Louisa Nicola@louisanicola_
The fastest way to upgrade your fitness engine backed by science
Massive 2024 meta-analysis just dropped on muscle mitochondria and capillaries. Here is what 5973 participants revealed
1. All training works
Endurance, HIIT, and sprint intervals all increased mitochondrial content ~23 to 27 percent
2. Intensity wins on efficiency
Sprint intervals were ~2.3x more efficient than HIIT and ~3.9x more than endurance per hour
3. Frequency matters more than style
6 > 4 > 2 sessions per week = bigger gains in mitochondria and VO2max
4. Capillaries grow fast but early
Most capillary gains happen in the first 4 weeks, mainly in untrained people
5. Your starting point is everything
Lower fitness = bigger improvements across mitochondria, VO2max, and capillaries
6. Age, sex, and disease do not limit adaptation
Your body can adapt at any stage of life
7. VO2max improves similarly across methods
But HIIT trends higher, sprint intervals give the most return per time
Consistency and effort beat the type of workout. Start where you are and train hard. Your biology will respond
