Exercise
[19] The majority of the benefits from exercise are achieved with around 3500 metabolic equivalent (MET) minutes per week, with diminishing returns at higher levels of activity.
[21] The American-British writer Bill Bryson wrote: "If someone invented a pill that could do for us all that a moderate amount of exercise achieves, it would instantly become the most successful drug in history.
Children who are more proficient with motor skills early on are more inclined to be physically active, and thus tend to perform well in sports and have better fitness levels.
[30][31] Children who participate in physical exercise experience greater loss of body fat and increased cardiovascular fitness.
Immune cell functions are impaired following acute sessions of prolonged, high-intensity exercise, and some studies have found that athletes are at a higher risk for infections.
Studies have shown that strenuous stress for long durations, such as training for a marathon, can suppress the immune system by decreasing the concentration of lymphocytes.
In individuals with heart disease, exercise interventions lower blood levels of fibrinogen and C-reactive protein, an important cardiovascular risk marker.
According to the review, "[there] was consistent evidence from 27 observational studies that physical activity is associated with reduced all-cause, breast cancer–specific, and colon cancer–specific mortality.
"[39] Evidence suggests that exercise may positively affect the quality of life in cancer survivors, including factors such as anxiety, self-esteem and emotional well-being.
[40] For people with cancer undergoing active treatment, exercise may also have positive effects on health-related quality of life, such as fatigue and physical functioning.
[44][45] There is low-quality evidence for an effect of aerobic physical exercises on anxiety and serious adverse events in adults with hematological malignancies.
[58] Aerobic exercise may affect both self-esteem and overall well-being (including sleep patterns) with consistent, long term participation.
[55][62][63][64] The American Academy of Neurology's clinical practice guideline for mild cognitive impairment indicates that clinicians should recommend regular exercise (two times per week) to individuals who have been diagnosed with these conditions.
The 2013 Cochrane Collaboration review on physical exercise for depression noted that, based upon limited evidence, it is more effective than a control intervention and comparable to psychological or antidepressant drug therapies.
[76] Another review asserted that evidence from clinical trials supports the efficacy of physical exercise as a treatment for depression over a 2–4 month period.
[51] These benefits have also been noted in old age, with a review conducted in 2019 finding that exercise is an effective treatment for clinically diagnosed depression in older adults.
[80][81][82] Supervised aerobic exercise without a risk of re-injury (falling, getting hit on the head) is prescribed as treatment for acute concussion.
[84] Preliminary evidence from a 2012 review indicated that physical training for up to four months may increase sleep quality in adults over 40 years of age.
[medical citation needed] There is some level of concern about additional exposure to air pollution when exercising outdoors, especially near traffic.
[96][90][97] These effects occur via an exercise-induced increase in the intracellular AMP:ATP ratio, thereby triggering the activation of AMP-activated protein kinase (AMPK) which subsequently phosphorylates peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), the master regulator of mitochondrial biogenesis.
The effects of physical exercise on the central nervous system may be mediated in part by specific neurotrophic factor hormones released into the blood by muscles, including BDNF, IGF-1, and VEGF.
[122] The city of Bogotá, Colombia, for example, blocks off 113 kilometers (70 mi) of roads on Sundays and holidays to make it easier for its citizens to get exercise.
[124] According to the Centers for Disease Control and Prevention in the United States, children and adolescents should do 60 minutes or more of physical activity each day.
[125] Implementing physical exercise in the school system and ensuring an environment in which children can reduce barriers to maintain a healthy lifestyle is essential.
[127] This has been accompanied by increasing use of mechanized transportation, a greater prevalence of labor-saving technology in the home, and fewer active recreational pursuits.
In Bogotá, Colombia, a 70-mile stretch of road known as the Ciclovía is shut down each Sunday for bicyclists, runners, rollerbladers, skateboarders and other exercisers to work out and enjoy their surroundings.
Dating back to 65 BCE, it was Marcus Cicero, Roman politician and lawyer, who stated: "It is exercise alone that supports the spirits, and keeps the mind in vigor.
"[147] Exercise was also seen to be valued later in history during the Early Middle Ages as a means of survival by the Germanic peoples of Northern Europe.
In 1858, Archibald MacLaren opened a gymnasium at the University of Oxford and instituted a training regimen for Major Frederick Hammersley and 12 non-commissioned officers.
[158] Artificial selection of mice exhibited significant heritability in voluntary exercise levels,[159] with "high-runner" breeds having enhanced aerobic capacity,[160] hippocampal neurogenesis,[161] and skeletal muscle morphology.
