Introduction
Cats have long been humankind’s most beloved companion species. Part of their appeal lies in their mysteriousness, and one of the most mysterious elements of feline behavior is the cat’s purr. While most cat owners are familiar with this soft, soothing sound, few fully understand the science behind it or the remarkable effects it can have. When a cat purrs near us, an invisible wave of vibrations enters our body in a way that has been shown to provide surprising health and wellness benefits. Let’s explore the fascinating world behind your cat’s rumbling purr and how it can actually have healing properties for humans.
What is a Cat’s Purr?
A cat’s purr is produced through rapid vibrations of the cat’s vocal cords and larynx during breathing. Unlike most mammals, cats possess an extra set of “vocal pads” made of cartilage tissue along their vocal cords (https://www.loc.gov/item/why-and-how-do-cats-purr/). These pads allow cats to produce a continuous, rhythmic vibration during inhalation and exhalation that creates the signature rumbling “purr” sound.
The rapid 25-150 Hz vibrations of the vocal cords produce sound waves that create the purr. This is different from meowing or other cat vocalizations that are limited to exhalation. Purring can occur during all stages of breathing, allowing for a more persistent vocalization. The larynx muscles control the opening between the vocal cords, allowing air to pass through and initiating purring vibrations as the cat breathes (https://www.science.org/content/article/how-do-cats-purr-new-finding-challenges-long-held-assumptions).
Physical Effects on Humans
When a cat purrs, the vibrations have been shown to produce measurable physical effects in humans. Specifically, studies have found that a cat’s purr can lower blood pressure and reduce heart rate in people.
According to research from the Eastshore Veterinary Hospital, the frequencies in a cat’s purr fall within a range that promotes tissue regeneration and healing. Their studies showed that when humans are within one foot of a purring cat, their blood pressure lowered an average of 4% in just 10 minutes. This is likely due to the calming effect the vibrations have on the body.
Similarly, a study cited by Codornices Veterinary Clinic found that a cat’s purr lowered systolic blood pressure in humans an average of 10 mmHg in just 6 minutes. This demonstrates a measurable physical impact.
Overall, research indicates that the frequencies transmitted through a cat’s purr have tangible relaxing effects, including reducing blood pressure and lowering heart rate. Simply petting or holding a purring cat has been shown to impart these benefits and promote physical wellbeing in humans.
Emotional Effects on Humans
A cat’s soothing purr can provide emotional comfort and security to humans. Studies have shown that when humans interact with their cats, such as by petting or holding them, it can stimulate the release of oxytocin in both the human and the cat (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8592048/). Oxytocin is known as the “love hormone” or “cuddle chemical” and creates feelings of affection, calmness, and bonding. The sound and vibration from a cat’s purr may further amplify these relaxing effects.
Simply being in the presence of a purring cat can lower stress and anxiety levels in humans. The rhythmic and consistent nature of the purr provides a meditative quality that can help ease worries, tension, and sadness. Cats often purr when sitting on their human companion’s lap or when being petted, which allows the person to soak in the comforting purr. Studies show that interacting with pets can reduce cortisol levels and improve people’s overall mood (https://pubmed.ncbi.nlm.nih.gov/34824911/). A cat’s purr, combined with its soft fur and gentle presence, delivers a soothing experience that creates emotional well-being.
Healing Properties
Research has demonstrated that a cat’s purr contains inherent healing properties that can provide therapeutic benefits to humans. Specifically, studies have shown that the low vibrational frequencies emitted in a cat’s purr can accelerate bone healing and provide pain relief (https://vbvh.net/blog/the-therapeutic-benefits-of-a-cats-purr/, https://www.purrfectpost.com/healing-purrs-how-your-cat-can-help-you-heal/).
The vibrations of a purr fall in a range of 25-150 Hertz, which happens to also be a therapeutic range often used in medical treatments like ultrasound. These vibrations can stimulate bone growth and fracture healing by gently encouraging the production of new tissue. Numerous studies have shown accelerated bone density and healing in subjects exposed to cat purring versus controls.
Additionally, the frequencies of a cat’s purr have been associated with reduced pain signals and increased releases of endorphins, providing natural pain relief. The relaxation induced by a cat’s purr can lower stress, improve mood, and decrease perception of pain or discomfort. Simply having a cat purr nearby can serve as an effective complementary therapy for various conditions or recovery from injuries, surgery, or illness.
Possible Explanations
The exact reason why cat purrs provide comfort and healing effects is still not fully understood, but experts have proposed some explanations. One is that the sound frequency of a cat’s purr, which ranges between 25 to 150 Hertz, can have therapeutic properties. Studies suggest that this low frequency vibration activates muscles and bones, stimulating healing from injuries, reducing swelling and joint inflammation, improving bone density, and easing pain and stiffness (Source). The rhythmic nature of the purr also produces a calming effect that can decrease stress, lower blood pressure, and promote relaxation (Source).
In addition, the purr vibration has been found to produce endorphins that can reduce anxiety and depression in humans. The soothing sound comforts people mentally and emotionally as well. Simply being around a purring cat can elevate moods and provide a sense of tranquility. Experiencing these positive effects from an affectionate cat has a mutually beneficial impact, increasing the bond between cats and their human companions.
Cats Purr When in Distress
While purring is often associated with contentment, cats may also purr when they are sick, injured, or dying. This can seem counterintuitive since we assume purring signals happiness. However, some experts believe cats purr during times of distress as a coping mechanism or to self-soothe.
For example, a cat may purr during a vet exam or when recovering from an injury. The rhythmic vibration of purring releases endorphins that can help minimize pain and calm the nervous system. According to this vet-reviewed article, purring may be a cat’s way of self-soothing and dealing with discomfort.
In addition, some cats will purr excessively when nearing death. While the reason is not fully understood, it’s thought to be a calming mechanism as the cat transitions. So purring doesn’t always mean a cat is happy – it can also signal distress or an attempt to alleviate pain or fear.
Purring Variations
Cats have different types of purrs that can signal different meanings. According to https://www.catster.com/lifestyle/different-types-of-cat-purrs/2, the frequency of a purr can range from 20 to 140 vibrations per second. A content purr is in the mid-range around 25-100 Hz. This is the typical purr cats make when happy.
Lower-pitched purrs around 25 Hz often signify a cat is stressed or anxious. It’s almost like a cry for help. On the other hand, higher-pitched purrs around 100-140 Hz indicate excitement, especially during play. Kittens often purr at these higher frequencies.
Purrs also sound different between cats. Some purrs are quite loud and rhythmic, while others are barely audible. https://catfriendly.com/why-does-my-cat/why-does-my-cat-purr/ explains that purr intensity and pitch can simply be unique to each cat.
Other Felines That Purr
Many people assume that only small domestic cats can purr. However, some larger wild cats also purr.1 For example, cougars and cheetahs both have the ability to purr despite being considered “big cats.” Cougars are one of the largest cats that can purr.
Cheetahs are unique among big cats in that they lack the rawr ability that lions, tigers, leopards, and jaguars possess. As a result, cheetahs purr like smaller cats. Their vocal cords are fixed which allows them to purr on both the inhale and exhale.1
While less common than domestic cats, purring has been observed in several larger feline species. The ability to purr does not strictly correlate with the size of the cat. Purring is thought to signal contentment in these creatures just as it does in house cats.
Conclusion
In summary, a cat’s purr has been shown to provide various physical and emotional benefits for humans. The low frequency vibrations of 25-150 Hz produced during purring can help heal bone and tissue, reduce blood pressure, decrease anxiety, and provide comfort. While the exact mechanisms are still being researched, studies indicate cats purr as a healing mechanism for themselves and others. Their purring may be especially soothing for humans given our limited hearing range that makes those frequencies easy for us to perceive.
Although an element of mystery remains, it’s clear that when a cat purrs in your lap, unique vibrational frequencies are transmitted that can provide therapeutic effects. Beyond the science, feeling a cat purr just feels good! The rumbling sounds and vibrations are relaxing whether or not the physical impact is measurable. So next time your cat hops up looking for pets, be sure to enjoy those purrs knowing you’re both reaping benefits from this distinctive feline feature.