Perhaps the fastest growing demographic for American households is the number of pets. From fuzzy creatures to scaled aquarium dwellers and everything in-between, the number of households with pets has been on a steady multi-decade climb. According to the most recent annual survey by the American Pet Products Association , 67% of US households, almost 85 million homes, own one or more pets, an increase of almost 34 million households since 1988. This year marks the 40th anniversary of the publication  of a seminal study on the health impacts of pet ownership marking one of the earliest scientific efforts to assess how pet ownership can affect our physical and mental wellbeing.
The leading research agency dedicated to understanding how pets, and animals in general, and humans interact is the Human Animal Bond Research Institute (HABRI) based in Washington DC . This group has a broad research agenda that includes not only pets but also therapeutic and service animals. In 2015, we were engaged by HABRI to review the historic and emerging literature on the health benefits of pet ownership and, where data allowed, to estimate the healthcare cost savings associated with these benefits. Even with substantial data limitations, we found the health improvements associated with pet ownership lowers healthcare spending by billions of dollars each year. In honour of that pioneering 1980 study, we want to call attention once again to the physical and mental health and wellness benefits associated with pet ownership.
In 1980, Erika Freidmann and her colleagues published research showing that pet owners exhibited better long- term survivability after heart attacks. Though the authors did not claim definitive causation, largely due to a lack of theoretical understanding of the human-animal bond, the findings were suggestive that these realised benefits came through physical mechanisms (physically activity associated with pet care) and psychological effects (companionship).While these findings are important by themselves, the larger benefit was setting the stage for the development of a new field of study, resulting in deeper understanding and improved health outcomes for humans based on their interactions with animals.
In our research, we reviewed the relevant literature on health benefits of pet ownership in studies that reflected the traditions of Western medicine. We also explicitly excluded the economic value of physical and mental health improvements from therapeutic animals, which can range from treatment of autistic children to helping veterans deal with PTSD, and service animals, which effectively allow individuals with physical challenges to lead more productive economic lives. In quick-hitting fashion, here are some key research findings from the literature.
The studies we reviewed found a notable drop in the number of physician office visits per year for pet owners versus non-pet owners.Though there was variation in the findings, the most conservative decline was an 11% decrease in office visits. 
In 2013, the American Heart Association (AHA) issued a Scientific Statement  offering a comprehensive review of studies on the effects of pet ownership on cardiovascular disease. We have augmented the work reviewed by AHA with more recent studies. While the totality of all research is mixed, the weight of recent research is turning towards confirmation that pet owners tend to exhibit lower blood pressure. In a 2017 study, hypertensive elders who own pets also had improved life spans.  The AHA statement also reports a few studies that observe clinically modest improvements in blood cholesterol associated with pet ownership. In a recent Mexico-based study, researchers found that older adults with a companion dog have both lower cortisol and total cholesterol. 
PHYSICAL ACTIVITY AND OBESITY
In addition to the previously mentioned 1980 study, there are several reports that associate pet ownership and exercise levels. These studies often focus on dogs, but one recent study noted the benefits of horse ownership. A detailed study found that the incidence of obesity is 17% for dog walkers, 22% for non-owners and 28% for dog owners who do not walk their dog. A more recent meta-analysis of this specific area of study finds the impacts of pet ownership collectively on obesity is not statistically significant but made no overt distinction between those that exercise their animal and overall pet ownership. Have you walked your goldfish lately?
Stress: Owning a pet reduces reactivity stress for individuals in high- stress occupations. Blood pressure, heart rate and plasma renin activity
all decreased after having a pet for six months.This literature covers many types of pets including chimpanzees, fish, goats and snakes.
Nutrition Supplements: A Purdue University study  found that placing an aquarium in a memory care facility boosted patient food intake resulting in a decreased need for food supplements.
Allergies: Several studies have found that early childhood exposure to dogs or cats lowers the likelihood of developing pet allergies later in life, though at least one study found no impacts, positive or negative, on childhood asthma or pet allergies.
Perhaps the most exciting work in assessing the impacts of human-animal bonds on owners’ health falls under a broad category of mental health. Pets can be a source of comfort for everyday stress, significant loss events (death, disasters) and in recovery from a variety of maladies.We believe that this is especially important in the time of COVID-19.The loss of social companionship and related mental health maladies, especially among the at-risk population who have had to endure separation from family and friends for months, can be greatly reduced by having a companion pet.
HEALTHCARE COST SAVING
Even though the supporting literature did not allow us to estimate the healthcare cost savings associated with all of the maladies listed above, we did have data on the costs of physician office visits and the cost to treat obesity-related diseases. For obesity, we used data to only account for the improvements in body mass for dog owners who report walking their dog at least five days each week. In 2020 dollars, we estimate that the US healthcare system and consumers realise more than $12 billion per year in pet-ownership related savings. But for those of us who own pets, the fun and joy of a companion animal is truly priceless.
Terry L Clower and Tonya E Thornton / Pets and Our Health
- American Pet Products Association; Pet Industry Market Size & Ownership Statistics. See https:// www.americanpetproducts.org/ press_industrytrends.asp
- Freidmann E, Katcher A, Lynch J and Thomas S (1980). “Animal Companions and One-Year Survival of Patients after Discharge from a Coronary Care Unit.” Public Health Report, 95(4): 307-312.
- Human Animal Bond Research Institute (HABRI). See https://habri. org/
- Heady B and Grabka M (2007). “Pets and Human Health in Germany and Australia: National Longitudinal Results.” Social Indicators Research, 80(2): 297- 311. Siegel J (1990). Stressful Life Events and the Use of Physician Services among the Elderly: “The Moderating Effects of Pet Ownership.” Journal of Personality and Social Psychology, 58(6): 1081–1086.
- Levine G, et al, (2013). “Pet Ownership and Cardiovascular Risk: A Scientific Statement from the American Heart Association.” Circulation, 127(23): 2353-2363.
- Chowdury H (2017). “Pet ownership and survival in the elderly hypertensive population.” Journal of Hypertension, 35(4), 769-775.
- Morales-Jinez A, et al (2018). “Allostatic Load and Canine Companionship: A Comparative Study Using Biomarkers un Older Adults.” Revista Latino-Americana de Enfermagem, 26, e3071.
- Lakdawalla P (2003) “Sea-ing results: An Aquarium can Help Boost Alzheimer’s Patients’ Appetites.” Contemporary Long- Term Care, 26(7): 28.