural killer (NK) cells, NK T cells, macrophages, neutrophils and eosinophils, complements, cytokines, antibodies and T cytotoxic cells. However, the mechanism linking physical activity to immune system is not fully understood.
Achieving resilience through physical fitness promotes a vast and complex range of health-related benefits. Individuals who keep up physical fitness levels generally regulate their distribution of body fat and prevent obesity. Abdominal fat, specifically visceral fat, is most directly affected by engaging in aerobic exercise. Strength training has been known to increase the amount of muscle in the body, however, it can also reduce body fat. Sex steroid hormones, insulin, and appropriate immune responses are factors that mediate metabolism in relation to abdominal fat. Therefore, physical fitness provides weight control through regulation of these bodily functions.
Menopause and physical fitness
Menopause is often said to have occurred when a woman has had no vaginal bleeding for over a year since her last menstrual cycle. There are a number of symptoms connected to menopause, most of which can affect the quality of life of a woman involved in this stage of her life. One way to reduce the severity of the symptoms is to exercise and keep a healthy level of fitness. Prior to and during menopause, as the female body changes, there can be physical, physiological or internal changes to the body. These changes can be reduced or even prevented with regular exercise. These changes include:
- Preventing weight gain: around menopause women tend to experience a reduction in muscle mass and an increase in fat levels. Increasing the amount of physical exercise undertaken can help to prevent these changes.
- Reducing the risk of breast cancer: weight loss from regular exercise may offer protection from breast cancer.
- Strengthening bones: physical activity can slow the bone loss associated with menopause, reducing the chance of bone fractures and osteoporosis.
- Reducing the risk of disease: excess weight can increase the risk of heart disease and type 2 diabetes, and regular physical activity can counter these effects.
- Boosting mood: being involved in regular activities can improve psychological health, an effect that can be seen at any age and not just during or after menopause.
The Melbourne Women’s Midlife Health Project followed 438 women over an eight-year period providing evidence showing that even though physical activity was not associated with VMS in this cohort at the beginning, Women who reported they were physically active every day at the beginning were 49% less likely to have reported bothersome hot flushes. This is in contrast to women whose level of activity decreased and were more likely to experience bothersome hot flushes.
Studies have shown that physical activity can improve mental health and well-being. This improvement is due to an increase in blood flow to the brain and the release of hormones. Being physically fit and working out on a consistent basis can positively impact one’s mental health and bring about several other benefits, such as the following.
- Physical activity has been linked to the alleviation of depression and anxiety symptoms.
- In patients suffering from schizophrenia, physical fitness has been shown to improve their quality of life and decrease the effects of schizophrenia.
- Being fit can improve one’s self-esteem.
- Working out can improve one’s mental alertness and it can reduce fatigue.
- Studies have shown a reduction in stress levels.
- Increased opportunity for social interaction, allowing for improved social skills
To achieve some of these benefits, the Centers for Disease Control and Prevention suggests at least 30–60 minutes of exercise 3-5 times a week.
Physical fitness has always been an important part of life. It is theorized that when people left a hunter-gatherer lifestyle and formed fixed communities based around agriculture that physical fitness levels declined. This is not to say that levels of physical labor decreased but that the type of work undertaken was not necessarily as conducive to a general level of fitness. As such, regimented fitness regimes were either invented or became more common. This was especially the case in classical civilizations such as Ancient Greece and Rome. In Greece, physical fitness was considered to be an essential component of a healthy life and it was the norm for men to frequent a gymnasium. Physical fitness regimes were also considered to be of paramount importance in a nation’s ability to train soldiers for an effective military force. Partly for these reasons, organized fitness regimes have been in existence throughout known history and evidence of them can be found in many countries.
Gymnasiums which would seem familiar today began to become increasingly common in the 19th century. The industrial revolution had led to a more sedentary lifestyle for many people and there was an increased awareness that this had the potential to be harmful to health. This was a key motivating factor for the forming of a physical culture movement, especially in Europe and the USA. This movement advocated increased levels of physical fitness for men, women, and children and sought to do so through various forms of indoor and outdoor activity, and education. In many ways, it laid the foundations for modern fitness culture.
- Tremblay MS, Colley RC, Saunders TJ, Healy GN, Owen N (December 2010). “Physiological and health implications of a sedentary lifestyle”. Applied Physiology, Nutrition, and Metabolism. 35 (6): 725–40. doi:10.1139/H10-079. PMID 21164543.
- de Groot GC, Fagerström L (June 2011). “Older adults’ motivating factors and barriers to exercise to prevent falls”. Scandinavian Journal of Occupational Therapy. 18 (2): 153–60. doi:10.3109/11038128.2010.487113. PMID 20545467.
- Malina R (2010). Physical activity and health of youth. Constanta: Ovidius University Annals, Series Physical Education and Sport/Science, Movement and Health.
- “President’s Council on Physical Fitness and Sports Definitions for Health, Fitness, and Physical Activity”. fitness.gov. Archived from the original on 12 July 2012.
- “Merriam-Webster Dictionary”.
- “Google Ngram Viewer”. Google.
- Colfer GR (19 January 2004). “Skill-related physical fitness essential for sports success”. tradoc.army.mil. Archived from the original on June 2011.
- Nied RJ, Franklin B (February 2002). “Promoting and prescribing exercise for the elderly”. American Family Physician. 65 (3): 419–26. PMID 11858624.
- “Exercise for Your Bone Health”. nih.gov.
- “Participation in Sport and Physical Recreation, Australia”. Australian Bureau of Statistics. 18 February 2015.
- “Physical Activity Fundamental To Preventing Disease”. U.S. Department of Health & Human Services. 20 June 2002.
- “How much physical activity do adults need?”. Centers for Disease Control and Prevention. 1 December 2011. Retrieved 29 April 2013.
- Pedersen BK, Febbraio MA (April 2012). “Muscles, exercise, and obesity: skeletal muscle as a secretory organ”. Nature Reviews. Endocrinology. 8 (8): 457–65. doi:10.1038/nrendo.2012.49. PMID 22473333.
- “Physical Activity Guidelines for Americans 2nd edition” (PDF). U.S. Department of Health and Human Services. 2018.
- Haskell WL, Troiano RP, Hammond JA, Phillips MJ, Strader LC, Marquez DX, Grant SF, Ramos E (May 2012). “Physical activity and physical fitness: standardizing assessment with the PhenX Toolkit”. American Journal of Preventive Medicine. 42 (5): 486–92. doi:10.1016/j.amepre.2011.11.017. PMC 3331998. PMID 22516489.
- Chakravertty B, Parkavi K, Coumary SA, Felix AJ (April 2012). “Antepartum cardiorespiratory fitness (CRF) quantification by estimation of maximal oxygen consumption (Vo2 max) in pregnant South Indian women”. Journal of the Indian Medical Association. 110 (4): 214–7. PMID 23025219.CS1 maint: uses authors parameter (link)
- Osawa Y, Azuma K, Tabata S, Katsukawa F, Ishida H, Oguma Y, Kawai T, Itoh H, Okuda S, Matsumoto H (2014). “Effects of 16-week high-intensity interval training using upper and lower body ergometers on aerobic fitness and morphological changes in healthy men: a preliminary study”. Open Access Journal of Sports Medicine. 5: 257–65. doi:10.2147/OAJSM.S68932. PMC 4226445. PMID 25395872.
- Mackenzie B (2001). “Middle Distance Running”. Middle Distance Running. BrianMac Sports Coach.CS1 maint: uses authors parameter (link)
- “Training: Physical Fitness Program”. sccfd.org.
- “Enlist : Army Physical Fitness Test”. Army.com. Archived from the original on 6 January 2010.
- “Running on the Beach: The Benefits & Dangers”. Runners Feed. Archived from the original on 1 September 2015. Retrieved 14 April 2015.
- Harriman D (28 January 2015). “Aqua Jogging for Runners”. livestrong.com.
- Swimming Anatomy. Human Kinetics. 2010. p. 147. ISBN 9781450409179.
- Blair SN (December 1993). “1993 C.H. McCloy Research Lecture: physical activity, physical fitness, and health”. Research Quarterly for Exercise and Sport. 64 (4): 365–76. doi:10.1080/02701367.1993.10607589. PMID 8278662.CS1 maint: uses authors parameter (link)
- Wisløff U, Ellingsen Ø, Kemi OJ (July 2009). “High-intensity interval training to maximize cardiac benefits of exercise training?”. Exercise and Sport Sciences Reviews. 37 (3): 139–46. doi:10.1097/JES.0b013e3181aa65fc. PMID 19550205.
- Gillen JB, Gibala MJ (March 2014). “Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?”. Applied Physiology, Nutrition, and Metabolism. 39 (3): 409–12. doi:10.1139/apnm-2013-0187. PMID 24552392.
- “Eight weeks of a combination of high-intensity interval training and conventional training reduce visceral adiposity and improve physical fitness: a group-based intervention”. minervamedica. April 2016.
- Shiraev T, Barclay G (December 2012). “Evidence based exercise – clinical benefits of high-intensity interval training”. Australian Family Physician. 41 (12): 960–2. PMID 23210120.
- Whitehurst M (2012). “High-intensity interval training: An alternative for older adults”. American Journal of Lifestyle Medicine. 6 (5): 382–386. doi:10.1177/1559827612450262.
- “Exercise: A Drug-free Approach to Lowering High Blood Pressure”. mayoclinic.org.
- “Blood Pressure : Exercise & Activity Lower Blood Pressure”. bloodpressureuk.org.
- Alberts, David S. and Hess, Lisa M. (2005). Fundamentals of Cancer Prevention. Berlin: Springer, ISBN 364238983X.
- U.S. Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1996.
- Colbert LH, Visser M, Simonsick EM, Tracy RP, Newman AB, Kritchevsky SB, Pahor M, Taaffe DR, Brach J, Rubin S, Harris TB (July 2004). “Physical activity, exercise, and inflammatory markers in older adults: findings from the Health, Aging and Body Composition Study”. Journal of the American Geriatrics Society. 52 (7): 1098–104. doi:10.1111/j.1532-5415.2004.52307.x. PMID 15209647.
- Kasapis C, Thompson PD (May 2005). “The effects of physical activity on serum C-reactive protein and inflammatory markers: a systematic review”. Journal of the American College of Cardiology. 45 (10): 1563–9. doi:10.1016/j.jacc.2004.12.077. PMID 15893167.
- Campbell KL, McTiernan A (January 2007). “Exercise and biomarkers for cancer prevention studies”. The Journal of Nutrition. 137 (1 Suppl): 161S–169S. doi:10.1093/jn/137.1.161S. PMID 17182820.
- Nieman DC (March 1997). “Exercise immunology: practical applications”. International Journal of Sports Medicine. 18 Suppl 1: S91–100. doi:10.1055/s-2007-972705. PMID 9129268.
- Fairey AS, Courneya KS, Field CJ, Mackey JR (January 2002). “Physical exercise and immune system function in cancer survivors: a comprehensive review and future directions”. Cancer. 94 (2): 539–51. doi:10.1002/cncr.10244. PMID 11900239.
- Kruijsen-Jaarsma M, Révész D, Bierings MB, Buffart LM, Takken T (1 January 2013). “Effects of exercise on immune function in patients with cancer: a systematic review”. Exercise Immunology Review. 19: 120–43. PMID 23977724.
- Westcott WL, La Rosa Loud R (2014). “Strength for fat loss training”. American Fitness. 32 (1): 18–22.
- Westerlind KC (November 2003). “Physical activity and cancer prevention–mechanisms”. Medicine and Science in Sports and Exercise. 35 (11): 1834–40. doi:10.1249/01.MSS.0000093619.37805.B7. PMID 14600547.CS1 maint: uses authors parameter (link)
- Sternfeld B, Dugan S (September 2011). “Physical activity and health during the menopausal transition”. Obstetrics and Gynecology Clinics of North America. 38 (3): 537–66. doi:10.1016/j.ogc.2011.05.008. PMC 3270074. PMID 21961719.CS1 maint: uses authors parameter (link)
- Pruthi S (June 2013). “Fitness Tips for Menopause: Why fitness counts”. Mayo Clinic. Retrieved 11 April 2015.
- Eschbach C (12 January 2012). “Exercise Recommendations for Menopause-Aged Women”. American College of Sports Medicine. American College of Sports Medicine. Retrieved 12 April 2015.
- Callaghan P (August 2004). “Exercise: a neglected intervention in mental health care?”. Journal of Psychiatric and Mental Health Nursing. 11 (4): 476–83. doi:10.1111/j.1365-2850.2004.00751.x. PMID 15255923.
- “Physical activity and mental health”. 7 August 2015.
- Sharma A, Madaan V, Petty FD (2006). “Exercise for mental health”. Primary Care Companion to the Journal of Clinical Psychiatry. 8 (2): 106. doi:10.4088/PCC.v08n0208a. PMC 1470658. PMID 16862239.
- Vancampfort D, Probst M, Scheewe T, De Herdt A, Sweers K, Knapen J, van Winkel R, De Hert M (May 2013). “Relationships between physical fitness, physical activity, smoking and metabolic and mental health parameters in people with schizophrenia”. Psychiatry Research. 207 (1–2): 25–32. doi:10.1016/j.psychres.2012.09.026. PMID 23051886.CS1 maint: uses authors parameter (link)
- “Benefits of Physical Activity”. Centers for Disease Control and Prevention. 6 March 2018. Retrieved 30 April 2018.
- “Benefits of Physical Fitness Wear”. Centers for Disease Control and Prevention. 6 March 2018. Retrieved 30 April 2018.
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