Today I'll point out a few recent studies on exercise and age-related disease in human populations. Animal studies show that regular exercise improves health and extends healthspan, the period of life free from age-related conditions. Human studies, which use statistical methods on large sets of population data, tend to show correlations only, but these correlations match what is seen in animal studies. It is not unreasonable to believe based on the evidence that exercise is good for you over the long term, and that maintaining fitness as you age reduces the risk of suffering all of the common age-related diseases - that this is causation, not just correlation. In an age of rapid progress in biotechnology, postponing aspects of the inevitable decline of old age, even for just few years, increases the odds of being around and in good shape to benefit from the rejuvenation therapies that are envisaged, in development, but yet to be realized.
In the long run, yes, only progress in medical science can save us from aging to death. As we grow older and ever more damaged, the span of life remaining is increasingly determined by the capabilities of the medical community and how rapidly those capabilities are improving. So in a sense we'll all need to be rescued by that progress - you can't exercise your way to agelessness. But why sabotage yourself and reduce your odds living to benefit from greatly improved medicine when that much of your fate at least is absolutely under your control? Being sedentary and unfit has a cost, both additional lifetime medical expenditure and lost years of life expectancy. You can always choose not to pay that cost, to be healthier.
"While everyone's lung function declines with age, the actual trajectory of this decline varies among individuals. What is less known is, beyond smoking, what factors affect this rate of decline. Even though the majority of people will not develop lung disease in their lifetime, declining lung function is known to increase overall morbidity and mortality even in the absence of overt pulmonary disease." Researchers analyzed data from the CARDIA (Coronary Risk Development in Young Adults) Study, which began in 1985-86 with 5,115 healthy black and white men and women, aged 18-30. The study has measured participant's cardiopulmonary fitness periodically over 20 years using a graded treadmill test. At the beginning of the study and at each follow-up assessment, pulmonary function (PF) was also assessed by measuring forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). After adjusting for age, smoking, body mass index and change in BMI, the association between fitness and lung function remained statistically significant.
Researchers found that participants in the top quartile of baseline fitness experienced the least annual decline in PF. Participants with the greatest decline in fitness experienced the greatest decline in FEV1 and PF over 20 years. Participants with sustained or improved fitness experienced the least decline in PF over 20 years.
Recent research suggests that exercise might provide some measure of protection from Alzheimer's disease and other dementias. Thirty men and women ages 59-69 were put through treadmill fitness assessments and ultrasounds of the heart. Then they received brain scans to look for blood flow to certain areas of the brain. "We set out to characterize the relationship between heart function, fitness, and cerebral blood flow, which no other study had explored to date. In other words, if you're in good physical shape, does that improve blood flow to critical areas of the brain? And does that improved blood flow provide some form of protection from dementia?"
The results showed blood flow to critical areas of the brain - and so the supply of oxygen and vital nutrients - was higher in those who were more physically fit. "Can we prove irrefutably that increased fitness will prevent Alzheimer's disease? Not at this point. But this is an important first step towards demonstrating that being physically active improves blood flow to the brain and confers some protection from dementia, and conversely that people who live sedentary lifestyles, especially those who are genetically predisposed to Alzheimer's, might be more susceptible." Since people who exercise frequently often have reduced arterial stiffness, researchers postulate that regular physical activity - regardless of age - maintains the integrity of the "pipes" that carry blood to the brain. "In the mid-late 20th century, much of the research into dementias like Alzheimer's focused on vascular contributions to disease, but the discovery of amyloid plaques and tangles took prevailing research in a different direction. Research like this heralds a return to the exploration of the ways the vascular system contributes to the disease process."
Higher levels of leisure-time physical activity were associated with lower risks for 13 types of cancers, according to a new study. Physical inactivity is common, with an estimated 51 percent of people in the United States and 31 percent of people worldwide not meeting recommended physical activity levels. Researchers pooled data from 12 U.S. and European cohorts (groups of study participants) with self-reported physical activity (1987-2004). They analyzed associations of physical activity with the incidence of 26 kinds of cancer. The study included 1.4 million participants and 186,932 cancers were identified during a median of 11 years of follow-up. The authors report that higher levels of physical activity compared to lower levels were associated with lower risks of 13 of 26 cancers. Most of the associations remained regardless of body size or smoking history, according to the article. Overall, a higher level of physical activity was associated with a 7 percent lower risk of total cancer.