Zone 2 and Polarized Training: A Way Out of the Grey Zone
Moderate 'grey zone' cardio done every day blunts both aerobic and high-end adaptation. What Zone 2 and high-intensity days each do, and a five-day 80/20 week that combines them.
Biohacking
Zone 2 Training: Why Going Slower Gets You Fitter
Zone 2 is the hardest pace at which lactate stays low and conversation is still possible. How it builds mitochondria and aerobic base, why elite athletes train mostly easy, and how to find your zone.
Cardio and Heart Risk: 150 Minutes a Week at the Right Intensity
About 150 minutes of moderate activity a week is linked to substantially lower cardiovascular mortality in large pooled cohorts. How to split that time between Zone 2 and intervals.
Heat Acclimation: What Heat Training Does for Endurance
Deliberately training your body to handle heat produces measurable physiological adaptations—some of which may boost performance even in cool conditions, though that claim deserves scrutiny.
Zone 2 Cardio and Longevity: Fact-Checking the Mitochondria Claim
Zone 2 — easy, conversational cardio — builds aerobic fitness, and fitness strongly predicts lower mortality. The claim that zone 2 is uniquely best for mitochondria is contested.
Breathwork for Stress: Cyclic Sighing and the Trial Evidence
Slow, exhale-focused breathing lowered stress and lifted mood in a 12-trial meta-analysis and a Stanford randomized trial. The evidence, the mechanism, a five-minute technique and where the risks are.
Sauna and Heat Exposure: The Cardiovascular Evidence
Regular sauna use is linked to lower cardiovascular and all-cause mortality in large Finnish cohort studies — an association, not proof. The evidence, the small trials, and how to use heat safely.
Cold Plunges and Cold Showers: Hype vs. Evidence
Cold water immersion is everywhere in biohacking. The evidence supports some benefits (recovery, maybe sleep) more than others (mood). Here is the honest read.
Intermittent Fasting: Modest Benefits Mostly from Eating Less
Intermittent fasting, especially time-restricted eating, produces modest weight and metabolic improvements in trials, mostly by helping people eat less. Who should be cautious.
Heart Rate Variability: Reading the Trend and Training by It
Heart rate variability promises a window into your recovery and readiness—but it's noisier, more personal, and easier to misread than the apps selling it would have you believe.
VO2 Max and Lifespan: Why Fitness Predicts Mortality So Well
Cardiorespiratory fitness is one of the strongest predictors of all-cause mortality, and unlike most biomarkers it is trainable at almost any age. What VO2 max means and how to raise it.
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