Benefits of Exercise
Abundant evidence supports the anti-aging benefits of exercise. Even a modest amount of leisure time physical activity—just 75 minutes of brisk walking per week—has been associated with longer life expectancy (Moore 2012). Also, regular exercise correlated with independence in a study of Japanese centenarians (Ozaki 2007).
Exercise influences several hallmarks of aging, including DNA repair, cellular senescence, and mitochondrial function (Garatachea 2015). Resistance exercise decreases oxidative DNA damage in aging individuals (Parise 2005) and increases mitochondrial biogenesis—the creation of new mitochondria—in muscle and brain tissue (Steiner 2011; Garatachea 2015).
Exercise can help prevent cardiovascular disease during aging, and helps stave off sarcopenia, or age-related loss of muscle mass and strength (Avin 2014; Landi 2014). Improvements in muscle strength resulting from resistance exercise can increase functional capacity and reduce risk of disease and disability in old age (Manini 2009). Physical activity, especially resistance strength training, also helps maintain healthy bone density during aging (Howe 2011).
Exercise also powerfully activates another major longevity factor called adenosine monophosphate-activated protein kinase (AMPK)—a key regulator of energy metabolism (O'Neill 2013). AMPK is an enzyme that, when activated, promotes the burning of glucose and fats to generate cellular energy. AMPK also inhibits aberrant cell growth (ie, cancer), promotes the creation of new mitochondria, and increases insulin sensitivity (O'Neill 2013; Richter 2009; Vincent 2015).
AMPK activation may be responsible for many of the health benefits of exercise; conversely, lack of AMPK activation may contribute to the detrimental health effects of a sedentary lifestyle (O'Neill 2013; Richter 2009).
The antidiabetic agent metformin also activates AMPK and may mitigate other chronic diseases linked to inactivity, such as heart disease and cancer (Richter 2009; Barzilai 2016; Anisimov 2013).
Preclinical evidence suggests the magnitude of AMPK activation in response to exercise diminishes with age (Reznick 2007). Therefore, AMPK-activating agents such as metformin and the plant extract Gynostemma pentaphyllum may offer complementary benefits alongside exercise in aging adults.
Protecting Against Immune Senescence
The progressive deterioration of the immune system that occurs with aging is termed immune senescence. Immune senescence is associated with poor response to vaccinations and increased risk of infection, cancer, cardiovascular disease, diabetes, and other age-related chronic diseases (Turner 2016; Goronzy 2013; Maijo 2014).
Emerging evidence indicates regular exercise protects against immune senescence and may rejuvenate the aging immune system (Turner 2016; Simpson 2015; Simpson 2014). In a study in healthy male subjects, those with better cardiorespiratory fitness had lower age-related accumulation of senescent and nonfunctional T cells—a signature feature of immune senescence (Spielmann 2011).
Human and animal studies have shown that regular exercise favorably affects other markers of immune senescence as well. These include enhanced vaccination responses, lower blood levels of inflammatory cytokines, greater natural killer (NK) cell activity, and better outcomes in viral infections and some cancers (Simpson 2012).
Moderate-to-high intensity exercise (ie, 50% to 70% of maximal oxygen consumption) performed on a regular basis (eg, 30 minutes, five days per week) enhances immune function and lowers the incidence of chronic disease (Turner 2016; Simpson 2014; Brown 2015).
Exercise improves several cardiovascular risk parameters including blood pressure, inflammation, glucose and insulin metabolism, endothelial function, cerebral blood flow, and blood lipids (Eijsvogels 2016; Wang 2015b).
Exercise is also beneficial in the treatment of existing cardiovascular diseases (Wang 2015b; Hegde 2015). According to a review of 63 randomized controlled trials that enrolled nearly 15,000 patients with established coronary heart disease, exercise-based cardiac rehabilitation programs reduced mortality and hospitalizations due to heart disease. In the majority of these studies, exercise also improved patient quality of life (Anderson 2016).
Note: Individuals with pre-existing cardiovascular disease should consult a qualified healthcare provider before embarking on an exercise program.
Physical activity can prevent cognitive decline in older adults and reduce the risk of neurological diseases such as Alzheimer disease and Parkinson disease. Aerobic exercise has also reduced the loss of brain tissue that occurs with aging (Gomez-Pinilla 2013; Bherer 2013; Kelly 2014; Tse 2015; Colcombe 2003).
Abundant evidence indicates physical activity and exercise enhance cognitive health throughout life (Gomez-Pinilla 2013; Tolppanen 2015; Zhu 2014). In a study in 2747 young adults aged 18‒30 years, greater aerobic fitness was associated with better verbal memory and faster psychomotor speed in middle age (Zhu 2014). Similarly, another study found middle-aged participants who engaged in the most leisure time physical activity were less likely to develop dementia 28 years later compared with less-active participants (Tolppanen 2015).
Exercise improves cognitive health by enhancing the transmission of information between nerve cells. Brain-derived neurotrophic factor, a signaling protein, appears to play a critical role in this process. Exercise increases the production of brain-derived neurotrophic factor in an area of the brain called the hippocampus, which is vital to learning and memory. Intriguingly, exercise may even increase the size of the hippocampus (Gomez-Pinilla 2013; Bherer 2013).
According to recommendations from the American Heart Association and American College of Cardiology, long-term weight loss is best attained with lifestyle change that includes both a low-calorie diet and increased physical activity (Higgins 2016; Bray 2016).
Protection Against Diabetes
Exercise increases insulin sensitivity, helps control blood glucose levels, and improves cardiovascular risk factors such as high blood pressure and elevated blood fats. Even a single exercise session has induced many of these beneficial effects (Stanford 2014; Colberg 2010; Asano 2014).
Randomized trials have shown that combining physical activity with modest weight loss lowers type 2 diabetes risk by up to 58% in high-risk populations (Stanford 2014; Colberg 2010). In a four-year randomized controlled lifestyle-intervention trial, increased physical activity along with reduced caloric intake resulted in partial or complete remission of diabetes in 11.5% of participants during the first year; 7.3% of participants remained in partial or complete remission after four years (Gregg 2012).
Chronic Pain Management
A detailed analysis of 264 published studies, which included nearly 20,000 participants, found that exercise and physical activity is associated with modest improvements in pain, functional capacity, and quality of life. Another review of published studies found that high-intensity strength exercises performed in the workplace three times weekly for 20 minutes markedly reduced pain in the shoulders and spine (Rodrigues 2014). In a separate analysis, supervised and home-based progressive shoulder strengthening and stretching exercises relieved shoulder pain. For low-grade shoulder pain, exercise provided short-term benefits similar in magnitude to a single steroid injection (Abdulla 2015).
Preventing Functional Decline with Age: Sarcopenia and Osteoporosis
Sarcopenia refers to progressive loss of muscle mass and strength with age. Osteoporosis is a condition marked by low bone mass, increased bone fragility, and greater fracture risk. Sarcopenia and osteoporosis share similarities: both are common in older adults, both increase risk of falls and fractures, and both are linked to frailty, decreased mobility, and a higher risk of death (Edwards 2015; Blain 2014; Avin 2014; Cruz-Jentoft 2010; He 2016; Go 2013; Kim 2014; Reginster 2016).
Physical activity and exercise training, including aerobic activity and strength training, increase bone mass, muscular strength, balance, and mobility (Shanb 2014; Beck 2016; Castrogiovanni 2016). A review of the scientific literature found regular physical activity is the only intervention that consistently improves frailty and sarcopenia as well as functional performance in older adults (Landi 2014).
Improvements in physical function resulting from exercise have been demonstrated even in the frail elderly, including those living in institutional settings (Weening-Dijksterhuis 2011; Chin 2008). A regular program of both aerobic and strength exercise is recommended for adults as well as frail older persons (Landi 2014).
Gut Microbiome Modulation
Microbes in the gastrointestinal tract play a critical role in human health. Increased microbial diversity has been associated with improved metabolism, immune function, and overall health. Disturbances to the balance of these microbes, including reduced diversity of the gut microbiome, have been linked to a wide range of diseases including obesity, metabolic syndrome, and inflammatory bowel disease (Cerda 2016; Robles Alonso 2013; Clarke 2014; Bermon 2015).
While a range of factors, such as diet and antibiotic usage, influence the gut microbiome, early evidence suggests exercise may have a positive influence (Cerda 2016). In one study, professional athletes had a significantly higher diversity of gut microorganisms than control groups. Dietary differences between the athletes and control groups may have accounted for some of these effects (Clarke 2014; O'Sullivan 2015).
A study in mice found exercise altered gut microbial composition, improved intestinal structural integrity, and reduced gastrointestinal inflammation (Campbell 2016). In another study in mice, exercise increased abundance and diversity of the gut microbiome and protected against a toxin-induced reduction in microbial abundance (Choi 2013).