Fitness May be the Key to Longevity
Introdcution
Often when we hear of exercise, it is often discussed in terms of vanity such as weight loss or promotion or the general idea of just feeling better. What is often missing is stressing just how important exercise is to every aspect of our health and wellbeing. Not only is exercise important for our general health, but it may also change the very trajectory of our experience when aging. This paper will discuss the literature on longevity and how regular exercise can benefit us.
Exercise can be broken down into four main categories: strength training, cardiovascular training (aerobic and anaerobic), balance and coordination training, and stretching (Gremeaux, 2012). For the most part this paper will focus on strength (resistance) training and cardiovascular training as they are the most regularly studied.
Each of these types of exercise components have different functionalities but are all incredibly important towards the function of our bodies, especially as we age. Strength training is important for protecting our joints from injury, reducing risks of falls, and maintaining or improving strength for everyday activities. Cardiovascular training improves our cardiovascular health, protecting us from the risks of stroke, heart disease, high blood pressure, and can improve our cognitive functioning. Balance and coordination training improves our proprioception, protecting us from the risks of falls and injury as we better understand where our body is in relation to our environment. Stretching keeps our muscles flexible, preventing tears and injury as well as preventing us from favoring one side of our body which can disrupt the kinetic chain causing compounding injuries over time.
As we age our body naturally changes, becomes less efficient with changes in metabolism, decreases in lean muscle mass (sarcopenia), cardiovascular changes and more. Exercise can have a protective effect on these systems and many more such as our neurological and skeletal health. The importance of regular and consistent exercise cannot be overstated. Short of overdoing the amount of exercise you do in a day; exercise has positive effects in nearly every aspect of health and aging one can think of.
Studies show that maintaining the minimal quantity and quality of exercising can preserve functional aging and partially reverse the effects of aging, protecting against the risks of death, development of certain types of cancer, and increasing longevity (Gremeaux, 2012). Successful aging requires a maintenance of our physical and mental well-being. This allows us to remain functionally independent. Regular exercise is one of the best preventative approaches toward successful aging (Gremeaux, 2012). According to Gremeaux, et al. (2012), meta-analyses on the effects of aging and mortality showed a 30% reduction of both all-cause mortality and cardiovascular mortality. With better tools for metric tracking coming from improvements in technology, such as step counters, we can see how physical activity in real world settings can improve health. A study in Japan showed that elderly adults walking over 8000 steps per day had better physical health, and those that walked over 4000 steps a day had better mental health (Aoyagi, 2010).
Exercise and Aging - An Overview
Studies show that maintaining the minimal quantity and quality of exercising can preserve functional aging and partially reverse the effects of aging, protecting against the risks of death, development of certain types of cancer, and increasing longevity (Gremeaux, 2012). Successful aging requires a maintenance of our physical and mental well-being. This allows us to remain functionally independent. Regular exercise is one of the best preventative approaches toward successful aging (Gremeaux, 2012).
According to Gremeaux, et al. (2012), meta-analyses on the effects of aging and mortality showed a 30% reduction of both all-cause mortality and cardiovascular mortality. With better tools for metric tracking coming from improvements in technology, such as step counters, we can see how physical activity in real world settings can improve health. A study in Japan showed that elderly adults walking over 8000 steps per day had better physical health, and those that walked over 4000 steps a day had better mental health (Aoyagi, 2010).
Exercise is regularly shown to have protective effects reducing the risks of type 2 diabetes, cardiovascular risks, strokes, hypertension, fall risks, osteoporosis, cancers, depression and more. There has even been links to physical activity and delays in signs of dementia or other cognitive conditions (Gremeaux, 2012). Regular aerobic activity can be one of the strongest predicters of all-cause mortality and health status in older adults. Aerobic exercises can include walking, swimming, biking, or some other exercise that requires steady movement for a period longer than 2 minutes. Regular exercise can improve VO2max which are instrumental in maintaining activities of daily living unaided (Gremeaux, 2012). Regular strength training exercise can increase muscle mass and force produced by a muscle group reducing strength decline and functionality deficits in older adults (Gremeaux, 2012). This mechanical loading can also increase bone mass and mineral density lowering the risks of osteoporosis, though the exact effects are hard to parse out due to confounding factors such as medication, dietary effects, and genetics (Gremeaux, 2012). Exercise has many benefits to different aspects of age-related decline.
Exercise can Improve Your Balance
Balance training is an important factor towards longevity, reducing the risk of fall which is one of the highest causes of accidental death in the senior population. According to Thomas, et al. (2019), “over 30% of people aged 65 or older…experience on average 1 fall a year.” Eight studies included in a quantitative synthesis showed that aerobic exercise interventions demonstrated an increased positive in balance measures. Resistance protocols also indicated an improvement in balance measures but were not as effective as multicomponent exercise interventions.
Interestingly balance training using static and dynamic balance exercises saw not only an increase in balance measures, but also saw an increase in aerobic capacity (Thomas, 2019). Resistance exercise programs saw 25% balance ability improvement over baseline and aerobic exercise programs saw a 31% balance increase over baseline (Thomas, 2019).
Physical Fitness can Effect Alzheimer’s, Dementia, Cognition, and Mental Health
Beyond the effects on the musculature and heart health, physical activity can also help protect against neurodegenerative disorders. One study has potentially linked exercise to protective effects against Parkinson’s disease. Alpha-synuclein (αS) is a major component of Lewy bodies, which can be found in multiple diseases from Parkinson’s disease to dementia with Lewy bodies. On their own αS are not problematic and they can be important in maintaining synaptic functioning, however, when the protein misfolds and clumps it kills dopamine-producing cells in the brain which is a key trigger to Parkinson’s disease (Wasta, 2022). According to Wasta (2022), periods of high endurance and aerobic exercise produces a hormone irisin. In a study done on mice, researchers injected alpha-synuclein into the striatum of the mouse brain. This produced Parkinson’s like symptoms in the mice. Later the researchers injected a viral vector to increase the blood levels of irisin in the mice. Six months later the mice showed no muscular movement deficits (Wasta, 2022). This led the researchers to believe that regular aerobic exercise can have a protective effect on developing Parkinson’s.
Beyond the effects on the musculature and heart health, physical activity can also help protect against neurodegenerative disorders. One study has potentially linked exercise to protective effects against Parkinson’s disease. Alpha-synuclein (αS) is a major component of Lewy bodies, which can be found in multiple diseases from Parkinson’s disease to dementia with Lewy bodies.
On their own αS are not problematic and they can be important in maintaining synaptic functioning, however, when the protein misfolds and clumps it kills dopamine-producing cells in the brain which is a key trigger to Parkinson’s disease (Wasta, 2022).
According to Wasta (2022), periods of high endurance and aerobic exercise produces a hormone irisin. In a study done on mice, researchers injected alpha-synuclein into the striatum of the mouse brain. This produced Parkinson’s like symptoms in the mice. Later the researchers injected a viral vector to increase the blood levels of irisin in the mice. Six months later the mice showed no muscular movement deficits (Wasta, 2022). This led the researchers to believe that regular aerobic exercise can have a protective effect on developing Parkinson’s.
Aerobic exercise is regularly studied and found to offer benefits on cognition. It does not appear that aerobic exercise can reverse cognitive decline, but more so that it has preventative or slowing benefits for cognitive decline by enhancing brain function and structure (Liu-Ambrose, 2009). According to Lui-Ambrose, et al. (2009), “there is evidence to support the hypothesis that resistance training (and balance training) may have cognitive benefits among seniors” and this may be especially important for senior women. Upon conclusion of a 12-month group-based strength and balance training program, senior residents showed improvements in fluid intelligence (Liu-Ambrose, 2009). Having exercise programs that take on cardiovascular as well as resistance training can have a broad range of systemic benefits.
Aerobic exercise is regularly studied and found to offer benefits on cognition. It does not appear that aerobic exercise can reverse cognitive decline, but more so that it has preventative or slowing benefits for cognitive decline by enhancing brain function and structure (Liu-Ambrose, 2009). According to Lui-Ambrose, et al. (2009), “there is evidence to support the hypothesis that resistance training (and balance training) may have cognitive benefits among seniors” and this may be especially important for senior women. Upon conclusion of a 12-month group-based strength and balance training program, senior residents showed improvements in fluid intelligence (Liu-Ambrose, 2009). Having exercise programs that take on cardiovascular as well as resistance training can have a broad range of systemic benefits.
According to DiLiegro, et al. (2019) physical activity has a positive effect on mental health but there is no clear indication on the type, intensity, and frequency of exercise that leads to the best results for mental health. Cardiovascular exercises can increase neurogenesis of the hippocampus (Di Liegro, 2019). Physical activity has shown to inhibit Alzheimer’s Disease progression. Exercise produces a variety of hormones which reduce inflammation, change insulin production, and use, and stimulate effects on the learning and memory processes (Di Liegro, 2019). Patients with Multiple Sclerosis or MS regularly had better outcomes than those who were sedentary. Physical activity has a neuroprotective effect against different neurodegenerative diseases. Different exercise protocols may benefit certain disease and ailments more than others, and eventually with more study we may find ideal exercise protocols to protect against certain neurodegenerative diseases (Di Liegro, 2019). Those who exercised despite MS reported less incidence of fatigue, depression, and had a better quality of life. Exercise also produces and stimulates the body’s natural opioid, endocannabinoid, analgesia, and endorphin symptoms. These boosts in production of neurotransmitters and neurosteroids have been shown to improve moods and regulate stress responses (Di Liegro, 2019).
Exercise Lowers the Risk of All-Cause Mortality
Higher activity levels are correlated to lower mortality risk and better health in old age. It also is never too late to start a new exercise regimen and it can lead to significant improvements in health and improvements in cognition. Regular exercise can improve peripheral motor neuron control within the legs and reduce the risk of falls, and even if a fall does occur, they are less likely to suffer from a fracture (McPhee, 2016). Older adults who maintained regular jogging regimens were shown to postpone disability by almost 9 years and had three times lower risk of mortality compared to non-runners (McPhee, 2016). According to McPhee, et al. (2016) “The combination of strength and endurance training improved muscle, cardiorespiratory and metabolic health which all contributed to improved quality of life.” In the frail, a 12-month combined exercise regimen (strength, aerobic, balance, and flexibility) improved activity levels and reduced risks of mobility disability by 30% (McPhee, 2016).
Cardiovascular disease is the leading cause of morbidity and mortality worldwide, often linked to poor diet and a sedentary lifestyle. Death rates are shown “to be inversely related to cardiorespiratory fitness levels, even in the presence of other predictors of cardiovascular mortality such as smoking, hypertension, and hyperlipidemia” (Nystoriak, 2018). Better fitness levels can also partially reverse issues with elevated risk of all-cause mortality associated with higher body mass index (Nystoriak, 2018). One study showed regular physical activity can reduce inflammation and rescue aortic valve endothelial integrity in mice with high cholesterol diets.
A single session of low-intensity exercise showed significant improvements on insulin sensitivity and fatty acid uptake the following day. Increased physical activity may control our insulin responses in our cells and lower the risk of type 2 diabetes (Nystoriak, 2018).Exercise has also been shown to lower blood pressure at rest by increasing cardiac stroke volume and heart rate when exercising. Moderate to intense exercises done 3-5 times a week “lowers blood pressure by an average of 3.4/2.4 mmHg” (Nystoriak, 2018). This small reduction can reduce heart failure by 2 to 6 people per every 1000 each year.
Exercise can remodel the metabolic, molecular, and cardiac systems within the body. It can reduce the risk of arrhythmia, improve systolic and diastolic functions, and produce greater force of cardiac contraction (Nystoriak, 2018). Physical activity also creates an adaptive response helping the body use oxygen more efficiently and greater vasodilatory capacity. Together these lower resting heart rate and improve blood pressure.
Diabetes is a common ailment of those over the age of 65, with many estimating over 20% of the senior population having the chronic disease. Since Type 2 diabetes is a significant cause of premature morbidity and mortality, prevention is important (Colberg, 2010). Regular physical activity can prevent or delay type 2 diabetes as well as affect lipid, the risk of cardiovascular events, blood pressure, and quality of life for the better (Colberg, 2010). A single session of aerobic exercise can improve insulin action and glucose tolerance for 24-72 hours, and the risk for someone with type 2 diabetes experiencing hypoglycemia due to prolonged physical activity is minimal. (Colberg, 2010). Resistance training resulted in a decrease in blood-glucose levels for 24 hours after exercise and greater reductions reported in higher volume or intensity exercises (Colberg, 2010).
Combining aerobic and resistance training may have the best effects on blood-glucose management. Increases in muscle mass from resistance training may improve blood-glucose uptake without altering insulin response, but aerobic exercises enhance insulin response (Colberg, 2010). The combination may be a key factor in lowering the effects for individuals suffering from diabetes. According to Colberg, et al. (2010), “even 1 week of aerobic training can improve whole-body insulin sensitivity in individuals with type 2 diabetes.”
Aerobic training can reduce total LDL cholesterol and raise HDL cholesterol, lowering the risk of high blood pressure (hypertension) and stroke (Colberg, 2010). Diabetes and hypertension share comorbidities with the risk of those who have both conditions seeing a 66-100% increase in vascular complications than either condition alone (Colberg, 2010). Higher levels of physical fitness reduce the risks of cardiovascular diseases and mortality. All-cause mortality and cardiovascular mortality risk is 1.7 to 6.6 times higher in those with low fitness levels and diabetes (Colberg, 2010). Regular exercise can prevent or delay the onset of type 2 diabetes. Even moderate-intensity exercise can reduce the risk of development of type 2 diabetes, with the Da Quing study in China showing 20 minutes of mild exercise can reduce the risk of diabetes by 46% (Colberg, 2010).
Exercise can Give You a Long and Healthy Life
A systemic review on literature in relation to life expectancy and physical activity showed that physical activity is indeed associated with an increase in life expectancy. Review of 13 studies showed results of eight cohorts seeing an increase of life expectancy by anywhere from 0.4 to 6.9 years due to physical activity (Reimers, 2012). Eleven studies that included confounding risk factors for mortality showed an increase in life expectancy from 0.4 to 4.2 years for those that exercised regularly (Reimers, 2012). When you exclude confounding factors like smoking or being obese, the life expectancy for fit men for instance jumps up to an average increase of 8.6 to 14.6 years with a confidence interval of 95% when compared with smoking, overweight, and physically unfit control subjects (Reimers, 2012). This increase of life expectancy did not seem to be associated with more years of frailty or dependence on assistance, rather it seemed that there were higher reports of gained disability-free years of life and greater life expectancy (Reimers, 2012).
A study published in the Journal of the Royal Society of Medicine in 1996 took a longitudinal review of runners versus non-runners in terms of the compression of morbidity. It found that individuals who exercised regularly saw a compression of morbidity. This included not only a longer lifespan but also the decline of health occurred over a shorter period (Fries, 1996, p. 67). The runner group exercised vigorously on average of 280 minutes per week (Fries, 1996, p. 66), which is nearly double the CDC’s minimum recommended exercise time of 150 minutes per week. Over the course of this nine-year study the researchers found persistent and striking differences between the runner vs non-running (control) group. The researchers predicted that the runner group had an expected two-year increase in longevity over the non-runner group. To highlight the difference, over the course of an eight-year mortality study the runner group’s mortality was 1.5% and the control group was 7% (Fries, 1996, pp. 66-67). They also found a 20% reduction of reported musculoskeletal pain for the exercise group compared to the control group (Fries, 1996, p. 67).
Another study of 18,670 individuals who started exercise in mid-life and continued higher fitness levels saw a lower risk of chronic conditions and suggested morbidity compression as well (Willis BL, 2012). The study focused on a “panel of 8 [chronic conditions] was used for the present analysis: congestive heart failure, ischemic heart disease, stroke, diabetes mellitus, chronic obstructive pulmonary disease, chronic kidney disease, Alzheimer disease, and colon or lung cancer.” After the combination of 120,780 person-person years of Medicare follow up, highest levels of fitness measurements saw lower incidence of developing any of the 8 chronic conditions measured in this study.
At the end of the study those with higher levels of mid-life fitness saw a greater morbidity compression ratio seeing a delay in the development of chronic conditions and extension of lifespan. Those with higher mid-life fitness also appeared to spend a greater proportion of their final five years of life with a lower incidence and burden of chronic conditions when compared to those with lower midlife fitness (Willis BL, 2012). According to Willis, et al. (2012), a mean fitness program of 150 minutes per week of moderate intensity exercise saw a reduction in chronic conditions by 20% in those over the age of 65. Lifestyle patterns such as regular exercise and dieting can delay the onset of morbidity thus compressing the timeline, allowing for longer lives with fewer years lived with chronic diseases.
References
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