A common misconception of cat purring is that it is a reaction to feeling happy and content. On the contrary, cats can also purr when they feel anxious, tense, or when faced with a traumatic experience. Theories about why cats purr seem to be centered on the fact that the frequency of purrs tends to be between 25 and 150 Hertz. Sounds at this frequency have also been associated with various healing and growth properties which may account for purring during traumatic or stressful events.

However, a more recent theory suggests that purring promotes the release of endorphins which are sometimes known as “feel good hormones.” Endorphins are central to the healing process in humans as well as cats as they are a natural analgesic. As such, purring can be a self-soothing mechanism that helps cats to deal with stress. Interestingly, purring seems to have a healing effect on humans as well. There have been many documented cases of cats helping to lower the blood pressure of their owners, and there may be other health benefits as well. Consequently, many hospitals and retirement homes use cats to sooth patients.

Other than the happy purring of cats, purrs may be associated with different goals. First purring can be reassuring for kittens. A mother’s purr allows kittens to know she is close. Similarly, we’ve already discussed how purring can reduce feeling of anxiety or stress for the cat itself. Finally, purring with humans may be a sign of affection. By purring around humans, cats are letting their owners know that all is well. Likewise, a cat’s purr signifies to strangers that they shouldn’t be concerned. Interestingly, there have even been cases of cats purring to sooth their owners in times of stress. When a cat senses that you are tense or anxious it may begin purring to let you know that you can seek comfort in them.