Hi readers– I’ll be doing an occasional (roughly once a month) post on some of the latest research on physical activity, nutrition, longevity, fitness, and other health-related topics that appear on my radar screen. (Full disclosure: most of these studies came to my attention courtesy of Sam, who manages to sift through mounds of exercise and health information coming her way every day; thanks Sam!)
Today’s theme is exercise and longevity math: how does that add up again?
First up: news outlets announce new study showing that weight training can “take eight years off your body”(sez the Telegraph here), or (according to Women’s Health here) “can shed eight years off your biological clock”, or “give you the body of a person almost eight years younger”.
Okay, I have questions:
If the weight training is “taking eight years off my body”, is that in a good way or a bad way? Are we extending my life or making it eight years shorter? Ditto for the biological clock thing. These writers clearly didn’t learn much about ambiguity in language.
This reminds me of the oldie-but-goodie SNL skit where retiring nuclear power plant engineer (played by the late great Ed Asner) offers this parting advice: “You can’t put too much water in the reactor”. The remaining employees argue amongst themselves about whether he meant “don’t put too much water in the reactor” or “however much water you put in the reactor, it’s fine”. Language matters, folks.
And if I’m getting the body of someone eight years younger, do they then get mine? Do we get any say in this? I’m not feeling happy about this.
Linguistic concerns aside, what’s going on here? Women’s Health summarizes below:
The study examined the impact of weight training on ageing in a random sample of 4,814 men and women, aged 20 to 69, in the US. Researchers analysed the length of ‘telomeres’—the protective DNA caps at the ends of chromosomes… which prevent genetic material from unraveling or becoming damaged.
The study’s authors wanted to determine whether weight training could impact the length of these telomeres. They did this by taking blood samples from the participants and measuring the length of telomeres in their blood cells. Participants were also asked to report how often they engaged in ‘exercises to strengthen their muscles’.
‘In this national sample, 90 minutes per week of strength training was associated with 3.9 years less biological ageing, on average,’ the study reads.
But, if I go twice as often each week, I can extend my life by eight years, right? Well, no. This study is not causal– it’s just showing an association between weight training and telomere length. There are loads of behavioral or genetic or environmental factors which can help account for this correlation.
Is strength training good for us? I think the jury is in on this one: yes. Is it going to help us live longer? Dunno. Maybe? How much longer, and in what condition? No one knows.
What if you don’t happen to enjoy strength training? Maybe you prefer walking. Can you get some longevity bang for your walking buck? It would seem so, if our news media headlines are to be believed. “Daily walks could add more than 10 years to your life”, (according to Real Simple). Fortune Magazine ups the ante to 11 years. My favorite is this one from The Independent: “Just one hour of walk in middle age can add years to life”. That’s a pretty low bar, but okay– excellent! Good for us all.
Sorry, but it’s now party-pooper time. The actual study, published in the British Journal of Sports Medicine, took a look at different subsections of the population by level of physical activity (PA). They found that if all adults were as active as the highest quartile (25%), relative to PA, they could potentially live 5-ish years longer.
We’ve kind of known this for a while now, namely that the number one predictor of longevity around the globe is physical activity. Of course, this new study is very useful for nudging governments and health systems to fund more access to physical activity for all individuals throughout the life trajectory. We need more evidence and pressure on authorities to do just that.
But Fortune magazine and Real Simple– maybe y’all should stick to reporting on the latest in tech stocks and table decorating trends, respectively.
Thank you for taking on the task of shining a light on studies (and their media-claimed results) on a regular basis. We are so often bombarded with “news” that turns out to be misleading at best.
So now I’ll go all unscientific and say, for what it’s worth, that my very high activity levels made me the least out of breath of everyone in my tap class last night. I am the oldest there by about 20 years; the youngest is 16, others range from 20s to 50s. I have no idea if I will actually live longer, but I know I am having a lot more fun by “squaring the aging curve.” That’s one of the things I like best about this blog: lots of others who share my enthusiasm for moving.