Can pets really boost your immune system?

Research increasingly suggests that the answer may be yes—though with important caveats. From childhood allergies to stress management, scientists are uncovering new links between pet exposure and immune health. However, as with many health-related topics, the reality is nuanced and context matters.

Microbes, Pets, and the Hygiene Hypothesis

One of the most compelling scientific arguments in favour of pets benefiting immunity is grounded in the "hygiene hypothesis." This theory suggests that early exposure to a diverse range of microbes—often found in outdoor environments and, interestingly, on pets—helps the developing immune system distinguish between harmful and harmless agents. Without this exposure, some scientists believe, the immune system may become hyper-reactive, increasing the risk of allergies and autoimmune conditions.

A study published in the New England Journal of Medicine found that children who grew up on farms or in households with multiple pets had lower rates of asthma and allergies compared to those in pet-free urban settings. Dogs, in particular, bring in dirt and bacteria from outside, effectively diversifying the microbiome of a household.

The BBC’s Future article, “How Your Pets Alter Your Immune System,” also highlights how dog ownership reshapes the human microbiome in measurable ways. Some bacterial strains found on pets transfer to their owners, particularly through touch or close proximity. While that might sound off-putting to some, it's a form of natural microbial exposure that may condition the immune system, especially in early life.

Stress, Hormones, and Immune Response

Another biological pathway through which pets might influence immunity is stress regulation. It is well-established that chronic stress can weaken the immune system by elevating cortisol levels, which in turn hampers the body's ability to fight off infections.

Numerous studies show that interacting with pets—whether by petting a cat, walking a dog, or simply being in the presence of an animal—lowers cortisol and boosts oxytocin, the so-called "bonding hormone." These changes may not only improve mental health but also support a more balanced immune response.

In this context, pets are more than just mood lifters—they may be functional allies in the fight against stress-related health issues.

The Role of Physical Activity

Pet ownership, especially of dogs, often leads to increased physical activity. According to the NHS, adults should aim for at least 150 minutes of moderate activity per week. Dog owners, who walk their pets regularly, are more likely to meet or exceed these targets.

Exercise, in turn, has a well-documented effect on immune health. It improves circulation, helps regulate inflammation, and may slow age-related immune decline.

Thus, the indirect benefits of pet ownership—via lifestyle changes—can be just as significant as any microbiological influence.

Considerations and Limitations

Despite the promising research, it’s important to exercise caution. For people with compromised immune systems or existing allergies, living with animals can present genuine risks. Zoonotic diseases—those that pass from animals to humans—are rare but possible, particularly if proper hygiene isn’t maintained.

Furthermore, the benefits of pet ownership are not uniform across all individuals. Factors such as age, health status, pet type, and environmental conditions all play a role. Experts advise consulting healthcare professionals before bringing a pet into homes where immune vulnerability is a concern.

What Experts Are Saying

Professor Susan Lynch, an immunologist at the University of California, tells the BBC that our "microbial exposures have changed dramatically" in the modern world. “Pets, especially dogs, serve as a microbial bridge to the outdoors,” she says, “which may be essential for immune calibration.”

Meanwhile, the British Veterinary Association (BVA) encourages pet ownership but also emphasises responsible care: “Pets can improve our lives in many ways,” a spokesperson said, “but it’s important to understand both the benefits and responsibilities involved.”

Conclusion

While no pet should be seen as a medical treatment, growing scientific evidence suggests that the presence of animals in our lives may have broader health benefits—particularly for our immune systems. From enhancing microbial diversity to lowering stress and increasing physical activity, pets may play a quiet yet crucial role in human well-being.

However, as with all health matters, individual needs and circumstances vary. Prospective pet owners should weigh the benefits alongside possible risks and consult relevant health or veterinary professionals.

In an age where immunity has become a public health focus, perhaps our furry companions offer more than love—they might just help us build stronger defences, one paw print at a time.

This article is based on current research and is intended for informational purposes. Individuals should consult healthcare professionals for personalized medical advice.