Recker says that researchers speculate, however, that it has to do with exercise triggering osteocytes (the most mature bone cells) to instruct bone-building cells called osteoblasts to increase bone formation.
Wards off diabetes
According to Gerald Shulman, a cellular and molecular physiologist at Yale University School of Medicine in New Haven, Conn., exercising may prevent and even reverse type 2 diabetes.
Diabetes type 2 is a disease in which the body begins to ignore or fails to produce enough insulin (a condition called insulin resistance). If muscles and other tissues cannot absorb glucose from the blood, nerve and blood vessel damage ensues, paving the way for heart disease, stroke and infections.
"We've shown that in insulin-resistant individuals… build up of fat leads to biochemical reactions that interfere with the glucose-transport mechanism [leading cells to block the activity of insulin]," Shulman says. But physical activity helps reverse this process. He notes that when someone runs, cycles or does other vigorous exercise, muscle contractions ramp up production of adenosine monophosphate-activated protein kinase (AMPK), an enzyme that promotes the breakdown of the fats interfering with the cells' glucose transporters.
"It is very likely that there are differences in the extent to which individuals respond to exercise, just as there are in responses to medications," says Ronald Sigal, a clinical epidemiologist at the Ottawa Health Research Institute in Canada. Leon agrees, pointing to research demonstrating that exercise leads to varying decreases on visceral body fat (the fat surrounding organs), one of the key risk factors for developing type 2 diabetes.
Makes you smarter
Researchers have long believed that exercise boosts smarts but there was not any hard scientific evidence until a few years ago. Now, says Fernando Gomez-Pinilla, a neurosurgery professor at the University of California, Los Angeles, it's known that exercise increases levels of some molecules in the brain that are very important for cognition.
One such chemical is brain-derived neurotrophic factor (BDNF), a molecule that promotes the growth and survival of brain cells as well as communication between them. Studies in rats show that physical exercise boosts BDNF levels in the hippocampus, a brain structure critical for learning and memory formation, which in turn helps them remember how to navigate their way through underwater mazes. "The more exercise, the more changes in the brain; we found almost a linear relationship," Gomez-Pinilla says. "If we block the BDNF gene, we block this capacity of exercise to help learning and memory."
Numerous studies suggest that fitness enhances cognition in humans as well. A randomized clinical trial published recently in the Journal of the American Medical Association found that people 50 years and older with memory problems scored higher on cognitive tests after a six-month workout regimen. Those study participants assigned to exercise programs scored 20 percent higher than their sedentary peers at the end of the six months, and maintained a 10 percent edge one year after the trial ended.
But skeptics warn that not enough research has been done to confirm a link between exercise and human brain power. A recent review of studies on cognition in older adults (primarily those age 65 and older) by Dutch scientists published in the Clinical Journal of Sport Medicine concluded that "beneficial effects of various exercise programs on aspects of cognition have been observed in studies among subjects with and without cognitive decline. The majority of the studies, however, did not find any effect."
Weight Loss
The relationship between exercise and weight loss is complicated. Contrary to popular belief, working out at the gym every day will not necessarily lead to weight loss. "It is reasonable to assume that persons with relatively high daily energy expenditures would be less likely to gain weight over time, compared with those who have low energy expenditures," write the authors of the American College of Sports Medicine (ACSM) and the American Heart Association's (AHA) 2007 guidelines. "So far, data to support this hypothesis are not particularly compelling."
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26 Comments
Add Commentin nature no animal E X E R C I S E S .. It is A C T I V I T Y that is the factor that runs the complete body physiology. see a caged gibbon swinging tirelessly without end. even lazy or aged humans can keep physically and mentally busy life long. but exercise is limited to few persons for short periods of life.
Reply | Report Abuse | Link to thisYou didn't say anything with this post. What exactly is the difference between exercise and activity? Is exercise not an activity? Is doing an activity not giving you exercise? What was the point of acting high and mighty if you're not going to say anything?
Reply | Report Abuse | Link to thisThe great thing about exercise is that it can extend your life up to 7 years and you will die in perfect health with a perfect body unlike sedentary people who die with their body a wreck, a cesspool of gastrointestinal spackle and arteriosclerotic gunk. But exercise cannot reverse Darwinism which dooms everybody.
Reply | Report Abuse | Link to thisFor some of us, regular exercise & strict diet have only a minor effect on cholesterol numbers. What's been most helpful to me, though, are the articles & studies found at cholesterolscore,com . It seems that therapeutic doses of niacin, which has been used & studied since the 1950's, has also done what statin drugs like Crestor promise. From lowering LDL to improving C-reactive protein levels, to lowering triglycerides, to enlarging lipid particle size, to increasing longevity, no other medication has been found to be as effective as niacin. Niacin, though, is less expensive than aspirin.
Reply | Report Abuse | Link to thissorry, the website is www.cholesterolscore.com
Reply | Report Abuse | Link to thiswhere are you from?
Reply | Report Abuse | Link to thisIt is unfortunate that food is often regarded in a religious manner. In response to eating healthy, one often exclaims that they would be unhappy in denying themselves certain foods. But the irony in that is that eating unhealthy foods contributes empty Calories and possibly increasing weight size which can lead to bouts of depression when your poor habits have produced an unsatisfying physical image; moreover, it leads to a wider array of other health problems and so the idea that one is happy when eating foods that are unequivocally bad for you is an idea rooted in ignorance. See, ignorant parents condition their children to eat poor foods and the children, usually staying ignorant, never shrug off the poor eating habits. This conditioning is what leads people to treat foods in a religious manner and perpetuate this cycle of poor health. It is a great misfortune to humanity that technology has enabled us to become so dangerously ignorant that we eat ourselves and live sedentary lifestyles until we have accrued some debilitating disease at which point a change in eating and activity habits may be too late. And yet it is commonly held that us humans are more special than other organisms but those other organisms aren't so dumb as to workout that there is nothing more enjoyable to life than eating whole foods and exercising for great health. Somewhere in the past 100 years the "developed" societies have lost the ability to work that out.
Reply | Report Abuse | Link to thisThe ONLY thing that makes you feel better? Yikes! My condolences.
Reply | Report Abuse | Link to thisThis article missed a very important effect of exercising. Exercising relieves your stress, which can also increase your lifespan and improve your health.
Reply | Report Abuse | Link to thisInteresting...but did we really need a study telling us that exercise was actually healthy for us?
Reply | Report Abuse | Link to thisqUasi:
Reply | Report Abuse | Link to thisClarification:As a treatment for depression, exercise is the only thing that really makes me feel better. There are clinical studies which support this effect. In addition, while young at heart, I'm an old fart so my body responds very favorably to exercise and functions much better. U yungs don't have to worry about that but I'm almost 60 and people think I am 40 years old.
I tried niacin and developed the most horribly itching rash that even persisted after lowering the dosage.
Reply | Report Abuse | Link to thisAre there any studies of the long term effect of high dosages of niacin?
exercise is an absolute necessity
Reply | Report Abuse | Link to thisHuman Health and the optimization of the same involves an complex interaction amongst all body systems. As in a game of chess, the utmost goal is to protect the King, that is, to maintain life. Appropriate exercise, through the utilization of all body systems, maintains the functionality of the same individually and collectively because of the requisite interaction of the same. Individual pieces, such as a Knight,Bishop,Queen, and/or Rook, can be seen as representing different organ systems. The effectiveness of a game of chess, outside of the prime job of protecting the King, similarly include time, space, force, and pawn organization. Similarly, health optimization, through exercise, with a little imagination, can be related to the same. Thus, appropriate excercise successfully addresses complex health optimization means and objectives which, without using the aforementioned generalizations, would be extremely tedious to detail. The Greek-Roman ideal of "Mens Sana En Sana Corpore", "A Sound Mind in a Sound Body", expresses the same appropriately and succintly.
Reply | Report Abuse | Link to thisWell, that last part is misleading. The statement that limiting caloric intake "trumps" exercise is pretty darned ignorant of the facts!
Reply | Report Abuse | Link to thisI started cycling 3 x week around 10 years ago. It took just 12 weeks to get to the point where I could ride 3+ hours at 80% of max heart rate. (I read a book about conditioning for cyclists past age 50.) Progressively increasing the "work" done per unit of time over that period was fairly easy and never caused any injury.
Calories burned: It's true that walking burns a few extra calories as said. But riding a bike (15-20 mph) for an hour will get an average size person burning calories at over 300 calories / hour! I reach close to 500 calories per hour. (And ate like a pig after every ride - like most "advanced" cyclists joke about doing.) Even so - I lost weight while lowering my at-rest heart rate to it's lowest lifetime rate.
Only drawback: 3 x 3 hours / week is 9 hours. That's well above the time invested if you follow the recommendation in the article. Admittedly, it's hard to find that much time every week. But it is certainly worth it to try!
But notice: once you've reached a higher physical fitness: Spending just 1 hour / day x 3 per week burns 900 to 1500 calories per week. At the level, it would take only a minor downward adjustment of food intake to lose substantial weight in a short time. "Maintenance" over the long haul is much easier too. (No "bounce back" weight gain.)
The rather tart response made to the comment that activity was important rather than exercise was, I beleive rather a knee jerk response. I read the original post as suggesting that the general level of activity in someone's life was more predictive of beneifit than what they might undertake in an hour or two per day i.e. that the poster was suggesting that someone who sat at a desk all day and then did exercise may well be at a disadvantage vis-a-vis a sugar cane cutter for example. Whether the cane cutter would benefit from extra exercise on top of the general olevel of activity is to me an interesting point.
Reply | Report Abuse | Link to thisThe rather tart response made to the comment that activity was important rather than exercise was, I beleive rather a knee jerk response. I read the original post as suggesting that the general level of activity in someone's life was more predictive of beneifit than what they might undertake in an hour or two per day i.e. that the poster was suggesting that someone who sat at a desk all day and then did exercise may well be at a disadvantage vis-a-vis a sugar cane cutter for example. Whether the cane cutter would benefit from extra exercise on top of the general olevel of activity is to me an interesting point.
Reply | Report Abuse | Link to thisThe bottom line: couch potatoes may applaud the exercise naysayers but the bulk of research suggests that workouts make us physically and perhaps mentally healthier.
Reply | Report Abuse | Link to thisDid we need a four page SciAm article to tell us that? :-P
crad - How remarkably ignortant of you. A wide variety of animals do over eat when they have the chance. If you knew anything about ecosystems and animals you would know this. You also missed the boat when you indicated that the last century somehow caused us to be ignorant and start eating unhealthy food. Humans have eaten unhealthy foods for millenia. The primary change of the industrial age is to cause people to not have to expend as many calories and to add dangerous chemicals to our food and that almost exclusively is the cause of our health and weight problems. We are not more ignorant, we are far less ignorant. You, however, are an exception.
Reply | Report Abuse | Link to thisStevlich - Darwinism? Really? People didn't die before the theory of evolution? The term you are looking for is mortality. It has nothing to do with Darwin at all. Why did you bother to post? You botched the science completely. Were you trying to say it is better to die now as a fat unhappy lout than to live healthy and active? What was the point you were trying to make?
Harleyman - Woot! You win the prize! Creator had limited impact on my cholesterol and triglycerides levels and diet and exercise had next to none. I read that niacin might help so I started taking it. It made a big difference!
The only caveats are that the delayed release niacin is useless and the affect of niacin is like a sine wave. It causes a change but 8 hours later is wears off and the body rebounds to levels as much worse than normal as the 8 hour improvement. This means that you have to take the niacin 3 times a day and experience the unpleasant side effects each time.
There is a prescription called Niaspan that claims to do the burst release repeatedly over a 24 hour period but it is insanely expensive and I have not been on it long enough to know if it really works as promised.
I do exercise by biking or jogging several times a week but the more I exercise, the more weight I gain. I usually get very painful hunger pangs about 45 to 60 minutes after heavy exercise. If I don't eat then I get very tired and mentally fuzzy. Yes my doctor checked and said I am not diabetic.
I wish there was an edit feature for our own posts because I spelled Crestor as Creator and I can't fix it.
Reply | Report Abuse | Link to thisIntelfam - Thanks for pointing that out. I entirely missed it and was also reacting to that post rather harshly but now it makes sense to me. The problem is likely more one of translation than one of intended meaning.
Being a mouse potato (I am an CAD draftsman and the IT department for a small electronics firm and when I go home I spend all my time in front of the computer) I am morbidly obese.
Reply | Report Abuse | Link to thisI am trying to exercise and lose weight not to extend my life but to improve the quality.
Being so fat prevents me from doing a lot of the things I want to do as well as being a block to having a social life.
Exercise a the tool that replaces the strenuous activity it took to survive before hard labor was replaced with machines.
Our bodies are designed (whether by a creator or evolution) to be active.
We start breaking down when we are not active enough as noted by all the medical and mental issues already mentioned.
I believe that the only reason the study showed such a small difference in lifespan was that we have the medical technology to keep us going even as our bodies are deteriorating due to abuse/ lack of maintenance.
If we had two groups one that exercised (or were active in other ways) and one that was composed of couch/mouse potatoes and prevented both groups from getting any kind of medical care the lifespan difference would be far more dramatic.
I don't doubt that many animals do over eat when they get the chance(for survival reasons) but it is kept in check by physical activity. Hence, the combination of over-eating and living a sedentary lifestyle is not a winning strategy for mammals in particular. And on the topic of eating unhealthy foods for millenia, that could hardly be the case. Humans, before the advent of industry got a stranglehold on food production, had pretty much paleolithic style diets. What is that? Basically, if it doesn't go bad within a week, you don't need to be eating it. And on the note of chemicals linked to weight gain, unlikely. Excessive energy input leads to weight gain. If you don't balance your energy input with your energy output, and the input exceeds the output, you will gain weight. There is no magic, there is no voodoo. and yes, you seem to be rather ignorant of this if you think that you gain more weight as you exercise. It is very simple: input/output is a ratio. Input is the energy acquired from foods, output is the energy expended through physical activity. If your output exceeds your input for a set of months, you WILL lose weight. Exercise doesn't magically make you gain weight; and while exercise has the potential to build muscle and increase your pre-existing muscle fibers, it doesn't mean that this will happen. The reason is that energy is required to build muscle and if you leave yourself in a Caloric deficit(i.e., lose weight), you will not lend your body the extra energy needed to increase muscle mass(and hence, increase weight.).
Reply | Report Abuse | Link to thiswell, actually,
Reply | Report Abuse | Link to thiswe were meant to move
Our ancestors "exercised" i.e. did hard physical labour and had much shorter lifespans than us sedentary folk. Yes, animals don't "do exercises" and turtles and elephants don't much at all physically yet they have the longest lifespans in the animal kingdom. I'm not saying that sitting around over-eating and watching TV is good for you, what I am saying is that maybe exercise is a little over estimated as a source of good health.
Reply | Report Abuse | Link to thisI agree that if you take in more energy then you expend you will gain weight - however - some people have faster metabolisms and some have very slow and there are reasons for that - less muscle (less exercise) but also chemicals affect metabolism in various ways - they block thyroid receptors, clog the liver - lots of evidence for this. Considering all the fitness centers and exercise equipment and all the diet books and diet centers yet people are getting fatter there has to be more to it. Personally I'm not overweight but was until I started on thyroid hormone yet I still don't lose weight on 1600 calories along with exercise once I reached a certain point. I'm 5'9 1/2" tall and if just eating less calories and doing some exercise was the answer I should be THIN instead of the top of "normal" which is NOT the ideal weight for my frame! And I know people that exercise a lot, are very careful what they eat and are still overweight! I also know some that have their house full of junk food that they eat and they are thin (though not as many)! Obviously there are other factors at play in the obesity epidemic and chemicals, toxins, processed food, pollution and even prescription drugs to mask every symptom people get rather than find the real cause of their illness has to have something to do with it. It's very easy for people that are blessed with normal metabolisms to assume everyone that is overweight is sitting around eating garbage all day. As one who has struggled most of my life and at times lived on an average of 1400 calories a day while remaining overweight I know this is not always the case!
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