Dexa scans are helping people ‘gamify’ their health and longevity

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I am lying on my back in a brightly lit room in a Toronto sports medicine clinic as a scanner slowly moves from the top of my head to the tips of my toes. Five minutes later, I will have more numbers about my body than I ever thought I wanted or needed.

I will know how much lean mass and fat mass I have, and exactly where it is located throughout my body, my resting metabolic rate, relative skeletal muscle index, bone mineral density, plus the ratio of fat around my waist to the fat around my hips – all of it and more laid out in charts and graphs in a seven-page report.

The DEXA scan – short for dual-energy X-ray absorptiometry – has become one of the most popular tests for people wanting to live healthier and longer lives. As wellness culture has become increasingly interested in longevity, the scan, which typically costs around $100, has become an accessible tool toward that goal, much more so than travelling to a far-flung Blue Zone, an area of the world where people seem to live exceptionally long lives, or delving in to biohacking, a broad term that covers a wide range of efforts to engineer the ideal body.

It’s the depth of metrics a DEXA provides that has helped make it so popular.

“Everybody should have a DEXA scan. You just have to know this data,” Toronto-born longevity doctor and bestselling author of Outlive: The Science and Art of Longevity Peter Attia said on his podcast last year. Interest was building before that and lately Dr. Amir Majidi’s phone has been ringing off the hook. His Toronto clinic, Push Pounds Sports Medicine, currently does 20 DEXA scans a day and there is a three-week waitlist.

“The scan stands as one of the most accurate ways that we can assess body composition,” says Majidi. But just how much you’ll benefit from getting one will probably depend on how specific you are about your goals and your pursuit of them. And though the scan can help track progress toward many fitness goals, it has its limits.

Now that I’m in my late 40s, the question of how well I’m aging – which was never really a question before – is on my mind. The scan, I thought, could provide at least some of the answers.

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For decades, the DEXA scan has been used to diagnose osteoporosis thanks to its ability to measure bone mineral density. But because it can also show exactly how much fat and lean tissue a person has and where it is, it eventually became popular with athletes looking for a competitive edge, Majidi says.

It’s especially popular among bodybuilders who want to achieve perfect muscle symmetry, and weekend warrior runners who want the exact same amount of muscle in their left leg as they have in their right.

“A lot of people are optimizing their performance for athletics,” says Peter Schwagly, founder of Bodycomp Imaging, a B.C. company that offers DEXA scans.

A lot of other people are simply optimizing for better overall health, especially as the dangers of visceral fat – diabetes, heart disease, some cancers and high blood pressure among them – have become more widely known.

“Someone goes in for a DEXA scan today and sees their body composition and says, ‘I’m carrying around a lot of visceral fat. My dad died of a heart attack. I’m going to develop a diet and fitness plan to correct this,’” Schwagly says.

The scans provide a snapshot of how well a person is eating and staying fit – fat and muscle mass can be influenced by lifestyle, after all – and the data provide the feedback to help people change their behaviour, Majidi says.

But if someone is concerned about their health and how they might have to change their lifestyle to live longer, a DEXA probably can’t tell you more than a tape measure could, says Stuart Phillips, a professor of kinesiology at Hamilton’s McMaster University.

If in adulthood you are only a couple of pant sizes bigger than you were in high school you’re probably fine, health-wise, but if you were a 30 then and wear a 42 now, “I don’t need a DEXA scan to tell you what you need to probably do,” Phillips says.

Which might be true, but a tape measure can only tell you so much. It is the granular details a DEXA scan reveals, and how those details can change through lifestyle adjustments, that prove to be motivating for so many people, says Dr. Darrin Germann, a sports sciences resident at Push Pounds.

“Having more access to a lot of this kind of data and technology for people, it gamifies health,” he says.

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Often, clients will get their scan and then eagerly come back in three months to see how changes to their diet and exercise have altered their body composition and improved their numbers, like a kid returning to an arcade psyched to beat his high score, Germann says.

Leigh Gabel, an assistant professor of kinesiology at the University of Calgary, says what the scan can show a person about how their body composition is changing over time makes it valuable from a longevity standpoint.

“If you get it done every year or every two years, you do get a sense for how muscle and fat mass and bone mass is changing,” she says.

We all typically add fat mass and lose muscle mass as we age. The DEXA scan can help tell what are normal age-related changes and what are not.

“Once you have a baseline value, then you can better understand whether changes are meaningful,” Gabel says.

Despite the heaps of data a DEXA provide, there is still much it can’t tell you.

For one, it says nothing about cardiovascular fitness. For that, Majidi recommends a VO2 max test, which measures how much oxygen your body absorbs during exercise.

And as Phillip points out, there is so much about healthy aging that isn’t covered by these sorts of metrics, particularly when it comes to the link between longevity and social connection.

“Do you have a good circle of friends? Did you talk to three other people today and ask them how they’re doing? Did you sit down with family members and have a meal?” he says.

Majidi, meanwhile, cautions against fixating on scan numbers.

“Using it as the Holy Grail of end all, be all – these are my DEXA numbers! – that’s when it goes a bit overboard,” he says.

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Looking at my scan, I begin to wonder how a season of more exercise and smarter eating might change the picture.

How could the amount of muscle in my arms and shoulders change after a summer of swimming? How could cutting down on pasta get my spot on the fat mass graph down to the lower regions for guys my age?

Do I care that my right leg has nearly one pound more of lean mass than my left, or that the right side of my trunk has 2.3 more pounds of lean mass than my left? Not really. Not at all, actually.

But looking over the report’s graphs and charts and colour-coded numbers, there’s a strong temptation to tinker and adjust and optimize.

Whatever my misgivings are about the overmetrification of health – and they are many – when Majidi invites me to return for another scan at the end of the summer to see what changes the season’s lifestyle has produced, I know that I’ll be back.