Articles by Jaeyoung Ko, M.D.
-
How to Raise Your VO2 Max — Training That Works at Any Age
Norwegian 4x4 intervals raised VO2 max 7.2% in eight weeks, and sedentary 50-somethings gained 18% in two years. What the training evidence actually says.
-
VO2 Max Predicts Lifespan Better Than Smoking Does
Cardiorespiratory fitness outranks smoking as a mortality risk factor, a 122,000-person cohort found — the strongest lifespan predictor among five studies.
-
Two Official Protein Numbers. Which One Applies to You?
The 2026 guidelines say 1.2–1.6 g/kg. The RDA still says 0.8, unchanged since 2005. A physician on why both numbers exist, and which one is yours.
-
Sleep Is the Aging Lever You Can Actually Measure
More than a third of U.S. adults sleep under 7 hours. A physician on how sleep sets the pace of aging — and why regularity may matter more than hours.
-
Your Multivitamin Has Zinc. So Does Your Zinc.
Upper limits count everything you take in a day, not one product. Your multivitamin, zinc, and fortified cereal overlap. A physician shows the arithmetic.
-
You Lost 8 kg on Wegovy or Zepbound. How Much of It Was Muscle?
In trials, about 75% of weight lost on GLP-1 drugs was fat — similar to placebo. Where the "40% is muscle" figure came from, and what protects muscle.
-
How "Moderate Drinking Is Good for You" Quietly Disappeared
For twenty years the J-curve was settled wisdom. Genetic studies undid it. A physician on how the evidence flipped, and the four ways alcohol speeds aging.
-
Why the Gut Is Called the Second Brain — The Science of Gut Health
Your gut holds ~500 million nerve cells and ~100 trillion microbes. A physician on the gut-brain axis, the microbiome, and what actually helps.
-
Does Intermittent Fasting Actually Work? What to Know Before You Start
When you eat may matter as much as what you eat. A physician on the fasting research, the autophagy story, common schedules, and who should not.
-
Aging Has a Speed — and 4 Daily Habits That Set the Pace
Two people the same age can age at different rates. A physician-founder on four habits linked to slower biological aging — and why tracking beats willpower.