A 1,600-year-old text defined yoga as stopping your mind's fluctuations
The Yoga Sutras open by defining yoga not as a physical exercise but as the stilling of the mind's constant fluctuations between thoughts. Patanjali lays out an eight-limbed path toward that stillness, moving from ethical restraints and physical postures through breath control and meditation to a final absorbed state called samadhi. The physical yoga practiced in modern gyms borrows its name, and some of its vocabulary, from this much older philosophical framework.