How does exercise prolong life? The leading theory is that exercise prolongs life and prevents heart attacks and cancers by causing the body to dispose of free radicals with increased production of antioxidants.
Exercise speeds up the reactions that turn food into energy, so exercise actually increases the production of free radicals. The body responds to this increased production of free radicals during exercise by producing tremendous amounts of antioxidants that sop up the free radicals and render them harmless.
Most cells in your body have mitochondria, very small energy-producing chambers that number anywhere from a few to thousands in each cell. As you age, mitochondria in muscles decrease in number and size. This interferes with your body's ability to burn sugar efficiently for energy, so they produce more free radicals. Anything that increases the number and size of mitochondria helps to protect you from free radicals. Exercising helps to prevent loss of mitochondria and even makes them larger (Exercise and Sport Sciences Reviews, April, 2007).
• Mitochondria convert molecules from the sugar in food that you eat to other molecules to release energy to power most cells in your body.
• They do this by shuffling electrons from one molecule to another.
• As electrons are shuffled to produce energy, extra electrons accumulate inside mitochondria.
• Free electrons must attach immediately to something.
• They can attach to hydrogen atoms to form water and become harmless, or
• They can attach to oxygen atoms to form free radicals that can damage cells.
• Free radicals attach to your DNA genetic material in cells to damage them which causes cells to act differently than they are supposed to.
• The genetic material in cells tells the cell what to do.
• If your genetic material is functioning properly, it directs the cell to divide a certain number of times and then die, called apoptosis.
• If you genetic material in cells is damaged, the cells can become defective and go on to live forever to become cancers. • Cells with damaged genetic material also can cause heart attacks and other life-shortening conditions.
Furthermore, a team from Yale University showed that as you age, you lose your ability to make the enzyme AMP-activated protein kinase (AMPK). This enzyme functions to increase mitochondria in muscles (Cell Metabolism, February 2007). Anything that reduces the number or efficiency of mitochondria interferes with your body's ability to burn sugar for energy. As a result, blood sugar, fat and cholesterol levels rise. The extra calories that are not burned accumulate in your body as fat in your muscles, liver and fat cells. This causes you to gain weight. Extra fat in cells block their ability to take in sugar from the blood stream, so blood sugar levels rise and you are at increased risk for developing diabetes. Extra fat in the liver prevent the liver from removing extra insulin, so insulin levels rise to constrict arteries and cause heart attacks. Insulin also makes you hungry all the time to increase your chances of gaining weight.
AMPK is increased by exercise and by some of the drugs used to treat diabetes, such as metformin. The best way to increase the number and size of mitochondria in your cells is to exercise. If you do not have a regular exercise program, you are shortening your life.