Health benefits for humans

The scientific evidence is mixed as to whether companionship of a dog can enhance human physical health and psychological wellbeing.[91] Studies suggesting that there are benefits to physical heath and psychological wellbeing[92] have been criticised for being poorly controlled,[93] and finding that "[t]he health of elderly people is related to their health habits and social supports but not to their ownership of, or attachment to, a companion animal." Earlier studies do show that dog and cat owners have been shown to have better mental and physical health than nonowners, making fewer visits to the doctor and being less likely to be on medication than nonowners.[94] However, "recent research has failed to support earlier findings that pet ownership is associated with a reduced risk of cardiovascular disease, a reduced use of general practitioner services, or any psychological or physical benefits on health for community dwelling older people. Research has, however, pointed to significantly less absenteeism from school through sickness among children who live with pets."[91] In one study, new pet owners reported a highly significant reduction in minor health problems during the first month following pet acquisition, and this effect was sustained in dog owners through to the end of the study.[95] In addition, dog owners took considerably more physical exercise than cat owners and people without pets. The group without pets exhibited no statistically significant changes in health or behaviour. The results provide evidence that pet acquisition may have positive effects on human health and behaviour, and that for dog owners these effects are relatively long term.[95] Pet ownership has also been associated with increased coronary artery disease survival, with dog owners being significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs.[96] Gunnar Kaasen and Balto, the lead dog on the last relay team of the 1925 serum run to Nome. The health benefits of dogs can result from contact with dogs, not just from dog ownership. For example, when in the presence of a pet d

g, people show reductions in cardiovascular, behavioral, and psychological indicators of anxiety.[97] Other health benefits are gained from exposure to immune-stimulating microorganisms, which, according to the hygiene hypothesis, can protect against allergies and autoimmune diseases. The benefits of contact with a dog also include social support, as dogs are able to not only provide companionship and social support themselves, but also to act as facilitators of social interactions between humans.[98] One study indicated that wheelchair users experience more positive social interactions with strangers when they are accompanied by a dog than when they are not.[99] The practice of using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders.[100] Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase a person with Alzheimer’s disease’s social behaviours, such as smiling and laughing.[101] One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives, and decreased antisocial and violent behavior compared to those who were not in an animal-assisted program. In medicine, the hygiene hypothesis states that a lack of early childhood exposure to infectious agents, symbiotic microorganisms (e.g., gut flora or probiotics), and parasites increases susceptibility to allergic diseases by suppressing natural development of the immune system. It is hypothesized that the TH1 polarized response is not induced early in life leaving the body more susceptible to developing TH2 induced disease.[1] The rise of autoimmune diseases and acute lymphoblastic leukemia in young people in the developed world has also been linked to the hygiene hypothesis.[2][3] There is some evidence that autism may be caused by an immune disease;[4] One publication speculated that the lack of early childhood exposure could be a cause of autism.