The physiology behind intermittent fasting is real — but most of the brain benefits come from rodent studies, not human trials. A researcher’s honest look at what the evidence supports, what it doesn’t, and who should be cautious.
The Finnish sauna-dementia finding is real but observational — and while you’re actually hot, cognition tends to get worse. An honest look at what sauna use does for the brain, the likely long-term mechanism, and the safety cautions most articles skip.
The physiological sigh — double inhale, long exhale — is the fastest deliberate way to lower acute stress. The mechanism, what the randomised trials actually found, the three techniques worth using, and the practices to avoid.
“Biohacking” gets treated as one philosophy, but sauna, cold exposure, HRV tracking, and fasting each have wildly different evidence behind them. Here’s what each one actually shows — including an honest null result for HRV and cognition that rarely gets mentioned.
Cold water immersion at 14°C produces a 530% norepinephrine surge — the largest acute catecholamine stimulus documented for any non-pharmacological intervention — persisting for 3–4 hours. The complete neuroscience of cold exposure and cognitive performance: the norepinephrine and dopamine mechanisms, the autonomic adaptation that builds stress resilience, the 5-week cold shower protocol, and how cold exposure integrates with exercise and supplementation in the morning performance stack.
