Tuesday, November 15, 2016

The Aging Process. - 2

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.

Age and Body Temperature:
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. ]

Gastronomical Effects of Aging
  
You may not think of your mouth as being part of the gastrointestinal system, but in fact, it's the very starting point of the process by which you digest foods and absorb nutrients. As you age, chewing can become more difficult, you may chew more slowly, and you may not chew your food as efficiently. That's especially true if you have dentures or poor dentition.
Chewing is important, though, because it breaks down food so that stomach acid and intestinal enzymes can better attack it, digesting it to its smallest components to be absorbed by the intestine. When you swallow larger pieces of food, it takes about 50 to 100 percent longer for it to make its way to your stomach because your esophagus, the pipe that connects your mouth with your stomach, doesn't contract as forcefully as it did when you were younger.

As a result, you are also more vulnerable to choking. Slowing down and chewing food thoroughly will help you make the most out of your eating experience and help eliminate some of the problems caused by gulping larger chunks of food. As many as 30 percent of Americans over the age of 60 do not produce enough stomach acid because of two conditions: hypotrophic gastritis (reduced production of stomach acid) or atrophic gastritis (the absence of stomach acid).
You may not feel either of these conditions, but their effects are real. Too little stomach acid results in faulty vitamin B12 absorption. A deficiency of vitamin B12 in your bloodstream and tissues can lead to pernicious anemia and irreversible nervous-system impairment and may contribute to high levels of homocysteine in your blood. High homocysteine is one of the risk factors for heart disease.
People over age 60 have a greater risk of developing gallstones, perhaps because of the narrowing of the bile duct at the opening of the intestine. A high fat diet also puts you at greater risk. When you digest fat you need bile, a substance made by the liver and stored in the gallbladder. Gallstones form when liquid stored in the gallbladder hardens into rock-hard material.
As you get older, you produce less lactase, the digestive enzyme that breaks down the carbohydrate in dairy products known as lactose. It's difficult to pinpoint how many older people can't tolerate the likes of milk, cheese, and ice cream. But if you have bloating and discomfort beginning within hours of eating dairy products, you probably have some diminished tolerance for lactose.
Lactose intolerance is individual. That's why you may be able to tolerate some dairy products and not others. For example, many people with lactose intolerance can eat yogurt, which is lower in lactose than a glass of milk. In addition, consuming milk or other dairy products with food helps to decrease the effects of lactose intolerance, as does consuming smaller amounts at a time.
As you get older, your gut -- particularly your colon -- may become sluggish and less toned. One in three people age 60 or older have diverticula, which are outpouchings in the lining of the large intestine. These pouches are the result of increased pressure within the intestine caused by decreased muscle tone. In addition, when your gut gets sluggish, you become more vulnerable to constipation.
Your liver is your largest internal organ, weighing in at about three pounds. But it gets smaller with time, beginning around age 50. The liver's shrinkage begins at the same time that body weight and muscle mass start their decline. However, in the very old, the liver becomes disproportionately small. Having less liver tissue and decreased blood flow to this organ means that your body may handle certain medications differently.
That's why the older you get, the more often you and your doctor should evaluate the effect of all of the medications you take and discuss your alcohol intake.
You can't live without it, but you probably know little about why your liver is so important. The liver:
  • makes bile, which helps you digest fat
  • helps determine the amount of nutrients that are sent to the rest of your body
  • stores glycogen, a complex carbohydrate that is converted to sugar and released into the bloodstream, providing fuel for your body when your blood sugar level falls
  • synthesizes many proteins
  • processes drugs that have been absorbed by the digestive tract into easy-to-use forms for the body
  • detoxifies and gets rid of substances that would otherwise be poisonous, such as the waste products from the breakdown of medications and alcoh
With time, you may become infected with Helicobacter pylori (H. pylori) -- a pesky bacteria that hitches a ride on the stomach lining and is the cause of nearly all ulcers. Ulcers are sores or holes in the lining of the stomach or duodenum, a part of the small intestine. They cause pain when the stomach is empty, such as between meals and in the wee hours of the morning, but irritation can come at any time.
Sometimes the pain lasts for minutes; other times it hangs around for hours. Eating or taking antacids may relieve your distress, but only temporarily. H. Pylori infects about 60 percent of American adults by age 60, but infection with the bacterium does not necessarily mean you will develop an ulcer.
However, the presence of H. Pylori does increase your chances because it weakens the protective mucous coating in the digestive tract and makes it vulnerable to the corrosive effects of stomach acid. H. pylori infection is easily cured with antibiotics, sometimes in combination with acid-suppressing medication to alleviate the symptoms and heal the ulcer.
How will you know if H. pylori is plaguing you? Your health care provider can use any of the following tests to diagnose H. pylori infection:
  • Blood tests: A blood test can confirm H. pylori infection.
  • Breath tests: This involves drinking a harmless liquid and having a sample of your breath tested one hour later to detect H. pylori.
  • Endoscopy: A small tube with a camera inside is inserted through your mouth and into the stomach to look for ulcers. During this procedure, small samples of the stomach lining can be gathered for testing for H. pylori.
You've got two of them, and boy, are they a busy pair. All the blood in your body is constantly filtered by the kidneys, which determine the elements to keep and those to eliminate in urine. Without adequate kidney function, you would not be able to clear toxic byproducts of normal metabolism or those of medication breakdown.
Nor would you be able to regulate water balance and blood pressure. Functioning kidneys actually participate in bone health, too, by finishing off vitamin D production that begins in the skin and by regulating calcium and phosphorus loss in urine.
When you're born, each kidney tips the scale at a shade more than 1.5 ounces. As you grow, so do they -- to about nine ounces a piece. But as you age, they begin to decrease in size. By your eighties, they've shrunk to about six ounces each. Kidneys also gradually become less efficient at filtering your blood and making urine, beginning around age 30. And as you get on, less blood makes it to the kidneys.
While scientists agree that kidney function drops off with age, they can't agree on why. It could be that you lose nephrons, or kidney cells, and this decreases the organs' capabilities. Some say that undetected infection, injury, and medication reactions and a decrease in blood flow caused by vascular disease may be the reason that kidney function flounders.
Whatever the cause, you can preserve kidney function by drinking plenty of fluids; controlling cardiovascular disease, including high blood pressure, as much as possible; and keeping blood glucose levels in check, especially if you have been diagnosed with diabetes. Chronically high blood glucose destroys the tiny blood vessels that supply the kidneys, causing cell damage and death.
Now that you've digested a hearty amount of information about the gastronomical effects of aging, it's time to learn about the immunological effects of aging. Continue to the next post to find out more.


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