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October 28, 2006

Exercise and CR

A new commenter, Matthew, posed a question about CR and physical activity, so I'm reposting an excerpt from an old entry where I addressed the question. First, here's Matthew's comment (welcome Matthew!)

Hello Hello,

I have inadvertantly caught many different media sources talking about this new "live forever diet". I couldnt help but grab "The New Yorker" or whatever it was called off the shelves and read the article in its entirety. Thank goodness some people just don't put things back where they belong, or I would never have read it (I found it where snowboarder magazine should have been). I'm just curious, everything sounds great except for, it seems that there isn't much room for physical activity (it was a vague article mind you). I don't want to post anything really negative but I would really like to read a discussion on this or even be a part of one. The article posed a very interesting view but one I am really striving to get a mental grasp on because it spoke of loosing muscle and bone. I remain interested but for now it seems a totally mechanical and foreign idea. This rigorous control in your life day in and out seems contradictive to fun.

Don't worry folks, I'll address the last sentence later on, but in the meantime, here's a basic illustration re: exercise and CR, pulled from an entry last January.

Let's say that we have a hypothetical person who is interested in healthy life-extension. Let's call her Beth. Beth is 20, she's full grown to whatever height she's going to be, and she's having so much fun that she wants to live as long as she possibly can. So she's making some decisions about her life.

She finds out about CR. She decides to do it. Slowly over a period of a year or two, she loses weight very gradually and uses nutritional software and a postal scale to weigh and measure her food exactly. She continues to lower her calories while keeping up an exercise regimen of running about twenty minutes a day and some weight lifting for bone health. She eventually hits amenorrhea due to low body fat or whatever, and she doesn't mind because she doesn't want kids anyway so not being able to get pregnant at this particular moment is actually a plus. She has sex every day because she read in GQ, a most reliable source on the topic, that having sex every day adds eight years to your lifespan. Her partner, while skeptical of the scientific validity of the study in question, is happy to go along with the program.

Beth's trainer at the gym suggests that she train for a weight lifting competition, and Beth says, sure, why not? So she begins to train, but quickly realizes that if she's going to build more muscle and burn more calories, both through the exercise itself and because muscles burn more calories just hanging about, she's going to have to eat more.

Beth's main goal is the longest, healthiest lifespan possible. She started young. She is religious about her very low, carefully monitored calorie intake and nutrition. She rarely skips a day of having sex, and if she does due to travel or whatever, she is careful to make up for it the next day.

Beth decides to stick with her good-enough-for-bone-and-cardio-health exercise routine, but not to go for the power lifting competition. Cause she'd have to eat more Calories, and in the end, lower calories, not bigger muscles, are what seem to be causing the lifespan extension.

Now I'd just like to make it clear that I am not Beth, and Beth is not me, no matter how similar we may appear to be on the surface. Beth, like Cindy, the made-up protein guzzling ad lib woman from a few months back, is a fictional character, created to prove a point.

The point is, if life-extension, that is, living as long as possible, is your goal, you must exercise enough to make your bones and your heart happy, but beyond that, you're wasting your calories.

Now I personally find plenty of ways to consume more calories than I really need to without exercising a ton, and skipping a power lifting competition is no sacrifice for me. But for some CR practitioners, like Kenton the CR'd surfer boy, it's a serious concern. We all have a variety of goals, and sometimes our goals are in competition with each other. My struggles are a little less heroic: Goal 1: Live as long as possible. Goal 2: Create a low carb margarita. Compromise!

I think the most important thing is that we pursue our goals with as much knowledge as possible. We can get tremendous support and advice from each other, even when our goals are different. For example, MR has helped me improve my diet and supplement plan, and he isn't in the slightest bit interested in a low carb margarita. We compromise.

Posted by april at October 28, 2006 6:33 AM


Can you address the issue of those with larger body masses naturally and CR? It seems that someone like me, with a naturally large frame and big muscles, should not try to lose too much weight. I think I can tell the difference when I look at naturally slender people vs people who have dieted to the point that their joints look large. How does a person tell what their optimum calories are for their natural size?
Also, does it become easier over time to do CR? All the weighing of food and worrying would cause a lot of stress to someone like me, who was put on 'diets' as a teenager when I didn't need them. The emotional issues associated with food--how do you CRers solve them?
I don't think I can ever do CR because of my past history with my diet being regulated by my mom, etc. I'm doing well with trying to eat better but not obsess about calorie numbers, and I've lost 30 lbs this way.

Posted by: Janet at October 30, 2006 9:19 AM

I will add here that there are other benefits of exercise beyond heart and bone health. Regular exercise can contribute to good mental health and help manage blood sugar levels. And of course when we reach those older ages, flexibility and balance are essential to avoiding debilitating falls and fractures.

Oh yeah, and there *is* a low carb margarita mix out there (google it). It's not bad, but I like to punch it up with a little extra lime juice as it's a bit too sweet and light on the sourness. I have no idea about the life extending/shortening qualities of tequila though!

Posted by: jj at October 30, 2006 11:31 AM

Hi - this is a v interesting blog, thanks!

I'm interested in the exercise vs calories issue. I suspect I'm probably not sufficiently motivated for full-on CR anyway at the moment, but I'm doing some investigating, hence arriving at your blog, and for me, this would be one of the main problems. I do quite a lot of cycling (my commute is 6 miles each way daily, but I also enjoy distance cycling). Enough to burn up a fair few calories when I'm doing the distance stuff, at least, & probably the 12 daily miles is enough to have an effect in terms of CR (i.e. would affect the level I could cut to, if I were going to do that).

Anyway, I was wondering to what extent the animal studies which have demonstrated the age-extension effects of CR in mammals have also looked at how that interacts with exercise? I know that in most cases lab animals lead a pretty sedentary existence, so am wondering whether this has been explicitly addressed. You indicate above that there's evidence that gaining muscle per se doesn't affect lifespan. But can calories burnt in exercise cancel out calories taken in? i.e. if Rat A consumes x cal/day, & sees life-extension effects, & Rat B consumes x+y cal/day, but burns up y extra cal in zooming round an exercise wheel or whatever, what is the difference between the life-extension effects?

(if you know of any studies you can point me at, or any useful resources I could go hunting through, that would be great!)

(of course, there are as you say other issues with what goals you prioritise; e.g. cycling for me has many mental & physical health benefits. But I'm interested in the data available).


Posted by: Juliet at October 31, 2006 3:49 AM

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