A cat’s purr is not just background noise in a quiet room. The sound emerges as a low, repetitive vibration that clusters in a specific band of acoustic energy. Measurements show that many domestic cats produce fundamental frequencies between roughly 25 and 150 Hz, a range that overlaps with known therapeutic vibration used in clinical and sports settings.
At these frequencies, mechanical loading can trigger osteogenesis, the process by which bone tissue forms and remodels, and can influence collagen synthesis in soft tissues. Researchers studying mechanotransduction describe how cells convert physical vibration into biochemical signals, modulating bone density and tissue repair rates. In that context, the purr begins to resemble a built‑in, low‑power physiotherapy device, generated by laryngeal muscles and the diaphragm with minimal extra energy cost to the animal’s basal metabolic rate.
The pattern is striking because cats purr not only during relaxed social contact but also when injured, stressed, or immobilized. Instead of a simple emotional broadcast, the behavior can be read as a quiet maintenance routine that runs whenever movement is restricted. The same sound that reaches a human hand as a faint buzz may be saturating the cat’s own skeleton and connective tissues with clinically relevant vibration.
