Too Much Exercise May Not Be Better Than a Sedentary Lifestyle

jones_supa writes: The importance of exercise has been arriving in spades for geek culture. However, when approaching extremes, a point is reached where vigorous jogging erodes some of the benefits light jogging has over a sedentary lifestyle. "Long-term excessive exercise may be associated with coronary artery calcification, diastolic dysfunction and large artery wall stiffening," wrote lead author Peter Schnohr of Copenhagen's Frederiksberg Hospital in a Danish study (abstract). Although previous research has found that physically active people have at least a 30% lower risk of death compared with inactive people, the ideal amount of exercise remains somewhat uncertain. In this study, strenuous joggers — people who ran faster than 11 km/h for more than 4 hours a week; or who ran faster than 11 km/h for more than 2.5 hours a week with a frequency of more than three times a week — had a mortality rate that is not statistically different from that of the sedentary group. Medical journalist Larry Husten notes that this study, while interesting, should not be taken as the final word on the subject.

Comments

Re:I'll save science billions of dollars in resear

[Anonymous Coward]

The doctors told him that pretty much anyone who jogged that much has to get new knees.

Running is a complex biomechanical activity. Most people I see running are not running with biomechanically-correct form. This probably stems from lack of knowledge of how to run correctly, lack of core strength to run correctly, shoes that do not fit their physiology and personal running form, etc., etc.

Since most people run with poor form, it's not a surprise that most people that jog require knee replacements.

Running, when done correctly, produces minimal stress on knee joints, even at 10+ mph.

Internet hyperbolic echo chamber strikes again...

[Anonymous Brave Guy]

2) Measure things until one of the outcomes reaches "statistical significance".

Look at the small number of participants shown in the original data here, and the conclusion that is being echoed all over the Internet seems dramatically overstated. The original authors acknowledged this and called for further research, as did the editorial accompanying publication, but of course that hardly gets mentioned in all the Internet echo chamber "don't do too much exercise, you might just as well slob around on the sofa" rhetoric.

I can't find a publicly available primary source to cite, but it looks like only a little over a hundred "strenuous" joggers were included in the study, and of those only two actually died. The remaining ones could go jog their normal route and still not travel the length of the error bars here.

Re:Internet hyperbolic echo chamber strikes again.

[Albanach]

The Forbes article linked in the summary is telling:

They point out several very important weaknesses in the study. First there is the general issue that this is just an observational study. There are a multitude of differences between the different groups in the study, and it is impossible to know with any certainty whether the jogging dose had any important causal relationship with the deaths that occurred in the study. Of course the researchers attempted to correct for many of the known differences but this is a highly imperfect science at best. And this was not a best case scenario. The mean age of the non-joggers in the study was 61.3 years while the mean age of all the joggers in the study ranged from the late 30s to the mid 40s. So this isn’t just comparing apples and oranges, it’s comparing a young juicy apple with a shriveled old lemon.

But even if it were possible to compare the groups and adjust for the differences there would still be another insuperable problem. The study simply had no statistical power to detect differences between the jogging groups. Although there were 128 deaths among the 413 non-joggers there were only 17 deaths in all the 1,098 joggers, including only 2 deaths among the 36 strenuous joggers. The authors calculated that those 2 deaths represented a two-fold increase in risk for the strenuous joggers compared to the non-joggers, but the enormous confidence interval, ranging from less than half the risk to an 8-fold increase, illustrates the futility of obtaining any sort of reasonable estimate of risk based on so few data points.