Under the Microscope: We recently got a Bichon Frise puppy called Milo who has made a major impact on our lives. Our daily routines are now fully synchronised with Milo's routine of waking, sleeping, eating, exercising, and, of course, relieving himself of his number ones and twos. I haven't noticed any marked improvement in my health yet, but there is much evidence that owning and living with a pet is good for your health, both physically and mentally, writes Prof William Reville
The reason why having a pet, particularly a dog or a cat, is good for your health is still not known. One would guess that the correlation is underpinned by emotional benefits. Each of us has a basic need to give and receive love and affection. Keeping a pet is one way of meeting these needs, and, for elderly people, may often be the main way. It is well known that stress makes you susceptible to illness, so anything that relieves stress, such as the unconditional affection you receive from your dog, or the exercise you receive from walking him, will have a positive effect on your health.
Social science surveys have consistently correlated pet ownership with better health. A huge German survey carried out between 1996 and 2001 found that people who keep pets visit their doctor 10 per cent less often than people who don't keep pets. An American study of heart attack victims showed that those with pets at home were twice as likely to survive for a year. One reason proposed to explain this was that stroking a pet causes the brain to release endorphins, natural opiates that make you feel good. The endorphins calm the nervous system and lower the heart rate. Even watching fish swimming in a tank has a calming effect.
A British study noted the effect of giving a pet to people who had not recently owned one, following their lives for 10 months. The new pet owners showed improvements in physical and mental health and dog owners took more exercise. Another Australian study showed that male pet owners had lower blood cholesterol levels than non-owners.
In a study presented at the 1999 annual meeting of the American Heart Association, Dr Karen Allen, a medical researcher at the State University of New York, found that stockbrokers suffering from high blood pressure showed lower blood pressure readings in stressful situations after adopting a dog or a cat than did their counterparts who had no pets. Allen doesn't known why pets lower blood pressure but surmises - "having something on your side, something you can always count on to be non-judgmental, psychologically creates a beneficial atmosphere".
The psychosocial effects of having a pet around are fascinating. It has been reported, for example, that Alzheimer's patients have fewer anxious outbursts if there is an animal in the home. Their care-givers also feel less burdened when there is a pet around, particularly a cat, which requires less care than a dog. Another study showed
that pet owners cope better with adverse life events (eg bereavement) than people who don't have pets.
Some research has indicated that dogs can detect epileptic seizures in their owners before they happen and before the owner has any personal indication that a seizure is on the way. Other work has indicated that dogs can detect the dangerous skin cancer called melanoma by smell and also bladder cancer by smelling urine. The success in detecting bladder cancer has been published in the British Medical Journal, 25 September 2004, by Carolyn Willis and others.
Many people who are vulnerable to anxiety or depression suffer less if they have a pet compared with similar people living without pets.
Recent research has also shown that pet owners who contract Aids are much less likely to suffer from depression than those without pets.
There are many stories about the unconditional love that dogs feel for their owners. One of the best known is the story of Greyfriars Bobby. John Grey served with the Edinburgh police in the early 1800s. It was a condition of service that the constable have a watchdog. He obtained a sky terrier and named him Bobby. Total companionship developed between Grey and Bobby. John Grey died in 1858 and was buried in Greyfriars churchyard.
For 14 years, Bobby kept constant watch and guard over the grave until his own death in 1872. Bobby lay on the grave, leaving only for food. People gathered daily at the entrance to the churchyard waiting for the 1pm gun to trigger the appearance of Bobby leaving for his mid-day meal.
Many species of animals have been successfully cloned. Dogs are particularly difficult to clone, but in April 2005, Prof Hwang Woo-suk at Seoul National University introduced Snuppy, claiming it as the world's first cloned dog.
Snuppy is a shaggy Afghan hound and was born by Caesarean section to a Labrador surrogate mother on April 24th. Woo-suk explained that the purpose of this work is not to copy people's pets but to study human disease using animal models.
Of course pets are not for everyone. A minority of people just don't like animals and are therefore unlikely to benefit from adopting a pet.
Also, people with allergies to dogs or cats are not encouraged to acquire them. People who suffer from asthma are advised against keeping cats or dogs as pets. The fleas and ticks carried by cats and dogs can spread a range of diseases.
William Reville is associate professor of biochemistry and public awareness of science officer at UCC - http://understandingscience.ucc.ie