Blog
Ideal humidity for home: where the 40–60% figure comes from and what it covers
Ideal humidity for home: the 40–60% range is a 1986 compromise between mites, mold and viruses, not a tested threshold. What dry air and dampness are linked to.
Can exercise make you sick? Where the exercise and immunity debate stands
Can exercise make you sick? A marathon survey, the open window theory and a debate paper by both camps: what exercise and immunity research agrees on, and what is still unresolved.
Cycle syncing workouts: what two reviews found about training by menstrual phase
Cycle syncing workouts, planning training around menstrual phases, are popular. What a 78-study meta-analysis and an umbrella review found, and why the authors reject general rules.
Seasonal diseases: why infections have a calendar and why it differs by country
Seasonal diseases are not only flu: a review of 60+ infections found eight drivers of seasonality. Examples from cholera to dengue, why one disease has different seasons in different places.
Excess winter deaths are higher in milder-winter countries: what the data show
Excess winter deaths in Europe are not highest where winters are coldest. What six studies found about cold homes, heating and mortality, and why none of them proves a cause.
What affects immunity: what research shows and what is marketing
What affects immunity, according to the studies: sleep, stress, social ties, age, vitamin C and echinacea, and why "boost your immunity" is the wrong frame. Evidence and limits for each.
Can you catch a cold from being cold? What a chill can and can't do
Can you catch a cold from being cold? A chill cannot create a virus, but some studies link falling temperature with more colds. What each study measured and what is still unknown.
Geomagnetic storms and wellbeing: what's real and what's myth
Do magnetic storms really affect how you feel? A skeptical, evidence-first look at the cardiovascular research, why the studies are so hard to trust, and why belief runs so far ahead of data.