Prime Time - Jane Fonda [36]
The cardiorespiratory system is responsible for delivering blood, which carries oxygen and nutrients, to every cell in the body, and for carrying away carbon dioxide and other waste products. This is the system that supplies the muscles with the oxygen essential for burning calories for energy. It determines our “maximum aerobic capacity,” or V02 max, as it’s known in sports circles. This is one of the most critical measures of our body’s performance: how much oxygen we take in; how much blood is pumped, and with what degree of ease, throughout the body; and how well oxygen is taken up and utilized by the muscles and other cells. These dynamics are a master key to our vitality.
With age, the heart and the circulatory system gradually begin to lose some of their effectiveness. After age thirty, there is an average decline of about 1 percent a year in our V02, or aerobic, capacity. The lungs are less elastic and, because they can accept less air, transfer less oxygen into the blood. The heart muscle and the blood vessels thicken and become more rigid, which means that each stroke of the heart pumps less blood. Inelastic and narrowed arteries cause the heart to work harder to move blood from the chest to the head, arms, and legs. As the heart pushes the blood more forcibly through the circulatory network, our blood pressure tends to rise.
All of this is common and needn’t mean a loss of basic health, provided we don’t also become sedentary. Inactivity increases the likelihood that fatty plaque will begin to cling to our arterial walls, causing atherosclerosis and chronic hypertension, which can spiral into a heart attack or, if the brain is involved, a stroke. Atherosclerosis, hypertension, heart attack, and stroke combined account for half of all disabling health problems in women and men alike.
So just do it! Stay vigorously and aerobically active!
I was 72 and was doing my first workout DVD for boomers and seniors after twenty years out of the business.
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Aerobics and Your Brain
“Perhaps the most direct route to a fit mind is through a fit body,”3 says Jane Brody, the wonderful health writer for the New York Times. All brain experts will tell you that physical activity will do more for your brain health than the expensive computer-based brain games that are so much the rage these days. (Although Dr. Michael Hewitt, at Canyon Ranch, suggests that doing both might be the smartest move of all!)
Obviously, aerobic fitness helps the brain by reducing the risk of heart attack and stroke. But it also improves cognitive functioning by slowing the age-related shrinkage of the frontal cortex of the brain, which is where “executive functions” like reasoning and problem solving take place.
In a 2007 New York Times op-ed piece, Dr. Sandra Aamodt, a freelance science writer and former editor in chief of Nature Neuroscience, and Dr. Sam Wang, an associate professor of neuroscience at Princeton University, wrote, “Exercise causes the release of growth factors, proteins that increase the number of connections between neurons, and the birth of neurons in the hippocampus,” which is the seat of memory and where Alzheimer’s disease starts. Reports show that as many as fifty million older Americans may get Alzheimer’s by midcentury. While research is under way to prevent or postpone the disease, scientists already know, as Jane Brody writes, that “people who exercise regularly in midlife are one-third as likely to develop Alzheimer’s in their 70s. Even those who start exercising in their 60s cut their risk of dementia in half.”4
A decline in cognitive functioning has long been seen as a “typical” part of aging, but it is not normal. New brain science now