Chapter 1
The engine inside your cells
Chapter 2
Global secrets of slow and steady
Chapter 3
Building your own engine
Ch 1 · The engine inside your cells
coach Exercising at Zone 2 intensity triggers mitochondrial biogenesis, creating more cellular power plants that produce ATP for efficient energy.
Quiz
What is the main energy-carrying molecule that mitochondria produce to power our muscles?
Quiz
What are the tiny structures inside your cells that convert food into usable energy called?
coach Metabolic flexibility allows your cells to switch easily between burning fats and carbohydrates.
Quiz
At a Zone 2 intensity level, which fuel source does your body primarily rely on for energy?
Quiz
What is the term for your body's ability to switch efficiently between burning fats and carbohydrates?
Fun Fact
Mitochondria count: A single active muscle cell can contain over 2,000 mitochondria, showing just how much energy-producing machinery your body can pack into a tiny space.
Quiz
During Zone 2 exercise, blood lactate levels typically remain below which chemical threshold?
Quiz
What is the primary cause of the sudden muscle 'burn' and fatigue during high-intensity workouts?
Glossary
mitochondrion (noun)
An organelle found in most eukaryotic cells that generates adenosine triphosphate to power cellular processes. Physiologist Iñigo San-Millán discovered that low-intensity exercise directly stimulates the growth of these organelles.
An organelle found in most eukaryotic cells that generates adenosine triphosphate to power cellular processes. Physiologist Iñigo San-Millán discovered that low-intensity exercise directly stimulates the growth of these organelles.
Quiz
According to health research, moving from a low to a moderate VO2 max can reduce your risk of all-cause mortality by up to what percentage?