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.
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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.
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.