Thursday, May 5, 2011
Aging, Part I
Back in the day when I still enjoyed alcohol and other things that altered my inefficient consciousness, I honestly liked getting sick. A three- or four-day flu was my specialty—the sore throat, achy chest and runny nose enabled me to legitimately take stuff like Robitussin and Nyquil, along with a variety of antihistamines, and almost knock myself out. The alcohol in cough syrups is designed to speed the medicine through the system, and it does this wondrously well. I could not be accused of being under the influence, I was ill, and anyone criticizing my way of dealing with my wretchedness was simply heartless and mean.
Things have changed. I now take great pains to avoid alcohol in any form, including medicine, and I have developed an intense fear and dislike of pills of all kinds. I no longer trust the prescriptions I am told to take and look them up on the Internet before I do. Are they addictive? Are they opiates or derivatives? What are the side-effects? I am, at best, a recalcitrant patient. Unfortunately, I also seem to get sick a lot more often now than I did two or three decades ago.
The aging process, we know, depends on a combination of both genetic and environmental factors, and it will occur at different rates in different people. Overall, genetic factors seem to be more powerful than environmental factors. Aging causes functional changes in cells; the rate at which cells multiply tends to slow down, and T-cell lymphocytes, important for our immune system to work properly, decrease with age. In addition, age causes changes in our responses to environmental stresses or exposures, such as ultraviolet light, heat, not enough oxygen, poor nutrition, and toxins.
Age also interferes with apoptosis, which programs cells to self-destruct or die at appropriate times. This process is necessary for tissues to remain healthy, and it is particularly important in slowing down immune responses once an infection has been cleared from the body. Cancer, for example, results in a loss of apoptosis. The cancer cells continue to multiply and invade or take over surrounding tissue, instead of dying as originally programmed. With Alzheimer’s, amyloid builds up and causes the early death of brain cells, which results in a progressive loss of memory and other brain functions.
And here’s unhappy news for all dieters: The proportion of the body that is made up of fat doubles between age 25 and age 75 and this change in body composition has an important effect on how the body handles various drugs. For example, when our body fat increases, drugs that are dissolved in fatty tissues remain in the body much longer than when our body was younger and more muscular. On a more positive note, body weight in men generally increases until their mid-fifties then decreases, with weight being lost faster in their late sixties and seventies. In women, body weight increases until the late sixties and then decreases at a rate slower than that of men.
We can also look forward to progressive changes in the heart and blood vessels that interfere with the body’s ability to control blood pressure. Nor does the body regulate its temperature as it could when younger. This can result in dangerously low body temperature from prolonged exposure to the cold or in heat stroke if the outside temperature is too high. There will be aging-related changes in the body’s ability to develop a fever in response to an infection. Another issue: The regulation of the amount and makeup of body fluids is slowed down in healthy older persons and problems in fluid regulation commonly develop during illness or other stress.
All this explains why getting older is not a particularly fun process. Want to see what you’ll look like when you’re old? Go to http://morph.cs.st-andrews.ac.uk/Transformer/