Wednesday, April 08, 2015

Exercise doesn't help much

Medical researchers tend to get very excited even when they detect a very small effect of something.  Below is such a case.  When everything was controlled for in their analyses, they found a pathetic .66 hazard ratio ("the adjusted hazard ratios for all-cause mortality were 0.66").  Statisticians don't usually conclude that something real is going on until the ratio exceeds 2.0.  So the lifespan benefits of taking regular exercise are somewhere between tiny and negligible.  Pity that.

Effect of Moderate to Vigorous Physical Activity on All-Cause Mortality in Middle-aged and Older Australians

By Klaus Gebel et al.


Importance:  Few studies have examined how different proportions of moderate and vigorous physical activity affect health outcomes.

Objective:  To examine whether the proportion of total moderate to vigorous activity (MVPA) that is achieved through vigorous activity is associated with all-cause mortality independently of the total amount of MVPA.

Design, Setting, and Participants:  We performed a prospective cohort study with activity data linked to all-cause mortality data from February 1, 2006, through June 15, 2014, in 204 542 adults aged 45 through 75 years from the 45 and Up population-based cohort study from New South Wales, Australia (mean [SD] follow-up, 6.52 [1.23] years). Associations between different contributions of vigorous activity to total MVPA and mortality were examined using Cox proportional hazards models, adjusted for total MVPA and sociodemographic and health covariates.

Exposures:  Different proportions of total MVPA as vigorous activity. Physical activity was measured with the Active Australia Survey.

Main Outcomes and Measures:  All-cause mortality during the follow-up period.

Results: During 1 444 927 person-years of follow-up, 7435 deaths were registered. Compared with those who reported no MVPA (crude death rate, 8.34%), the adjusted hazard ratios for all-cause mortality were 0.66 (95% CI, 0.61-0.71; crude death rate, 4.81%), 0.53 (95% CI, 0.48-0.57; crude death rate, 3.17%), and 0.46 (95% CI, 0.43-0.49; crude death rate, 2.64%) for reporting 10 through 149, 150 through 299, and 300 min/wk or more of activity, respectively. Among those who reported any MVPA, the proportion of vigorous activity revealed an inverse dose-response relationship with all-cause mortality: compared with those reporting no vigorous activity (crude death rate, 3.84%) the fully adjusted hazard ratio was 0.91 (95% CI, 0.84-0.98; crude death rate, 2.35%) in those who reported some vigorous activity (but <30% of total activity) and 0.87 (95% CI, 0.81-0.93; crude death rate, 2.08%) among those who reported 30% or more of activity as vigorous. These associations were consistent in men and women, across categories of body mass index and volume of MVPA, and in those with and without existing cardiovascular disease or diabetes mellitus.

Conclusions and Relevance:  Among people reporting any activity, there was an inverse dose-response relationship between proportion of vigorous activity and mortality. Our findings suggest that vigorous activities should be endorsed in clinical and public health activity guidelines to maximize the population benefits of physical activity.

JAMA Intern Med.

Posted by John J. Ray (M.A.; Ph.D.).


Doom said...

Actually, if they look at what most people do in order to exercise regularly, especially the muscle-heads, they would find that exercise is bad. They just can't bring themselves to the idea. The boomers, still in charge of academia, have this fatal attraction to youth. I can just picture a bunch of old people, who believe themselves to be babies, reverted to youth, drowned in that pool. Wishes might come true, perhaps just in the mind, but enough lust and it can seem real.

Immortality, without sin, is another such illusion, at least in this life and this world. But they won't quit trying to find it until they are in hell. No lies there. Yeah, surprising, but true. Then again there are no lies here, only make-believe. Which is why liberals choose to murder any who doesn't believe what they preach.

Wireless.Phil said...

On ABCnews yesterday.
Saying it will keep you young or some bs like that, I wasn't really paying attention to it.

I can hardly walk more than an hour without terrible back pain, I'm sure not going to exercise.

Wireless.Phil said...

Just this morning I was reading about a French Canadian who lived to 115.
What kind of life can you have at 115?

In the site below, some have lived to 122 years old, that's crazy.


eXTReMe Tracker