I thought I’d share an excerpt from it with you today. Here is what John J. Ratey, author of Spark: The Revolutionary New Science of Exercise and the Brain has to say (except for bullet points, the emphases are mine):
Here’s how exercise keeps you going:
- It strengthens the cardiovascular system. A strong heart and lungs reduce resting blood pressure. The result is less strain on the vessels in the body and the brain. There are a number of mechanisms at work here. First, contracting muscles during exercise releases growth factors such as VEGF and fibroblast growth factor (FGF-2). Aside from their role in helping neurons bind and promoting neurogenesis, they trigger a molecular chain reaction that produces endothelial cells, which make up the inner lining of blood vessels and thus are important for building new ones. These inroads expand the vascular network, bringing each area of the brain that much closer to a lifeline and creating redundant ciruclation routes that protect against future blockages. Second, exercise introduces more nitric oxide, a gas that widens the vessels’ passageways to boost blood volume. Third, the increased blood flow during moderate to intense activity reduces hardening of the brain arteries. Finally, exercise can to some extent counteract vascular damage. Stroke victims and even Alzheimer’s patients who participate in aerobic exercise improve their scores on cognitive tests. Starting when you’re young is best, but it’s never too late.
- It regulates fuel. Researchers at the Karolinska Institute conducted a nine-year study of 1,173 people over age seventy-five. None of them had diabetes, but those with high glucose levels were 77 percent more likely to develop Alzheimer’s. As we age, insulin levels drop and glucose can skyrocket, which creastes waste products in the cells – such as free radicals – and damages blood vessels, putting us at risk for stroke and Alzheimer’s. When everything is balanced, insulin works against the buildup of amyloid plaque, but too much encourages the buildup, as well as inflammation, damaging surrounding neurons. Exercise increases levels of insulin-like growth factor (IGF-1), which regulates insulin in the body and improves synaptic plasticity in the brain. By drawing down surplus fuel, exercise also bolsters our supply of BDNF, which is reduced by high glucose.
- It reduces obesity. Aside from wreaking havoc on the cardiovascular and metabolic systems, body fat has its own nasty effects on the brain. The CDC estimates that 73 percent of Americans over sixty-five are overweight, and, given the potential problems obesity can lead to – from cardiovascular disease to diabetes – the agency is right in declaring it a pandemic. Simply being overweight doubles the chances of developing dementia, and if we factor in high blood pressure and high cholesterol – symptoms that often come along with obesity – the risk increases sixfold. When people retire they figure they deserve a break after working their whole lives, and they start piling on the food. But what they don’t realize is that having dessert with every meal is no treat. Exercise, naturally, counteracts obesity on two fronts: it burns calories, and it reduces appetite.
- It elevates your stress threshold. Exercise combats the corrosive effects of too much cortisol, a product of chronic stress that can bring on depression and dementia. It also bolsters neurons against excess glucose, free radicals, and the excitatory neurotransmitter glutamate, all necessary, but they can damage cells if left unchecked. Waste accumulates and junks up the cellular machinery, and it starts turning out dangerous products – damaged proteins and broken fragments of DNA that trigger the latent and ultimately inevitable process of cell death that defines aging. Exercise makes proteins that fix the damage and delay the process.
- It lifts your mood. More neurotransmitters, neurotrophins, and connectivity shore up the hippocampus against the atrophy associated with depression and anxiety. And a number of studies have shown that keeping our mood up reduces our chances of developing dementia. The evidence applies not only to clinical depression but also to general attitude. Staying mobile also allows us to stay involved, keep up with people, and make new friends; social connections are important in elevating and sustaining mood.
- It boosts the immune system. Stress and age depress the immune response, and exercise strengthens it directly in two important ways. First, even moderate activity levels rally the immune system’s antibodies and lymphocytes, which you probably know as T cells. Antibodies attack bacterial and viral infections, and having more T cells makes the body more alert to the development of conditions such as cancer. Population studies bear this out: The most consistent risk factor for cancer is lack of activity. Those who are physically active, for instance, have a 50 percent lower chance of developing colon cancer. Second, part of the immune system’s job is to activate cells that fix damaged tissue. When it’s out of whack, these damaged spots fester, and you’re left with chronic inflammation. This is why, if you’re over fifty, your blood will be tested for C-reactive proteins as part of your standard physical. These proteins are a sign of chronic inflammation, a primary risk factor for cardiovascular disease and Alzheimer’s. Exercise brings the immune system back into equilibrium so it can stop inflammation and combat disease.
- It fortifies your bones. Osteoporosis doesn’t have much to do with the brain, but it’s important to mention because you need a strong carriage to continue exercising as you age, and it is a largely preventable disease. Osteoporosis afflicts twenty million women and two million men in this country. More women every year die from hip fractures – a vulnerability of osteoporosis – than from breast cancer. Women reach peak bone mass at around thirty, and after that they lose about 1 percent a year until menopause, when the pace doubles. The result is that by age sixty, about 30 percent of a woman’s bone mass has disappeared. Unless, that is, she takes calcium and vitamin D (which comes free with ten minutes of morning sun a day) and does some form of exercise or strength training to stress the bones. Walking doesn’t quite do the job – save that for later in life. But as a young adult, weight training or any sport that involves running or jumping will counteract the natural loss. The degree to which you can prevent the loss is impressive: one study found that women can double their leg strength in just a few months of weight training. Even women in their nineties can improve their strength and prevent this heartbreaking disease.
- It boosts motivation. The road to successful aging really begins with desire, because without the desire to stay engaged and active and alive, people quickly fall into the death trap of being sedentary and solitary. One of the problems of getting older is the lack of challenges, but with exercise we can continually improve and push ourselves. Exercise counteracts the natural decline of dopamine, the key neurotransmitter in the motivation and motor systems. When you move, you’re inherently boosting motivation by strengthening the connections between dopamine neurons, while at the same time guarding against Parkinson’s. This really underscores the idea that if you’re not busy living, your body will be busy dying. It’s important to have plans and goals and appointments, and this is why sports such as golf and tennis are great. They require constant self-monitoring and the motivation to improve.
- It fosters neuroplasticity. The best way to guard against neurodegenerative diseases is to build a strong brain. Aerobic exercise accomplishes this by strengthening connections between your brain cells, creating more synapses to expand the web of connections, and spurring newly born stem cells to divide and become functional neurons in the hippocampus. Moving the body keeps the brain growing by elevating the supply of neurotrophic factors necessary for neuroplasticity and neurogenesis, which would otherwise naturally diminish with age. Contracting your muscles releases factors such a VEGF, FGF-2, and IGF-1 that make their way from the body into the brain and aid in the process. All these structural changes improve your brain’s ability to learn and remember, execute higher thought processes, and manage your emotions. The more robust the connections, the better prepared your brain will be to handle any damage it might experience.