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A Cat’s Purr

We’ve always intuitively felt that a cat somehow knows when we’re not feeling well and even where it hurts. Got a headache and a cat just seems to wrap around your head. A stomachache and a cat can’t seem to get off your abdomen. And purrs and purrs and purrs!

It was always believed that a cat’s purr was relaxing or stress reducing and that that led to any number of healthful benefits. While that may be so, science has shown that the cat’s purr is much more than just relaxing. Remember that it’s not just the sound of purring that’s important but more the tremor or vibration it produces.

A Cat’s Nine Lives

Interestingly, science has known for many years that vibrations at specific levels or frequencies cause healing changes in the body. They can, for example, induce bone growth and regeneration. Bone fractures heal faster and weakened bones begin to strengthen and rebuild.

Also, in the higher frequency ranges, the production of the body’s own natural anti-inflammatory compounds increases thereby reducing joint pain and swelling. There is further evidence of muscle, tendon and ligament repair within these frequency ranges as well, which has led to some popularity in sports medicine and gyms around the world, especially in the former Soviet Union where so much of this research was conducted.

It was also known through various veterinary studies, such as the one reported in The Journal of the American Veterinary Medicine Association for example (J Am Vet Med Assoc 99; 214(9): 1336-41), that cats rarely suffer bone or joint related diseases, including hip dysplasia, arthritis and ligament problems. Even bone cancers, such as myeloma or osteosarcoma, are almost unheard of in cats.

But it took researcher Elizabeth von Muggenthaler of the Fauna Communications Research Institute in North Carolina (FCRI), a specialist in the field of bioacoustics, to put it all together. Bioacoustics is the study of the frequency, pitch, loudness, and duration of animal sounds as it relates to the animal's behavior. Based on her research, she proposes that nature has endowed all kinds of felines with an evolutionary healing advantage in the simple act of purring.

Remember that purring takes energy and cats purr not only when all is well, but also when the cat is giving birth, hurt or just scared. There has to be a very good reason for the energy expenditure to produce purring, especially when the cat is physically stressed or ill. It would have to be somehow involved in its survival, and Muggenthaler set out to find how.

The Science Behind the Purr

She recorded and then measured the purr of forty-four felids (members of the cat family) including cheetahs, ocelots, pumas, domestic cats, and servals. Cats, from your house pet to lions and tigers in the wild, generally purr in the range of 20 to 140 Hertz (Hz). Some are as high as 150 Hz but the average housecat comes in at about 25 and 50 Hz.

Research has already shown that exposure to frequencies at that same 20 and 50 Hz level induces increased bone density. In one study, for example, chickens were placed daily on a vibrating plate for 20 minutes, which resulted in stronger bone growth (National Geographic January, 2001 p. 11). Further, in 1994, Dr. Chen and his associates, working with rabbits, determined that frequencies of 25 and 50 Hz promoted bone strength by 20%, stimulating both the mechanism and speed of fracture healing (Chen et al, “The Effects of Frequency of Mechanical Vibration on Experimental Fracture Healing”. Chinese Journal of Surgery, 32 (4), 217-219, 1994).

There’s even a popular saying amongst veterinarians, “If you put a cat and a bunch of broken bones in the same room, the bones will heal.”

There is also substantial documentation that low frequency vibration induces pain relief and healing of tendons and muscles, and cats purr at those very same frequencies.

Remediation of other illnesses due to the cat’s purring ability is also being put forward. For example, respiratory problems associated with heart disease in cats are almost non-existent. In fact, respiratory problems resolve quickly once purring is activated. Dr. T. F. Cook in 1973 wrote the article “The Relief of Dyspnea In Cats By Purring” in the New Zealand Veterinary Journal (dyspnea is the condition of difficulty in breathing). It seems a dying cat had such difficulty breathing that the vets were considering euthanasia. But the cat was found to begin breathing normally once it began to purr! The purring appeared to open up the cat's air passages.

Domestic cats are generally less prone to postoperative complications following surgeries. Other healing mechanisms associated with purring include large skin-tissue grafts that take quickly in cats without necrotizing. The list just continues on and on.

In effect then, by changing the frequency of their purring, cats may be fine-tuning their healing abilities, and it is this unique healing advantage that has probably given rise to the notion of cats having nine lives. They survive conditions that normally kill other animals, such as falls from heights. In a study of 132 cat falls with an average fall height of 5½ stories, 90% survived. The record height for a cat falling and surviving is 45 stories!

Muggenthaler concludes that such “an internal healing mechanism would be advantageous, increasing recovery time and keeping muscles and bone strong when sedentary.”

Vibrational Purr Therapy?

The extrapolation of this research may prove vital. Studies continue regarding tissue exposure to frequencies between 20-50 Hz. For example, Dr. Clinton Rubin in a 1999 study discovered that such exposure creates the robust striations of increased bone density, suggesting applications for osteoporosis, particularly in post-menopausal women and the elderly.

Ukrainian and Russian researchers discovered the benefits of using vibratory stimulation many decades ago and have employed these techniques in sports training and sports medicine. Since the fall of the Iron Curtain, many of the treatment devices used by the Soviets have made their way into Western gyms and physical therapy treatment centers.

Even the space program has found a benefit from the research. This breakthrough could help astronauts, who generally loose bone density in zero gravity, in maintaining healthy bones and resisting the problems of atrophy in outer space.

But it’s the cat’s “healing by association” that most people find interesting: that ability of a cat to sympathetically help cure illnesses in people simply by being around them. Studies have also shown that owners, especially senior citizens, who have cats have lower blood pressure and can live longer than humans who don't own pets.

Many individuals swear they can ease or completely eliminate their migraine headaches simply by lying down with a purring cat next to their head.

Can’t hit that minimum recommended daily dose of bone-enriching calcium? Maybe grabbing the nearest cat and holding it close may just prove to be the answer to brittle-bones.

Having surgery? Perhaps after coming home, keeping a cat nearby will reduce your recovery time.

So, go get a cat. Keep it happy and purring. You’re both likely to be healthier and you’ll have a great friend who truly understands how you’re feeling.

Lev G. Fedyniak, MD began his medical career in alternative medicine, studying acupuncture, herbs and other healing traditions in China, Hong Kong, Canada, Ukraine and other parts of the world. Recognizing that the allopathic tradition was a necessary component in treating illness, he trained in allopathic medicine to obtain the Doctor of Medicine (MD) degree.

Dr. Lev makes his home in Ukraine and continues to study new approaches to treating illness and optimizing health from traditions all over the world. He publishes articles and books in the hopes of bringing such information to all who need it.


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