How Different Kinds of Exercise Grow Muscle Powerhouses and Blood Supply
Effects of Exercise Training on Mitochondrial and Capillary Growth in Human Skeletal Muscle: A Systematic Review and Meta-Regression
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Endurance training increases capillary density more than sprinting—even though all types add similar numbers of capillaries per fiber.
Most assume harder workouts = better adaptations, but here, lower-intensity steady cardio wins in vascular density because intense training causes muscle fibers to grow, diluting the capillary concentration.
Practical Takeaways
Do sprint interval training (e.g., 4–6 x 30-second all-out efforts) 2–3 times per week to maximize mitochondrial gains in minimal time.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Endurance training increases capillary density more than sprinting—even though all types add similar numbers of capillaries per fiber.
Most assume harder workouts = better adaptations, but here, lower-intensity steady cardio wins in vascular density because intense training causes muscle fibers to grow, diluting the capillary concentration.
Practical Takeaways
Do sprint interval training (e.g., 4–6 x 30-second all-out efforts) 2–3 times per week to maximize mitochondrial gains in minimal time.
Publication
Journal
Sports Medicine (Auckland, N.z.)
Year
2024
Authors
Knut Sindre Mølmen, N. Almquist, Ø. Skattebo
Related Content
Claims (6)
Doing light, steady exercise—like a brisk walk—can boost the energy powerhouses in your muscles.
For people who aren't super fit to start with, different types of workouts—like steady cardio, intense interval training, and short sprints—boost the energy powerhouses in their muscles by about the same amount, around 23–27%.
If you're just starting to get fit, different types of workouts like steady jogging, intense intervals, and all-out sprints all help grow similar numbers of tiny blood vessels per muscle fiber. But jogging-style workouts boost blood vessel density more because they don’t make your muscles grow as much, so the vessels aren’t stretched thinner.
People who start out less fit tend to see bigger improvements in their stamina and muscle health when they begin exercising, no matter their age or gender — the lower your starting fitness, the more you gain.
Sprint workouts might boost your muscle energy factories way faster per minute than other types of exercise — about 2-4 times more efficiently than harder or longer workouts, especially if you're just starting out or somewhat active.