Muscle mass extends life expectancy
If you do heavy physical work or weight training, you'll not only make your body more muscled and stronger, but you'll also make it last longer. Muscle mass extends life expectancy write researchers at the David Geffen School of Medicine in the American Journal of Medicine.
Body weight & mortality
Researchers used to think that overweight elderly people had a higher risk of dying, but recent studies have shown that both overweight and underweight elderly people are more likely to die. More and more epidemiologists are therefore coming to the conclusion that it's not bodyweight that determines how long you are likely to live, but lean body mass.
In other words: the muscles.
Preethi Srikanthan tested this theory by examining data on 3695 over 55s gathered for the National Health and Nutrition Examination Survey III.
Srikanthan followed the participants from the period 1989-1994 until 2004. When the study started the men were over 55 and the women older than 65.
Srikanthan noted which of the participants died in the 10-16-year period.
There was no relationship between the participants' amount of non-muscle mass and their survival chances, Srikanthan discovered when he divided the participants into four equal-sized groups (quartiles) on the basis of their non-muscle mass, and then calculated their mortality risk.
The figure below shows this.
But when Srikanthan divided the participants into quartiles based on muscle mass, he did find a relationship. Participants with lots of muscle mass were 20 percent less likely to die than participants with little muscle mass.
Srikanthan is not sure how muscle mass increases our survival chances. Perhaps it protects against high glucose levels, perhaps it reduces the amount of dangerous fat in the body, or perhaps muscles produce protective substances. But he does have a word of advice.
"Get up and start moving", the researcher said in an interview with Christopher Intagliata of Scientific American. [scientificamerican.com Mar 20, 2014] "Focus on trying to maintain the maximum amount of resistance training that you can, and stop worrying so much about dropping calories."
Am J Med. 2014 Jun;127(6):547-53.
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