Not too hot, not too cold? As we age, we lose some of our ability to regulate body temperature. A room that has a twenty-year-old running for a heavy sweater or sweating buckets may feel perfectly comfortable to a grandparent. Physical changes discussed earlier, such as loss of muscle, as well as reduced energy production, are partially responsible for decreased perception of cold.
In addition, blood vessels in the skin do not have the same youthful ability to constrict in order to conserve heat, and you may not be able to shiver, which is heat-producing.
Older people also lack the ability to dissipate normal body heat, and because of a decreased sense of thirst, they are more likely to be suffering from a lack of fluid. Thyroid disease, which is increasingly prevalent in older adults, can also be responsible for thermal insensitivity.
All these changes make older people more susceptible to both hypothermia, a condition in which body temperature dips below 96 degrees Fahrenheit, and heatstroke. Both conditions are life-threatening.
People age 75 and older are five times more likely to die of hypothermia than young people. Symptoms of hypothermia include sleepiness or confusion; leg or arm stiffness; slow, slurred speech; and low pulse rate.
Cardiovascular Effects of Aging
Aging brings on increased stiffness of the chest wall, diminished blood flow through the lungs, and a reduction in the strength of your heartbeat. (In fact, maximum heart rate per minute declines with each year and can be estimated by subtracting your age from 220.) Don't worry too much about this, though. Your heart pumps more blood per beat to compensate for a diminishing heart rate.
Older people take longer to recover from stress, a shock, or surprise. After exertion, such as exercise, more time passes before your body returns to its resting heart rate and blood pressure. Older people often feel colder than their younger counterparts, largely due to diminished circulation. Blood vessels change, too. Artery walls slowly thicken and become less elastic, increasing their vulnerability to normal wear and tear.
While arterial thickening is considered normal, it may predispose you to the buildup of plaque inside your arteries. Plaque restricts the flow of blood to the heart and the brain, which can lead to heart attack or stroke.
Plaque buildup increases with age but is exacerbated by elevated total cholesterol levels and by elevated LDL (low density lipoproteins, the "bad" cholesterol) levels in the blood. A diet rich in saturated fat and cholesterol and low in fiber coupled with a sedentary lifestyle contribute to high blood levels of total cholesterol and LDL cholesterol.
Until about age 50, men have higher blood cholesterol concentrations than women. That's thought to be the result of the protective function of estrogen, a female hormone that helps keep blood cholesterol levels in check. Even when estrogen levels fall and blood cholesterol levels rise after menopause, women still run a lower risk of heart attack and stroke from clogged arteries than their male peers.
Because they haven't been suffering from the same damaging high cholesterol levels as men, women suffer from heart attack and stroke an average of ten years later in life than men. But once menopause starts, a woman's risk for heart attack and stroke rises steadily with each passing year. Between 40 and 50 percent of people over the age of 65 have high blood pressure, yet scientists are not sure why.
In about 95 percent of the cases the cause remains a mystery. The decreased elasticity of the blood vessels as we age may be at least partially responsible for high blood pressure, but lifestyle may be equally, if not more, responsible. Studies show that less technologically advanced countries have virtually no high blood pressure with advancing age, while industrialized nations such as the United States show a steady increase.
Why does it matter? Elevated blood pressure harms blood vessels. You may feel fine, but out-of-control blood pressure is an insidious condition that puts you at greater risk for stroke, heart disease, kidney failure, and other ailments.
Continue to the next page to read about the gastronomical effects of aging.
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