Zone 2 for Metabolic Health
The same training that builds Tour de France champions can help repair a struggling metabolism. Zone 2 improves how your body handles fat, sugar and insulin.
San Millan's research points to a problem he calls metabolic inflexibility: people with conditions like type 2 diabetes or metabolic syndrome lose the ability to burn fat well and produce more lactate at easy efforts, a sign their mitochondria are struggling. Zone 2 targets this head on. By rebuilding mitochondria and restoring fat-burning, it can improve blood sugar and insulin sensitivity over time. He describes Zone 2 as both a way to measure metabolic health and a way to treat it.
Why it worksâ–¼
Do easy cardio most days
Frequent, steady aerobic work is what steadily rebuilds mitochondria and fat-burning capacity.
Stay in the fat-burning zone
Going too hard shifts you to burning sugar and misses the metabolic benefit you are training for.
Pair it with fewer refined carbs
Exercise and diet work together. Reducing refined carbs helps your body relearn to burn fat.
Watch your progress over weeks
Metabolic change takes weeks to months. Simple markers show the training is working.
- People working on blood sugar, insulin resistance or metabolic syndrome
- Anyone who wants exercise that targets the root of metabolic health
- People who prefer gentle, sustainable cardio over punishing workouts
- Education based on San Millan's published work, not medical advice.
- If you have diabetes or take medication that lowers blood sugar, exercise can drop your glucose. Coordinate any new routine with your doctor.
- This supports medical care for metabolic conditions, it does not replace it.
- No products are sold here.
- July 3, 2026 Protocol published.
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Not medical advice. This page is for education only and is not a substitute for professional medical care. Consult a qualified clinician before changing your health routine.
Independent curation. YourProtocol.ai is an independent platform. This protocol is based on the publicly available work of Inigo San Millan and is not created, reviewed, endorsed by, or affiliated with Inigo San Millan or University of Colorado School of Medicine.