I'm just going to post the many benefits of physical exercise and prove why disuse is one of the factors of aging rather than disease and time. Aging can help slow down some of the physiological processes that are associated with aging. I'm just going to list what I read in my book, "The Physical Dimensions of Aging." I should really be writing papers right now, lol, but I felt the need to post this and point out some important things and misconceptions about aging and exercise.
-4 of the top 5 causes of death in adults are attributable to deterioration of the cardiovascular and respiratory system. Aging and disuse degrade these systems, whereas systematic exercise generally enhances them. (I'm sure you've heard this before!)
-The primary structural changes of the aging cardiovascular system include an increased thickening of the walls of the blood vessels and left ventricle, an increased stiffness in the aorta and arterial tree, and an increase in size of the left atrial chamber of the heart (exercise and prevent/slow this from happening...but it has to be habitual exercise throughout life.)
-Now, thickening of the vessel walls is a strong predictor of stroke and cardiovascular disease. (Ahhhh! When blood vessels are thicker, blood cannot flow as freely, eventually clotting somewhere in there, leading to decreased oxygen to the brain, which=a stroke! or decreased blood flow to the heart, which=some heart disease)
-By age 75, 54% of men and 66% of women report no physical activity :(
-Now, the recruitment of skeletal muscle during exercise results in an increase in oxygen consumption (VO2)
-The more intense the level of exercise, the greater the oxygen requirement. VO2 increases as a linear function with increasing exercise intensity and will reach a max value at exhaustion.
-Longer endurance training programs of moderate to high intensity elicited increases in VO2max in older adults SIMILAR IN RELATIVE MAGNITUDE TO THOSE SEEN IN YOUNG ADULTS (keep fit your whole life so you can better use oxygen as you age and will not be dependent on others when you get really old!)
-This was really interesting to me-The highest levels of VO2max, at any age, are those exhibited by competitive runners who maintain an intense, daily training schedule and who compete regularly-(this shows it's important to be physically active your whole life! And my guess is why runners, not swimmers or cyclists, have the highest VO2max values is because running is the most basic form of human movement. You can push yourself to your max very easily. With swimming, it requires more skill and technique, one may not be pushing themselves to their max or even able to get up to their max values if they can't even swim right. With cycling, again, foreign object under you; you're only using your legs. Using your arms as well helps to get your heart rate up even more. I'm not going to develop these ideas more fully, don't have time. Anyways, of course there are some people who are swimmers and cyclists who can maintain very high levels of their VO2max throughout life :) Look at Lance! ha
-This was awesome-"Shepherd (1987) suggested that an increase in VO2max of 20% is not trivial. He maintained that a gain of this size "offers the equivalent of 20yrs of rejuvenation-a benefit that can be matched by no other treatment or lifestyle change"-again, goes to show habitual physical activity really is the best medicine....
-Frequency of exercise, rather than intensity, is more important for optimizing blood pressure. Daily exercise is the most beneficial activity. And this reason, is why I believe I must do something every single day. Obviously if I go real hard one day, I take the next day or two easy (in a different sport, perhaps!). But I still do something. I want to get the increased oxygen blood flow to my brain to help me think more clearly, and help my mood, as well as keeping my health #'s low. I may be OCD about this, but hey, I don't care, it's being healthy. Sometimes it is OK to take days off, though.
-Again, the American College of Sports Med states that the important exercise criterion is frequency rather than intensity, with daily exercise being most beneficial.
-Active people have lower blood triglycerides and more high-density lipoprotein cholesterol (helps off set a cholesterol imbalance, the more you have, the more you are protected against heart disease), and they generally report less anxiety and depression (oh God, if I didn't exercise, I can't imagine how moody I'd be. I still get moody even though I exercise regularly!)
-Coronary arteries of endurance-trained individuals can expand more, are less stiff in older age, and are wider than those of unfit subjects (meaning more oxygen-rich blood flow!)
-There is some evidence that exercise may decrease the potential for clot formation; thus, with larger, more compliant coronary arteries and a diminished likelihood of forming clots, the active individual of any age is at a lower risk for a heart attack. Additionally, the heart muscle itself becomes bigger and stronger with regular exercise. Cool.
-It is clear that daily physical activity is important for optimal physical and psychological function even for the extremely old and frail, although the goals of the exercise program as well as the exercises will be altered to accomodate individual disabilities.
-However, it cannot be assumed that the physical work capacity of all individuals, if they followed a similar lifestyle, would be similar to that of masters athletes, because about 40% of an individual's physiological athletic capability is attributed to genetic factors-interesting.
-Some researchers suggest that highly trained endurance athletes and moderately trained fitness participants who maintain high-intensity training may experience less decline in aerobic capacity than sedentary individuals (book and teacher pointed out that if you were once an athlete, this does NOT protect you. you must continue to train.)
-The major determinants of changes in VO2max with age were the initial level of aerobic power and the subject's reduction in activity level.---ahhhh stay active so you will be able to use oxygen very well throughout life; activities of daily living won't be a challenge for you when you're older.
-The encouraging aspect of these studies of highly trained aged competitiors (masters athletes) is that a decade of aging (50-60) may have little effect on a highly exercised cardiovascular system. The VO2max values of current masters athletes reveal strikingly youthful cardiovascular function--see, we can slow down the aging process with regular exercise!
-So....some measures of fitness decline by 50% within 3 weeks, and light or moderate exercisers who quit exercising may lose all exercise benefits within a few months.
-Again, my book states "To provide long-term benefits, exercise must become an integral, daily part of an individual's life."
Take a look at what disuse, bed rest, and deconditioning can do to your body:
-Experiments on bed rest have shown that even a short period of physical inactivity, even in relatively YOUNG SUBJECTS, can have NEGATIVE effects on the cardiovascular function, blood pressure, and hormonal responses to exercise. Twenty days of bed rest in young adults led to a 25%! decline in VO2max, whereas 4 months of detraining in older adults led to a complete loss of endurance training adaptations of the cardiovascular system.
-In the detraining study for 60yr olds, there was an increase in VO2max of 16%! after 16 weeks of supervised training on a cycle ergometer. However, all of this gain in aerobic power was lost when the subjects were discharged from the study.
-A lifetime of physical disuse can have catastrophic effects, eroding strength and mobility, and may eventually lead to frailty, immobility, and total dependency. ahhhhhhh!
-One last fun fact: Exercising the lower limbs assists in venous return (returning blood to the heart thru the veins), improving the blood flow and pressure needed to maintain adequate perfusion of the brain.
One story my book shares: Effects of Disuse: A Personal Testimony
Bortz (1983) articularted the deleterious effects that disuse has on the body from he personal experience with a leg broken during a skiing accident:
"When the cast was removed, I found my leg giving all the appearance of the limb of a person 40 or 50yrs older. It was withered, discolored, stiff, painful. I could not believe this leg belonged to me. This similarity of changes due to enforced inactivity to those commonly attributed with aging was striking. And, in fact, if one were to go to all the standard textbooks of geriatrics and write down all the changes which seem to accompany aging, set the list aside, and then go to the textbooks of work physiology and write down all the changes subsequent to inactivity--and then compare the 2 lists, one would see that they are virtually identical. The coincidence is not random. It is intense. It forces the conclusion that at least part of what passes as change due to age is not caused by at age at all, but by disuse." Scary. Stay active so you can enjoy and live life to it's fullest when you're 50, 60, 70, 80, 90...etc. :)
-also if interested, read this story about an 80yr old who was inactive her whole life, got a ton of diseases related to aging, but once started walking, was off meds in a yr or 2 and started competing and winning events in the Senior Olympics. Darn, I can't post the site here I guess, but look up Eula M. Findley Weaver.
Also I have been taught this and read an article this morning including a study by this guy Steven N. Blair who works at the Cooper Institute in Dallas, TX who studies heart disease...that you can be fit and fat, as long as you're #'s are low (heart rate, blood pressure, cholesterol, etc.) and you generally eat pretty well and exercise on a regular basis. Cool. :)
Also, I am doing my masters thesis on how exercise can help improve cognitive function/prevent short term memory loss. I already know that it helps increase blood flow to the brain, and I've been reading studies that this can help prevent/or maybe I should say prolong the risk of dementia and alzhiemer's in older adults, but only if they are moderate to high intensity regular exercisers. Interesting, because as you age oxygen to the brain slowly decreases, resulting in some memory loss there. Also, the structure of the brain and the cell processes there are also altered. I'll post papers when I get them done...I just felt the need to post this because I feel everyone should know what I know and I want people to age well! lol Sorry if there are typos.
Oh and I didn't paraphrase anything really, so I got the info from the book Physical Dimensions of Aging, by Waneen W. Spirduso, Karen L. Francis, and Priscilla G. MacRae
Take-Home-Message-Exercise is good for every body system.