Blog
Why we get sick more in winter: cold, dry air, and indoor time
What research says about why respiratory infections rise in the cold season: dry air, a cooler nose, crowded indoor days, and which findings come only from animals and cells.
Immunity: what research links to it, and what is marketing
Why "boost your immunity" is the wrong frame, and what studies measured: sleep, stress, social ties, age, vitamin C and echinacea. Evidence type and limits for each.
Sleep and catching a cold: what the virus-challenge studies show
Healthy volunteers were given a cold virus on purpose; those who had slept less beforehand fell ill more often. What the studies measured, how uncertain the numbers are, what they did not test.
Fatigue and getting sick: cause, or the first symptom?
Does being worn out make a cold more likely, or is the tiredness already the infection starting? What virus-challenge studies and wearable data show, and why looking back rarely settles it.
Does getting cold give you a cold? What a chill can and can't do
A chill cannot create a virus, but some studies link a drop in temperature with more colds. What each study measured, how reliable it is, and what nobody knows yet.