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Physical activity and lifespan
You may have heard the advice "If you exercise, you'll live longer." The good news -- or the bad news, if you hate doing anything more active than downloading iTunes -- is that it's true.Research backs this up. A 2007 study in the Journal of the American Medical Assn. found that fitter people lived longer, even if they had extra pounds around the middle. Among 2,603 adults 60 and older enrolled in that longitudinal study, the fittest people (those who did best on a treadmill test) also had the lowest risk factors for hypertension, diabetes and high cholesterol.
Most of the negative changes to our bodies over time can be chalked up to two things, says Wojtek Chodzko-Zajko, head of the department of kinesiology at the University of Illinois at Urbana-Champaign: normal aging and disease-related aging (that is, changes accelerated by illnesses and conditions such as diabetes and heart disease).
Exercise, he says, can reduce the severity of both types.
Strength maintenance: Normal aging results in a gradual loss of muscle mass (about 1% a year) that begins in middle age.
Strength-training can offset this loss, called sarcopenia, Chodzko-Zajko says. "The link between functionality and longevity may be indirect but more muscle mass allows you to be ambulatory and maintain function, whereas in a wheelchair you can't."
Having stronger muscles -- especially leg muscles -- and better balance may mean fewer falls, a leading cause of death among the elderly, according to the American Geriatrics Society. Cardiovascular health: Over time, arteries become stiffer, paving the way for cardiovascular disease. The chemical composition of the artery walls begins to shift, says Douglas Seals, a professor in the department of integrative physiology at the University of Colorado, making the walls more rigid.
"That stiffening of the arteries can cause changes in your blood pressure," putting extra stress on the heart, Seals adds.
Regular aerobic exercise, he says, slows or reverses some of the changes.
Diabetes risk: As we age, blood-glucose control becomes less robust, making us more insulin-resistant and increasingly susceptible to diabetes. People also tend to gain weight as they age, further upping the chances for developing the disease.
During aerobic exercise, muscles take up glucose from the blood and use it for fuel, keeping the body's blood sugar levels low. Exercise also causes the pancreas to decrease production of insulin. Continuous, steady exercise especially causes the liver to take lactic acid, amino acids and fats and turn them into glucose, further feeding the muscles and regulating blood sugar levels.
Inflammation control: Inflammation can also worsen as we age and become exacerbated by extra weight, upping the risk for cardiovascular disease, lowering the immune system and paving the way for bacteria and viruses to take hold -- even cancer cells to grow. But exercise may cause a decrease in levels of C-reactive protein, a marker for inflammation.
Obes Rev. 2009 Sep 9.
Physical activity, fitness and fatness: relations to mortality, morbidity and disease risk factors. A systematic review.
Fogelholm M.
The Academy of Finland, Health Research Unit, Helsinki, Finland.
Summary: The purpose of this systematic review was to study the relative health risks of poor cardio-respiratory fitness (or physical inactivity) in normal-weight people vs. obesity in individuals with good cardio-respiratory fitness (or high physical activity). The core inclusion criteria were: publication year 1990 or later; adult participants; design prospective follow-up, case-control or cross-sectional; data on cardio-respiratory fitness and/or physical activity; data on BMI (body mass index), waist circumference or body composition; outcome data on all-cause mortality, cardiovascular disease mortality, cardiovascular disease incidence, type 2 diabetes or cardiovascular and type 2 diabetes risk factors. Thirty-six publications filled the criteria for inclusion. The data indicate that
the risk for all-cause and cardiovascular mortality was lower in individuals with high BMI and good aerobic fitness, compared with individuals with normal BMI and poor fitness.
In contrast,
having high BMI even with high physical activity was a greater risk for the incidence of type 2 diabetes and the prevalence of cardiovascular and diabetes risk factors, compared with normal BMI with low physical activity.
The conclusions of the present review may not be applicable to individuals with BMI > 35.
physical, exercises, cooper, bmi, fitness, mortality, aerobic, cardio, sarcopenia.
