Is it dangerous to hold in a sneeze? What the case reports show
Stifling a sneeze is usually harmless, but doctors have documented rare, serious injuries — a torn throat and a fractured voice box — when the trapped pressure has nowhere to escape.
The runner's high probably isn't an endorphin rush, studies suggest
The endorphin story is a long-standing guess. When researchers blocked opioid signalling in 63 runners, the euphoria and calm still arrived — pointing to the body's own cannabis-like molecules instead.
Does cracking your knuckles cause arthritis? What the evidence says
Studies going back decades find no link between habitual knuckle cracking and hand arthritis. One doctor cracked a single hand for a lifetime to prove it — and got arthritis in neither.
Why microplastics studies are hard to trust: the methods problem
When researchers screened 101 human studies against basic quality criteria, none met all of them. The field's core difficulty is telling real particles from contamination.
Screen use explained at most 0.4% of the variation in adolescent well-being
Two large re-analyses of the same public datasets found the association is real, negative and very small. A third review found the association is not even consistent between the Global North and South.
In 43% of energy-availability studies, menstrual status is reported too vaguely to grade
The same audit found high-performance female athletes well represented in the field — and that the studies generating prevalence figures lean on self-reported food records and MET lookup tables.
In 7182 Soweto women, the standard sleep questionnaire did not hold together as one score
The Pittsburgh Sleep Quality Index global score is the field's default outcome. Tested in a large South African cohort, its single-factor structure fit poorly and internal consistency was modest.
Placebo responses in US pain trials grew for two decades. Drug responses did not.
Analgesic trials keep failing, and one reason is that the comparison arm keeps improving. Where a trial recruits, how long it runs and how big it is all move the placebo response — and none of that is about the drug.
95% of human-microbiome-into-mice studies reported the disease transferred too
A systematic review in Cell called that rate implausible and said it overstates the gut microbiome's role in human disease. A separate audit found the statistical tools themselves disagree.
Testosterone does look lower in each generation. The assays make it hard to be sure.
Two datasets report an age-independent fall in men's testosterone across birth cohorts. A separate study of nine thousand men found much of the variation between cohorts came from the tests themselves.
The sperm count decline is real in one dataset and unproven in another
A 223-study meta-regression reports sperm concentration falling 51.6% since 1973. Two published critiques argue the method cannot support that reading. Both sides are peer-reviewed.
Seven of 25 sports science studies replicated on all three criteria
The first large replication project in the field found effect sizes shrank substantially on repeat, and reports that many original authors declined to engage with the attempt.