Why Do Cats Purr?
Research suggests that cats purr to trigger internal healing and strengthening in their body, and as a means of communication when they are content, happy, or stressed [1].
The frequency of a cat’s purr is between 20 to 150 hertz, a frequency research has shown capable of exerting various health benefits including bone growth, reduction in inflammation, production of new stem cells and much more [1][2].
Studies suggest that a cat’s low frequency purring vibrations can exert health benefits in both a cat’s body as well as their human or animal companions, which are thought to help both cats and humans to recover from injury or illnesses.
- February 25, 2023
- Dagmara Mach
THE SCIENCE OF WHY CATS PURR
Scientific evidence suggests that cats purr for a variety of reasons including as a means of self-healing and as a way to communicate with humans and other cats.
The pleasurable rasp of a cat’s purr often erupts when we pet, tickle or hold them. This purring thought to be a sign of contentment and relaxation.
Cats have also been observed to purr when they are in a relaxed state, such as when they are sleeping or grooming themselves.
Studies have shown that the frequency of a cat’s purr can lower a human’s stress level, heart rate and blood pressure, suggesting that cats may purr as a way to communicate and interact with humans in a therapeutic and calming way.
Additionally, cats have been observed to purr when they are in pain or experiencing discomfort. This is thought to be a way for the cat to self-soothe and manage pain.
Studies have also found that the vibrations produced by purring may have a multitude of healing properties, such as promoting bone growth, reducing inflammation and helping both cats and humans to recover from injuries and illnesses.
Cats have a complex communication system and researchers do not yet fully understand it. However, based on observation and scientific studies, it is clear that cats use purring as a way to communicate and interact with their environment in a variety of ways, including when they are happy and content, relaxed, or in pain or discomfort.
How Is A Purr Produced?
The sound of a cat’s purr is thought to come from the muscles within the cat’s larynx. As these muscles move, they dilate and constrict the glottis – the part of the larynx that surrounds the cat’s vocal chords – and the air vibrates every time the cat breathes in or out.
Health Benefits of a Cat's Purr
The health benefits of a cat’s purr, which falls within the range of 20-140 Hz, include stimulating bone growth and repair, reducing markers of inflammation, triggering new stem cell growth, releasing oxytocin and decreasing levels of the stress hormone cortisol [3].
Cat Purring May Boost Bone Growth
Evidence suggests that the vibrations produced by a cat’s purr may promote bone growth.
The discovery that the low frequency of a cat’s purr can increase bone density was made by a team of researchers led by Dr. Elizabeth von Muggenthaler, a bioacoustician.
In a study titled “Solving the Mystery of the Cat’s Purr Using the World’s Smallest Accelerometer” Dr. Elizabeth von Muggenthaler and her team investigated the mechanics behind the purring of cats and the potential therapeutic effects of their purring on human bones [3].
The study used a miniature accelerometer to measure the frequency and intensity of a cat’s purr, and found that it falls within the range that has been shown to stimulate bone growth and repair in humans.
The frequency range of a cat’s purr is typically between 20 and 150 Hertz, which falls within the range of healing frequencies that have been found to boost bone healing and density.
The vibrations produced by purring is thought to stimulate the growth and repair of bones, tendons, and muscles by increasing blood flow and encouraging the production of cells that are involved in the healing process.
Cat purring vibrations may also stimulate the release of hormones that help to reduce pain and inflammation, which can further aid in the healing process.
Current studies show promising results with regards to cat purring on bone growth, but more research is needed to confirm the findings and understand the mechanism behind it.
Lastly, although cats purring can promote bone growth, it doesn’t mean that it will heal fractures or any bone injury, it can help the healing process, but it is not a substitute for proper medical treatment.
Cat Purring May Reduce Inflammation
Vibrations produced by a cat’s purr may have anti-inflammatory effects, which may help to reduce inflammation in the body.
Studies have found that the frequency of a cat’s purr falls within a range that has been shown to have a positive effect on reducing inflammation.
The vibrations produced by purring may also stimulate the release of hormones such as endorphins and oxytocin, which can act as natural painkillers and have anti-inflammatory effects.
Additionally, the vibrations may also stimulate the production of cells that are involved in the healing process, which can further aid in reducing inflammation.
The vibrations produced by purring may stimulate the immune system, which can help to reduce inflammation and fight off infection.
Cat Purring Triggers Oxytocin Release
Cat purring has been shown to trigger the release of oxytocin in both cats and humans.
Oxytocin is a hormone that is produced by the hypothalamus and is released into the bloodstream by the pituitary gland. It is sometimes called the “love hormone” because it is associated with social bonding, trust, and feelings of love and well-being.
Oxytocin has been found to have anti-inflammatory effects in the body.
Studies show that oxytocin can reduce inflammation in a variety of conditions, such as cardiovascular disease, diabetes, and rheumatoid arthritis.
Oxytocin has been found to reduce the production of pro-inflammatory molecules, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 beta (IL-1beta). It also increases the production of anti-inflammatory molecules such as interleukin-10 (IL-10).
Oxytocin has also been found to have an effect on the immune system, it increases the production of white blood cells that help the body fight off infection and disease.
It also improves the function of natural killer cells, which are white blood cells that help to fight cancer cells.
Cat Purring Triggers New Cell Production
A cat’s purr may stimulate the production of cells that are involved in the healing process. Studies have shown that the frequency of a cat’s purr falls within a range that has been shown to have a positive effect on cell growth and repair.
Mesenchymal Stem Cells
One of the cells that are involved in the healing process are called “mesenchymal stem cells”. These cells have the ability to differentiate into various types of cells such as bone, cartilage, muscle and fat cells.
They also have the ability to promote the formation of new blood vessels, which is essential for the healing process. Studies have shown that vibrations within the frequency range of a cat’s purr can increase the proliferation and differentiation of mesenchymal stem cells.
Fibroblasts
Another cell involved in the healing process is called “fibroblasts”. These cells are responsible for the production of collagen and other extracellular matrix components that are needed for tissue repair.
Studies have shown that vibrations within the frequency range of a cat’s purr can increase the proliferation of fibroblasts and collagen production.
Cat Purring Decreases Cortisol
Cortisol is a hormone that is released by the adrenal glands in response to stress, and it plays a key role in the body’s stress response. High levels of cortisol have been associated with a variety of health conditions, including weight gain, insomnia, and heart disease.
Research suggests that the vibrations produced by a cat’s purr may have a calming effect on humans and may decrease levels of the stress hormone cortisol.
Studies have found that the frequency of a cat’s purr falls within a range that has been shown to have a positive effect on reducing stress and anxiety in humans.
One study found that when people petted a cat, their cortisol levels decreased and their mood improved.
Another study found that people who had a cat in their hospital room had lower cortisol levels and blood pressure than those who didn’t have a cat.
A third study found that people who had a cat had lower cortisol levels and felt less stressed than those who didn’t have a cat.
The cat purr vibrations also stimulate the release of hormones such as oxytocin and endorphins, which can act as natural painkillers and have calming effects on the body.
Research Sources
- von Muggenthaler, E. (2001). The felid purr: A healing mechanism?. The Journal of the Acoustical Society of America, 110(5), 2666-2666.
- Klotter, J. (2002). Vibrational frequencies that heal. (Shorts). Townsend Letter for Doctors and Patients, (226), 28.
- von Muggenthaler, E., & Wright, B. (2003). Solving the Mystery of the Cat’s Purr using the World’s Smallest Accelerometer. Acoustics Australia, 31(2), 69-69.
- Luo, F., Hou, T., Zhang, Z., Xie, Z., Wu, X., & Xu, J. (2012). Effects of pulsed electromagnetic field frequencies on the osteogenic differentiation of human mesenchymal stem cells. Orthopedics, 35(4), e526-e531.
- Safavi, A. S., Sendera, A., Haghighipour, N., & Banas-Zabczyk, A. (2022). The Role of Low-Frequency Electromagnetic Fields on Mesenchymal Stem Cells Differentiation: A Systematic Review. Tissue Engineering and Regenerative Medicine, 1-14.
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