u/DrJ_Lume

A new study found that Staphylococcus aureus invasion of human lung cells changed depending on the cells’ circadian phase.

When researchers disrupted the cellular clock by reducing BMAL1, a core circadian clock protein, bacterial invasion increased and the normal rhythm of susceptibility was blunted.

The effect was surprisingly large: bacterial uptake varied roughly 2–3x depending on circadian timing.

The study didn't test morning light directly, so we can't say morning sunlight prevents infection. But morning light is one of the strongest signals for keeping the human circadian system synchronized.

Another reason to think about circadian health as more than just sleep....

A new study found that Staphylococcus aureus invasion of human lung cells changed depending on the cells’ circadian phase.

When researchers disrupted the cellular clock by reducing BMAL1, a core circadian clock protein, bacterial invasion increased and the normal rhythm of susceptibility was blunted.

The effect was surprisingly large: bacterial uptake varied roughly 2–3x depending on circadian timing.

The study didn't test morning light directly, so we can't say morning sunlight prevents infection. But morning light is one of the strongest signals for keeping the human circadian system synchronized.

Another reason to think about circadian health as more than just sleep....(I also petition the mods to change the flair so that Circadian rhythm is separate from sleep; it is so much more than sleep!)

A new study gave 554 people three rounds of personalized debate about COVID-related conspiracy beliefs.

When participants knew they were talking to AI, belief confidence fell by about 7 percentage points.

When the same type of AI-generated conversation was presented as coming from a human, confidence fell by about 14 points.

The researchers expected AI to seem more neutral. Instead, participants saw it as less neutral and more threatening to their autonomy.

Interesting reminder that persuasion isn't just about the information.

Who we think is speaking matters too.

A study published this week analyzed 6,851 sleep studies collected over 21 years and found that sleep apnea severity varies seasonally.

That’s interesting because we often measure physiology once and treat that number as a fixed property of the person.

But blood pressure varies. Hormones vary. Sleep varies. Glucose varies.

A single measurement can be valid and still miss the bigger pattern.

We’re good at measuring biological states. We may need to get better at measuring biological patterns.

Have any of you noticed a seasonal pattern to your OSA?

A hard workout can sometimes make you less hungry, even though you have just burned more energy.

A recent trial found that high-intensity interval training increased GDF15 (growth differentiation factor 15) and FGF21 (fibroblast growth factor 21), two signals involved in appetite and energy metabolism. Participants also ate less at the following meal.

This suggests that post-workout appetite is influenced by more than willpower or calories burned. Intense exercise can temporarily change the hormonal signals involved in hunger.

The effect is likely acute and may vary based on fitness level, metabolic health, and exercise intensity.

Do intense workouts suppress your appetite, or make you hungrier later?

Researchers fed 15 healthy women identical meals across two cycle phases and watched the CGM. Breakfast and lunch responses didn't differ. But 30 min after dinner, glucose ran significantly higher in the luteal phase (post-ovulation, before your period)- the same stretch where progesterone and core body temp are up.

Your curve moves purely from where you are in your cycle. Worth logging the phase next to your readings before you write off a food.

I intermittent fast, eat pretty clean, and run a CGM occasionally. What kept bugging me: the meal I ate to break my fast would spike way harder than expected. Since I do everything "right," it made me a little uneasy that something was off.

Finally, I found a crossover RCT from this month. Healthy adults did a 48h fast, then had their glucose response to the first real meal measured on a CGM. After the fast, glucose tolerance was worse -a bigger refeeding spike, still elevated 24h later.

The authors frame this "fasting glucose intolerance" as a normal, temporary switch, which likely has a different mechanism from the chronic insulin resistance in diabetes, not the same red flag. The fast just rigs the test.

Sharing just in case any other fasters out there found similar results and were freaked out. Turns out it's normal, don't stress!

https://doi.org/10.1113/JP291000

A cohort of ~2,900 people

"Meal Timing Jetlag" the gap between your eating schedule on work days vs free days (weekends for most people). More of that mismatch was independently linked to higher anxiety, more depressive symptoms, and worse insomnia. The kicker: this held up even after adjusting for sleep-based circadian misalignment.

Big caveat: cross-sectional, so no causation (anxious people might just eat more erratically) or there may be a third variable causing both the mood symptoms and the erratic timing

But it's making me think more about my "first meal / last meal time".

https://www.sciencedirect.com/science/article/abs/pii/S0165032726010827?via%3Dihub

A while back, I posted that I wore blue-light blockers every night for a week and got exactly zero change in sleep or cortisol.

Found a crossover RCT (20 healthy adults, glasses worn 6pm→bed for a week, then switched to clear lenses), which corroborated my finding. Subjectively, people felt like they fell asleep a couple minutes faster and woke up less. But objective sleep time and quality didn't budge. And total sleep time was actually slightly shorter with the blockers.

Interesting study: older adults at increased Alzheimer’s risk, with low omega-3 intake.

They took 2 g/day omega-3 or placebo for 24 months.

The omega-3 reached the brain, increasing DHA in cerebrospinal fluid. But it didn’t improve cognition or brain volume.

Has anyone seen any convincing evidence for the use of Omega fatty acids?

Interesting study: older adults at increased Alzheimer’s risk, with low omega-3 intake.

They took 2 g/day omega-3 or placebo for 24 months.

The omega-3 reached the brain, increasing DHA in cerebrospinal fluid. But it didn’t improve cognition or brain volume.

Do you supplement omega-3 fatty acids? Why?

Have you seen the EWG sunscreen guide?

TL;DR of the guide: EWG reviewed thousands of SPF products and concluded that only a minority meet its standards for ingredient safety and balanced UVA/UVB protection. It tends to favor mineral sunscreens, and raises concerns about some chemicals which are detectably absorbed.

It PMO...

A sunscreen ingredient being “detectable” in blood does not automatically mean it is harmful. Whether that matters depends on dose, metabolism, and whether there is evidence of harm.

Meanwhile, the risks of UV exposure are not hypothetical. UV radiation is strongly linked to sunburn, premature skin aging, hyperpigmentation, DNA damage, melanoma, and non-melanoma skin cancers.

What worries me is that fear-based sunscreen content can push people away from regulated products and toward DIY “natural” alternatives which may sound cleaner or safer, but they do not provide reliable UV protection.

Rant over. What are your opinions and how do biohackers protect their skin from the sun?

I believe the standard protein recommendations are probably below what’s optimal, especially for people who are training, trying to build/maintain muscle, improve body composition, or support longevity.

For those of you tracking it: How much protein are you targeting per kg of body weight per day?

A major review concludes that nicotine vaping likely causes lung and oral cancer.

Researchers combined evidence from human biomarkers, animal studies, and lab experiments and found remarkably consistent signs of DNA damage, inflammation, and cancer-related cellular changes. They also identified carcinogens in e-cigarette aerosols, including volatile organic compounds and metals from heating coils.

We shouldn't repeat the mistake made with cigarettes and wait for long-term epidemiological data before taking action.

TL;DR: Vaping may not be the harmless alternative many assumed. The evidence suggests it likely increases the risk of lung and oral cancer.

It's hotly debated whether you should exercise in the morning or the evening.

I found a randomized trial suggests the answer is: whichever matches your chronotype.

Early birds who trained in the morning and night owls who trained in the evening saw greater improvements in blood pressure, HRV, fitness, glucose, LDL, sleep quality, and exercise adherence than people exercising at their non-preferred time.

Exercise is beneficial regardless of timing, but this study suggests that your circadian biology may determine how much benefit you get from the same workout.

The study determined choronotpe with the MEQ (you can take the survey here) and validated the findings with core body temp monitoring.

If healthcare systems pay for the costs of chronic disease, shouldn't they also reward people who actively reduce those costs?

Exercise, sleep optimization, nutrition, and other practices of the biohackers here save healthcare systems money over the long term. Yet the people investing time and money into those behaviors receive no economic benefit.

We subsidize activities that create public value: solar panels, EVs, vaccinations, etc. Why not biohacking?

In other words, is biohacking a personal hobby or an economic asset with lots of positive externalities?