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Study finds hard physical labor raises risk for dementia
Work that can break down the body can also break down the mind.

- A new study out of Denmark finds that physical laborers are at an elevated risk of dementia.
- These findings hold even when other health factors are accounted for.
- The study also suggests that exercise can help reduce the risk of memory loss.
A new study out of Denmark confirms that the risk of dementia is higher for people employed as manual laborers than it is for those with less physically demanding jobs. It also somewhat confirms previous studies suggesting that light exercise reduces the likelihood of dementia. These seemingly contradictory findings, combined with other studies, continue to advance our understanding of how dementia works and, more importantly, how to prevent it.
All physical work and no play might really be bad for you
The study, "The effect of occupational physical activity on dementia: Results from the Copenhagen Male Study," was published in The Scandinavian Journal of Medicine & Science in Sports. It reflects 50 years of following nearly 5,000 Danish men, understanding their health and habits, and recording their medical histories.
In 1970, 4,271 Danish men working in various fields from railroading and road construction to banking and medicine filled out a questionnaire with two principal aims. The first portion focused on questions about their general health, including if they smoked, drank, suffered from obesity or high blood pressure, and if they regularly experienced high levels of stress. They then filled out a portion concerned with how much leisure exercise they tended to get and how physically demanding their job was.
Starting five years later, the researchers began to look into the test subjects' medical status in search of dementia cases using a combination of publicly available information and check-ins with participants.
The results were clear and concerning. Men who reported working physically demanding jobs developed dementia 55 percent more often than their peers working desk jobs. This number accounts for differences in education, socioeconomic levels, drinking habits, and other factors that could increase memory loss. It was also higher than for those whose jobs involved some physical activity but which were less strenuous.
While an association between strenuous physical labor and dementia had been assumed for years, this is the first major study to demonstrate the connection unambiguously. The researchers speculate that the mechanism at work may be related to the potentially negative impact of occupational physical activity on the cardiovascular system.
Study co-author Professor Andreas Holtermann noted that these findings present a challenge to health policymakers trying to improve brain health for several reasons:
"A lot of workplaces have already taken steps to improve the health of their staff. The problem is that it is the most well-educated and resourceful part of the population that uses these initiatives. Those with a shorter education often struggle with overweight, pain and poor physical fitness, even though they take more steps during the day and to a larger extent use their body as a tool. For workmen, it is not enough for example to avoid heavy lifts if they wish to remain in the profession until age 70. People with a shorter education doing manual labor also need to take preventive steps by strengthening the body's capacity via for example exercise and strength training."
As the professor implies, the findings of this study become more concerning when combined with the statistics showing that, at least among the Danes, men working in these physically intensive jobs are also more likely to smoke, drink, be overweight, remain unmarried, and find themselves in lower socioeconomic levels. All of these factors can contribute to memory loss.
The authors of the study suggest that these findings should be used to make advice on how to prevent memory loss more specific, as leisure-time physical activity (which is good for the brain) and intensive physical labor (which is bad for it) might not be easy to differentiate in current public health literature.
Additionally, they call for more studies into the relationship between occupational physical activity and dementia, with a particular focus on how people in differing socioeconomic levels are affected.
How to lower your risk of dementia no matter where you work
These results can seem frightening, but the study also points towards ways to reduce your risk of memory loss.
This study found mixed results regarding the benefits of exercise, but it points towards and does not contradict the large amount of evidence for its services in keeping the brain healthy. Exercise can help keep many parts of the brain working their best.
Other things that can help keep your brain healthy and memory loss in check include eating well, neither smoking nor drinking, and staying both mentally and socially active. As Carl Sagan mused, the brain is like a muscle, and it appears to work as any other muscle does. If used regularly and cared for as you care for any other muscle, it tends to remain healthy. If it is rarely used and treated poorly, it tends to decay.
Understanding how the brain works and how to keep it working are incredibly complex tasks. By confirming both that exercise is good for the brain and that potentially damaging labor is bad for it, this study can help medical professionals and public health experts create new guidelines for promoting brain health. We all stand to benefit from the results.
- Dementia may occur less often for people who read - Big Think ›
- A new approach to Alzheimer's based on physics and worms - Big ... ›
- Does forgetting a name or word mean that I have dementia? ›
Your body’s full of stuff you no longer need. Here's a list.
Evolution doesn't clean up after itself very well.
- An evolutionary biologist got people swapping ideas about our lingering vestigia.
- Basically, this is the stuff that served some evolutionary purpose at some point, but now is kind of, well, extra.
- Here are the six traits that inaugurated the fun.
The plica semilunaris
<img class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwMS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY3NDg5NTg1NX0.kdBYMvaEzvCiJjcLEPgnjII_KVtT9RMEwJFuXB68D8Q/img.png?width=980" id="59914" width="429" height="350" data-rm-shortcode-id="b11e4be64c5e1f58bf4417d8548bedc7" data-rm-shortcode-name="rebelmouse-image" />The human eye in alarming detail. Image source: Henry Gray / Wikimedia commons
<p>At the inner corner of our eyes, closest to the nasal ridge, is that little pink thing, which is probably what most of us call it, called the caruncula. Next to it is the plica semilunairs, and it's what's left of a third eyelid that used to — ready for this? — blink horizontally. It's supposed to have offered protection for our eyes, and some birds, reptiles, and fish have such a thing.</p>Palmaris longus
<img class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwNy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMzQ1NjUwMn0.dVor41tO_NeLkGY9Tx46SwqhSVaA8HZQmQAp532xLxA/img.jpg?width=980" id="879be" width="1920" height="2560" data-rm-shortcode-id="4089a32ea9fbb1a0281db14332583ccd" data-rm-shortcode-name="rebelmouse-image" />Palmaris longus muscle. Image source: Wikimedia commons
<p> We don't have much need these days, at least most of us, to navigate from tree branch to tree branch. Still, about 86 percent of us still have the wrist muscle that used to help us do it. To see if you have it, place the back of you hand on a flat surface and touch your thumb to your pinkie. If you have a muscle that becomes visible in your wrist, that's the palmaris longus. If you don't, consider yourself more evolved (just joking).</p>Darwin's tubercle
<img class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgxMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0ODUyNjA1MX0.8RuU-OSRf92wQpaPPJtvFreOVvicEwn39_jnbegiUOk/img.jpg?width=980" id="687a0" width="819" height="1072" data-rm-shortcode-id="ff5edf0a698e0681d11efde1d7872958" data-rm-shortcode-name="rebelmouse-image" />Darwin's tubercle. Image source: Wikimedia commons
<p> Yes, maybe the shell of you ear does feel like a dried apricot. Maybe not. But there's a ridge in that swirly structure that's a muscle which allowed us, at one point, to move our ears in the direction of interesting sounds. These days, we just turn our heads, but there it is.</p>Goosebumps
<img class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzEyNTc2Nn0.aVMa5fsKgiabW5vkr7BOvm2pmNKbLJF_50bwvd4aRo4/img.jpg?width=980" id="d8420" width="1440" height="960" data-rm-shortcode-id="8827e55511c8c3aed8c36d21b6541dbd" data-rm-shortcode-name="rebelmouse-image" />Goosebumps. Photo credit: Tyler Olson via Shutterstock
<p>It's not entirely clear what purpose made goosebumps worth retaining evolutionarily, but there are two circumstances in which they appear: fear and cold. For fear, they may have been a way of making body hair stand up so we'd appear larger to predators, much the way a cat's tail puffs up — numerous creatures exaggerate their size when threatened. In the cold, they may have trapped additional heat for warmth.</p>Tailbone
<img class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3MzQwMjc3N30.nBGAfc_O9sgyK_lOUo_MHzP1vK-9kJpohLlj9ax1P8s/img.jpg?width=980" id="9a2f6" width="1440" height="1440" data-rm-shortcode-id="4fe28368d2ed6a91a4c928d4254cc02a" data-rm-shortcode-name="rebelmouse-image" />Coccyx.
Image source: Decade3d-anatomy online via Shutterstock
<p>Way back, we had tails that probably helped us balance upright, and was useful moving through trees. We still have the stump of one when we're embryos, from 4–6 weeks, and then the body mostly dissolves it during Weeks 6–8. What's left is the coccyx.</p>The palmar grasp reflex
<img class="rm-lazyloadable-image rm-shortcode" type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMyMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjY0MDY5NX0.OSwReKLmNZkbAS12-AvRaxgCM7zyukjQUaG4vmhxTtM/img.jpg?width=980" id="8804c" width="1440" height="960" data-rm-shortcode-id="67542ee1c5a85807b0a7e63399e44575" data-rm-shortcode-name="rebelmouse-image" />Palmar reflex activated! Photo credit: Raul Luna on Flickr
<p> You've probably seen how non-human primate babies grab onto their parents' hands to be carried around. We used to do this, too. So still, if you touch your finger to a baby's palm, or if you touch the sole of their foot, the palmar grasp reflex will cause the hand or foot to try and close around your finger.</p>Other people's suggestions
<p>Amir's followers dove right in, offering both cool and questionable additions to her list. </p>Fangs?
<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Lower mouth plate behind your teeth. Some have protruding bone under the skin which is a throw back to large fangs. Almost like an upsidedown Sabre Tooth.</p>— neil crud (@neilcrud66) <a href="https://twitter.com/neilcrud66/status/1085606005000601600?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>Hiccups
<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Sure: <a href="https://t.co/DjMZB1XidG">https://t.co/DjMZB1XidG</a></p>— Stephen Roughley (@SteBobRoughley) <a href="https://twitter.com/SteBobRoughley/status/1085529239556968448?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>Hypnic jerk as you fall asleep
<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">What about when you “jump” just as you’re drifting off to sleep, I heard that was a reflex to prevent falling from heights.</p>— Bann face (@thebanns) <a href="https://twitter.com/thebanns/status/1085554171879788545?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script> <p> This thing, often called the "alpha jerk" as you drop into alpha sleep, is properly called the hypnic jerk,. It may actually be a carryover from our arboreal days. The <a href="https://www.livescience.com/39225-why-people-twitch-falling-asleep.html" target="_blank" data-vivaldi-spatnav-clickable="1">hypothesis</a> is that you suddenly jerk awake to avoid falling out of your tree.</p>Nails screeching on a blackboard response?
<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Everyone hate the sound of fingernails on a blackboard. It's _speculated_ that this is a vestigial wiring in our head, because the sound is similar to the shrill warning call of a chimp. <a href="https://t.co/ReyZBy6XNN">https://t.co/ReyZBy6XNN</a></p>— Pet Rock (@eclogiter) <a href="https://twitter.com/eclogiter/status/1085587006258888706?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>Ear hair
<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Ok what is Hair in the ears for? I think cuz as we get older it filters out the BS.</p>— Sarah21 (@mimix3) <a href="https://twitter.com/mimix3/status/1085684393593561088?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>Nervous laughter
<blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">You may be onto something. Tooth-bearing with the jaw clenched is generally recognized as a signal of submission or non-threatening in primates. Involuntary smiling or laughing in tense situations might have signaled that you weren’t a threat.</p>— Jager Tusk (@JagerTusk) <a href="https://twitter.com/JagerTusk/status/1085316201104912384?ref_src=twsrc%5Etfw">January 15, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>Um, yipes.
<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Sometimes it feels like my big toe should be on the side of my foot, was that ever a thing?</p>— B033? K@($ (@whimbrel17) <a href="https://twitter.com/whimbrel17/status/1085559016011563009?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>Godzilla vs. Kong: A morphologist chooses the real winner
Ultimately, this is a fight between a giant reptile and a giant primate.
The 2021 film “Godzilla vs. Kong" pits the two most iconic movie monsters of all time against each other. And fans are now picking sides.
How do you tell reality from a deepfake?
The more you see them, the better you get at spotting the signs.
Ancient cave artists were getting high on hypoxia
A new study says the reason cave paintings are in such remote caverns was the artists' search for transcendence.
