General health
⏰The 30-Second Test That Predicts Mortality
30% of 65-year-olds have a fall every year while 50% of 80-year olds do.
If you’ve seen it happen to someone of that age, you’ll know not just how dangerous it can be in the moment, but how it can also wreck people’s confidence.
And while you may be some way away from your 60s or 80s, the fact is, the kinds of problems with balance, leg strength and flexibility that increase your chances of falling begin decades earlier.
So, what if there were a 30-second test you could do right now that could help predict whether you’re at greater risk of a fall than someone else your age?
Well, humour me for a second.
If you’re sitting down while you’re reading this…stand up…and then sit down again.
However, if you’re standing up, just sit down for a second (if you can. If you’re on a busy train or bus, this might have to wait) and then stand up.
That’s the test.
Standing up and sitting down.
You just have to do it for 30 seconds, and the number of times you can do it can reveal so much about your overall strength and fitness, including:
- Predicting the number of falls in older men (mean age 91...91!), where the fewer repetitions they could do correlated with the number of falls they suffered over one year (PMID: 28464024).
- Predicting all-cause mortality in adults aged 51–80 (PMID: 23242910).
- Identifying which individuals are most likely to suffer complications when recovering from surgery (PMID: 33356620) and cancer treatment (PMID: 38957165).
I’ve been genuinely blown away by how powerful this simple test seems to be.
Most of the research into it has been done with older adults, and if you’re aged 60+ and can do more than 14 repetitions for men, or 12 for women, you’re doing well.
However, the 1-minute average (median) for 20–24-year-old males is 50, while it’s 47 for women of the same age (PMID: 23974352), so halve those values if you do it for 30 seconds.
Here are your "do-now" actionables:
1️⃣ Given how simple it is to do, it’s a no-brainer to me that you should try the sit-to-stand test for yourself.
2️⃣ By all means try to improve your score, but only compare your results with yourself, no one else.
3️⃣ If you spend large parts of the day sitting down, stand up and walk about for 1 or 2 minutes every half an hour.
4️⃣ Walking more and walking up stairs will build strength in your legs and improve cardiovascular fitness.
5️⃣ Single-leg strength is also important. Simply standing on one leg for 30 seconds is a good single-leg workout.
Gut health
🥵 The Bacteria Behind The Fever
If you’ve ever experienced a fever after receiving a vaccine, but wondered why someone else who received the same vaccine didn’t, a new study (PMID 42848888) might provide an answer.
Researchers tracked 171 adults after they received a COVID-19 vaccine.
Each day, participants had their temperature taken three times to monitor fever, and provided blood and stool samples to measure gut microbiome composition and immune markers.
Here are the findings:
- Receiving the vaccine had no significant effect on overall gut microbiome composition.
- However, individuals who experienced fever tended to have chronic low-grade intestinal inflammation and more bacteria associated with a particular type of flagellin.
Flagellins are the whip-like structures that some bacteria use to move around.
But they’re more than just microscopic motors.
Flagellin can also act as a molecular signal recognised by certain immune cells.
When the immune system detects flagellin, it can activate signalling pathways that trigger an inflammatory response.
To test the hypothesis that a flagellin-dominated gut microbiome is associated with heightened inflammation, the researchers transferred gut microbiome samples from fever-positive participants into human colonic organoids — essentially lab-grown models of the colon made from human cells.
The result? An increased inflammatory response.
Finally, when they added components associated with a typical Western diet, such as certain food additives, to these lab-grown models, they saw increased production of bacterial flagellin.
Now, this study cannot prove that changing your diet will reduce your likelihood of experiencing a fever after vaccination. However, it highlights two important points:
1️⃣ The gut and the immune system are tightly interconnected.
2️⃣ The gut microbiome can respond to changes in what we eat, sometimes within just a few days.
Which is why I’m so bullish on meeting, or even exceeding the recommended daily amount of 30g of dietary fiber.
And a simple way to get more fibre is to add one LOAM serving to your morning coffee, smoothie or overnight oats (it's formulated to be heat stable so you can even bake with it!).
REFLECTIONS
👌 It's OK To Look After No. 1
You know how on airplanes they always tell you, “In case of an emergency, life jackets can be found under your seat. Parents should put their own life jacket on before helping their children”?
I haven’t flown with my son yet, but that advice, which frankly I’ve always ignored up till now because, why wouldn’t I? suddenly seems a bit hard to swallow.
However, the more I think about it, the more it makes sense.
It’s literally true that in a life-or-death situation, you can’t help anyone if you’re injured, dying or dead.
But to be a little less dramatic, I can’t be a good father or husband, let alone a great one, if I’m not looking after myself.
- We all know we’re a different person after a good night’s sleep compared to a lousy night.
- And what about how you feel after you eat a healthy lunch, maybe even taking a walk afterwards, compared to when you have a burger and chips with a couple of beers and later can barely stagger to the sofa?
- Which version of you do your kids/partner prefer: the one who’s stressed out because of deadlines, or the one who doesn’t even mention work when they’re home?
Just doing the boring basics of sleep, nutrition and exercise has the biggest effect on how good a father or husband I can be. It’s 100% in my family’s interest that I nail those 3 things whenever I can.
Of course, sometimes life just gets in the way, and it’s no one’s fault that you’re not the best version of yourself for a day or two. So what? No one will remember those odd occasions if you consistently show up for your loved ones the rest of the time.
You might even call looking after yourself an act of loving kindness towards the ones who are most important to you.
👋 Who are you again? I’m Karan Rajan - a doctor and curious explorer of all things health and wellness. I'm the founder of LOAM Science, a microbiome company aiming to create the best fiber product in the world! I host the Dr Karan Explores Podcast, where I talk to experts in science and medicine to cut through the BS of modern health advice. If you'd like an easy way to dig through the archive, you can ask me any questions about the podcast and talk to my digital librarian here. I've also written two books "This Book May Save Your Life" and "This Is Vital Information".
If you feel strongly about some health things or just want to say hi? Hit reply... I’d love to hear it and hear from you! (yes I read every reply!!!)f
