13 replies to this topic

[forever freedom]

This study leaves no doubts that CRed mice that did not exercise were healthier than mice with normal diets that exercised regularly. What about CR + exercising? Would it bring significant added benefits to people already on a CR diet?

[Johan]

Well, if you are to exercise while doing CR, you would obviously need to consume more calories per day than if you didn't exercise, since you spend more energy. So it's really a balance between degree of CR and amount of exercise. Call it "ratio of CR to exercise" if you will. The question would then be: at what ratio do you gain the most benefits?

You could construct a diagram like this:

with the height of the curve at a specific point being the amount of benefit you get at that precise ratio between CR and exercise.
We know the starting point (only CR, no exercise) and the end point (no CR, only exercise), and we know that the starting point is higher on the benefit scale than the end point, but we don't know how the curve looks between those points. Perhaps it's like the green curve, with maximal benefits standing to be gained when only doing CR to a high degree, and not exercising. Or maybe it's like the red curve, with the maximum benefits coming with a bit less CR and a bit more exercise.

Are there any studies on this?

Edited by Johan, 15 May 2008 - 06:53 PM.

[forever freedom]

Yes that's what i was thinking about. The more exercise you do, the more calories you have to consume, and the more calories you consume, the less benefits you get from CR. So it's really a matter of knowing what's the perfect balance, or a matter of whether exercise is really needed for someone on CR.


edit: i like this graphic. Now we just need the info to make it be right =/

I don't think there are enough studies to give us an answer right now. But since these studies with mice aren't very expensive, someone could do them to find the ideal lifestyle, whether it's a combination of CR with exercise or just CR.

Edited by sam988, 15 May 2008 - 06:58 PM.

[Johan]

Mice studies would be nice. But mice might have a different optimal CR to exercise ratio than humans. Perhaps (this is just speculation) the fact that they have fewer DNA repair pathways than humans (sadly, I can't find the source of that information) might mean that have a higher optimal ratio than humans since they are less able to cope with oxidative damage, and thus benefit more from CR since it means less oxidative damage.

Edited by Johan, 15 May 2008 - 07:13 PM.

[VictorBjoerk]

Why should exercise at all have a true antiaging effect?

[Johan]

I guess the main reason that exercise "delays aging" is that it lessens the risk of succumbing to a number of diseases and other conditions since your body is better equipped to handle them. For example, a stronger skeleton means less risk of bone fracture.

[Mind]

I wonder if a CR person just sat around on the couch and watched TV all day, if they would have cardio-vascular problems at some point in their life. Such as, would they have a heart attack if all-of-sudden they found themselves in danger and had to sprint for a half mile or had to shovel a bunch of snow (lots of people have heart attacks shoveling snow)? That being said, almost all the CR people I know do get a healthy amount of exercise, would be dumb not to.

Anyway, at the most basic level, it seems CR works because you end up burning fewer calories and thus you have less damage accumulate throughout life.

[VictorBjoerk]

I've heard according to statistics that lifelong exercising people tend to live about 10 years longer than average but their mortality curve is quite straight.They manage to escape from many of the typical diseases associated with old age but still somehow dies.

[VictorBjoerk]

Wouldn't it be most optimal when on CR to just do daily activities for "exercise".If they are complete couch potatoes their health may detoriate but why should they exercise more than normal daily walking and activities like gardening etc....

[VictorBjoerk]

Do you think constantly exercising people with healthy eating habits like Jack Lalanne and Madonna seem to have aged more slowly than normally or do you think they look their age but just more fit.What are your opinions?

[Johan]

Anyway, at the most basic level, it seems CR works because you end up burning fewer calories and thus you have less damage accumulate throughout life.

From what I have read, CR also enhances some DNA repair pathways, so the damage that does occur gets fixed a lot better.

Anyway, I think the red curve in my diagram is a closer match to reality than the green one - mostly CR with light exercise (like daily activities - walking, biking, etc.). I imagine that a totally sedentary person would be worse off than a reasonably fit one, even if the former was doing CR to a greater extent than the latter - as long as the difference isn't too large. At some point, the benefits of exercise seem to become outweighed by the fact that you have to eat more to keep it up.

Edited by Johan, 15 May 2008 - 10:09 PM.

[forever freedom]

I have found an interesting study on that topic.

John O. Holloszy. Mortality rate and longevity of food-restricted exercising male rats: a reevaluation. Journal of Applied Physiology Vol. 82, No. 2, pp. 399-403, February 1997 EXERCISE AND MUSCLE
http://jap.physiolog...e832a59843c#B16

At least they conclude that exercising is not harmful to CR:
“The present results show that exercise does not interfere with the extension of maximal life span induced by food restriction. The beneficial effects of food restriction and exercise on survival are not additive or synergistic in male rats.“

However, the study cannot answer the question whether restricting calorie intake through exercise is as effective as restricting food intake, because their test animals gained no benefit from >30% CR:
"It is therefore of interest that the 30% food-restricted runners in group C and the paired-weight sedentary rats in group D, which had to be food-restricted by ~50% to keep their body weights the same as the runners', had similar survival curves despite the difference in degree of restriction. Interpretation of this finding is complicated because, although food intake was different, the relative caloric deficit and the degree of growth retardation were similar in the food-restricted runners and the paired-weight sedentary rats. However, our previous study included both ~30% and ~50% food-restricted sedentary groups, and their survival times were also not statistically significantly different"

Regarding the question of CR and exercise being synergistic, I don't think one can draw conclusions, from a simple rat study, like "The beneficial effects of food restriction and exercise on survival are not additive or synergistic in male rats.“ - thus they won't be in humans.
We exercise in a more sophisticated way than wheel-running rats and the study merely included endurance type of training, whereas strength training could be much more beneficial for human CR practitioners (bone density, strength, etc).

Yea this is really a delicate issue where we don't have definite answers yet. Partly because we don't even know vert well how and where in the body CR works and what triggers it; our science is still so primitive...