An interesting study regarding the decline of cardiovascular capacity when minimizing activity level to the least amount possible. (www.ahajournals.org)

submitted 1 year ago* (last edited 1 year ago) by forestG@beehaw.org to c/science@beehaw.org

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For the initial evaluations in 1966, 5 healthy 20-year-old male volunteers were assessed at baseline, spent 3 weeks at complete bed rest with no weight bearing allowed (similar to clinical treatment of acute myocardial infarction at the time), and then underwent 8 weeks of intensive endurance training. Cardiopulmonary function was evaluated by determining maximal oxygen uptake (VO2max) during stress testing to exhaustion, the gold standard measure of integrated cardiorespiratory capacity reflecting the capacity of the circulatory and respiratory systems to deliver oxygen to skeletal muscle during exercise, measured at baseline, after bed rest, and after endurance training, with results summarized in the Table.

[...]

These same 5 volunteers were studied 30 years later (1996) at baseline and after endurance training, with no bed rest exposure evaluated, with results previously published summarized in the Table. Contrasted with the 27% decline in VO2max with bed rest in the 1966 study, baseline VO2max had declined by 12% over the 30-year interval. Thus, 3 weeks of bed rest at age 20 years reduced cardiovascular capacity more than 30 years of aging.

While complete bed rest is a quite extreme case of inactivity, I think this is quite indicative of how fast our bodies deteriorate when we don't move enough during each day.

The study is not new, but I found about it recently and thought it was worth sharing.

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[-] TokyoMonsterTrucker@lemmy.dbzer0.com 6 points 1 year ago* (last edited 1 year ago)

5 subjects is such a tiny sample size as to be scientifically worthless. I wouldn't get too worked up about this study.

[-] forestG@beehaw.org 5 points 1 year ago* (last edited 1 year ago)

Tiny indeed, especially if it were to draw general conclusions. But it doesn't.

I am glad that you wouldn't get worked up about the fact that one of the most important markers of health of the human body quickly deteriorates when you don't move at all. I wouldn't either. The fact is so obvious that it should be common sense.

What is interesting in this study, is the follow-up, on those few people. Not just the very rapid decline of their cardiovascular systems shown initially, but the comparison of the decline shown 30 and 40 years later. Even if those 5 samples are outliers (maybe they are the worst cases, maybe they are the best cases, we can't know, 5 is too few), the comparison remains impressive.

But maybe its just me.

[-] TokyoMonsterTrucker@lemmy.dbzer0.com 2 points 1 year ago

Ah, it seems I misunderstood the initial summary. I read the whole article and it all makes sense now. Lesson: don't post at 3 am 😅

[-] forestG@beehaw.org 1 points 1 year ago

Well, I thought I should omit the first line of the introduction (which contains the number) for the same reason you pointed out in your initial comment. What kind of study has 5 person sample with pretty much no control? I debated myself (english is not my first language) whether I should use the word "study" in the title, or an another word, like observation or something. But they call this a study in their article. Besides, if taken at face value, it's not prompting people to do something unhealthy (moving a little more than zero), doesn't push some magic thinking towards a super processed food (or supplement, or drug), so ..

Not the 3 am, or stoned or whatever. Most of us have been there :P It's the "not going past the second sentence but posting a comment anyways" habit that feels bad to me.

[-] kirstierthanthou@beehaw.org 2 points 1 year ago

I am curious what the comparison would be to people who did not go through bedrest and were constantly active through the decades. 🤔 Either way it's pretty terrifying the potential impact office work will be on a portion of the population 😬

[-] forestG@beehaw.org 1 points 1 year ago* (last edited 1 year ago)

what the comparison would be to people who did not go through bedrest and were constantly active through the decades

I am curious too, but the more I look for such studies the more it becomes apparent that I won't find them. Looks like there is not much motive to study what prevents our health from deteriorating..

Well, at least people living away from urban environments, usually have a few examples of this. Active persons, refusing to remain idle for too long. You know.. that person who was still standing, fully functioning (well, with some arthritis :P) and able to tend to a garden in his 90ies?

the potential impact office work will be on a portion of the population

If jobs were good for us, we wouldn't get paid to do them.

You can work construction, be active all day, but end up with serious debilitating injuries of overuse. You can work in an office, and get all kinds of underuse issues.

As long as most of us have to work, we need to find ways to balance what our kinds of jobs do to our bodies. Long before we go to doctors for fixes, in systems that have already broken down. A very clear (and becoming more and more clear) example of this, is insulin resistance. The liver of an average person can hold something around 120g of glycogen, which is way more than most of sedentary people consume in carbohydrates daily. It doesn't take much before the system starts saying "no more triglycerides, all vital organs are cramped in here!" and starts doing all kinds of less than good compensations for the extra energy coming in from this metabolic pathway. Our muscles that hold that absorb glucose and turn it into glycogen do not share it with other body cells (like the liver does, i.e. by feeding the brain and all other body cells that require glucose through blood). If you don't move, they don't break it down to glucose and use it. If they are full, they don't absorb glucose from the bloodstream. So, even if they can hold like 500g of glycogen, how many meals of carbs before they are full? 2? 3? 4? Excess carbs from that point on become triglycerides (fat). It's such a simple concept to grasp..

What is sad, is that while usually kids do not have to work many of them stay inactive anyways..

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