Amidst all the chaos and destruction in the world, science is still happening (although the funding situation is also chaotic and destructive, but never mind that for the moment). Interesting questions are being asked, tested, and interesting answers are being given. Here are some of them (mostly courtesy of Sam, who sends these to me– thanks, Sam!)

Question: Does exercise result in a net calorie reduction, or does the body compensate to balance things out?

Answer: we don’t know yet. But, a bunch of scientists are hard at work testing different active subpopulations (from Tanzanian Hadza hunter-gatherers to American collegiate cross country runners) to look for ways that human metabolism responds to energy output. This article from Outside magazine gives a detailed and accessible overview of recent research on the topic.

Good news: even if exercise doesn’t result in a ton of extra calories burned (if that’s your goal), it still results in other good things, like increased longevity, better sleep and overall well-being.

Question: Does cycling make you smarter?

Answer: Maybe, in some ways, for a little bit. Here’s what this article in The Cycling Week magazine had to say about it:

A study published in the Journal of Clinical and Diagnostic Research found that people scored significantly higher on memory, reasoning, and planning tests after just 30 minutes of spinning on a stationary bike.

This effect is primarily linked to the production of a protein called BDNF (Brain-Derived Neurotrophic Factor). BDNF acts like a fertilizer for your brain, helping to grow new cells and protecting existing ones from decay.

Essentially, every mile you ride is an investment in your brain’s structural integrity and future processing speed.

Yay! Does cycling do anything else good to your brain? The article also cites research results suggesting that cycling promotes lower dementia risk, increased neurogenesis (creation of neurons in the hippocampus) and psychological resilience (this last one is less surprising if you’ve tackled big hills at very low speed, as I have).

Question: Can exercise help reduce my cancer risk?

Answer: yes, a bit. But the research study supporting this is small and very preliminary. Here’s the deal, from an article in Men’s Health magazine:

The researchers looked at 30 men and women between the ages of 50 and 78. All met the criteria for having extra weight or obesity. Each person underwent a short but intense cycling test that lasted about 10 minutes.

Afterward, the researchers collected blood samples from everyone and analyzed them for 249 proteins. Thirteen of the 249 proteins increased after exercise. This included interleukin-6, which helps to repair damaged DNA. Exercise raised the levels of other molecules in the blood that work to reduce inflammation, support blood vessel health, and improve metabolism.

According to the researchers, the evidence showed that 10 minutes of exercise was enough to support DNA repair to lower colon cancer risk. Though keep in mind, these were short but intense bursts of exercise. A slow, leisurely stroll wouldn’t qualify.

There are a bunch of things we don’t know, like what is the amount of reduced risk, and what is the variation in different subpopulations. Plus a bunch of other relevant factors that may influence the effects. Still, it’s good news.

Happy week, everyone, and enjoy some movement!

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.