Musculoskeletal damage from continuous vibration
Every hour on a two-wheeler transmits road vibration directly through the spine. A 2019 study published in the International Journal of Industrial Ergonomics found that professional two-wheeler riders exposed to whole-body vibration for more than four hours daily showed significantly higher rates of lumbar disc degeneration than non-riding workers. Indian delivery riders routinely exceed that threshold on roads that mix potholes, speed breakers, and broken asphalt. The lower back absorbs most of it. Riders rarely connect the chronic ache to the job until the disc has already compressed.
