Cats usually purr out of comfort and pleasure. This sound is produced by the contraction of the diaphragm muscles when cats inhale and exhale. Cats make these sounds when they feel relaxed, safe, and content, such as when they are being petted, resting quietly, or basking in the sun in a warm place.

However, if your cat purrs unusually frequently throughout the day or if her voice changes, this may be a sign that she has something discomfort or health problems. For example, cats may purr when they feel stressed, anxious, in pain, or otherwise unwell. In this case, you should closely observe the cat's other behaviors and physical conditions, and if you find any abnormalities, you should contact the veterinarian for examination in time.