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Cuddling up to furry friends may reduce stress and even strengthen the immune system
Dogs and other kinds of pets can provide us with a variety of benefits.
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When Percy Lee has a bad day, he hangs out with his chinchilla, Rin. “She’s like emotional support for me,” says the 14-year-old. Percy, who lives near Kansas City, Kansas, and is the author’s nephew, particularly enjoys snuggling with Rin and watching her explore. “When I get upset and overwhelmed, playing with her is one of my main coping mechanisms,” he says.
Percy isn’t alone. After a long day, lots of people enjoy unwinding with their pets. They might find comfort in cuddling a cute cat or petting a playful pup. Even spending time with non-snuggly animals, like turtles or fish, gives many people a boost.
Kerri Rodriguez studies the bonds between people and animals at the University of Arizona in Oro Valley. “One of the biggest benefits of having a pet is that they never judge you,” she says. “They don’t care if you said something silly, if you have a ketchup stain on your shirt or if your breath smells,” Rodriguez says. Often, pets are simply happy to see us. They make us feel loved.
That animal affection may have benefits that go far beyond temporary mood boosts. Researchers like Rodriguez have found that pets can reduce stress, strengthen people’s immune systems and perhaps even help them learn. Understanding such perks better might inspire people to spend more time around animals, improving their mental and physical health.
Patricia Pendry is a developmental psychologist. At Washington State University in Pullman, she has spent years studying how stressful home environments affect kids’ health. That inspired her to search for ways to reduce children’s stress — including spending time with animals. In recent experiments, Pendry has investigated whether hanging out with animals has a measurable effect on the body’s stress system.
Pendry’s work focuses on a hormone called cortisol. The body makes more of that hormone when people are stressed. It makes less when people are calm. Pendry measures cortisol in the saliva of college students before, during and after spending time with animals. Sometimes the animals are specially trained therapy dogs that have been brought to campus. Other times, they are cats and dogs brought in by the local humane society.
When students arrive, they spit into a tube to provide a saliva sample. Then they spend the next 10 minutes doing one of four things. Some go into a room to pet the visiting animals right away. A second group watches the petting group while waiting in line. A third group looks at photos of the animals but doesn’t see them in person. The last group waits to get into the room without any glimpse of the pets. The students provide two more saliva samples to measure cortisol during and after that 10-minute window.
Students who petted the animals had lower cortisol levels at the end of the 10 minutes than any other group, the data showed. Interacting with animals reduces how much cortisol the body makes by boosting its levels of oxytocin (Ox-ee-TOH-sin), Pendry believes. Oxytocin is a hormone that helps calm the stress system.
“As you’re petting and stroking in this rhythmic way, your body makes oxytocin,” she explains. But people don’t even have to touch an animal to get that response. Simply making eye contact with a dog can raise a person’s oxytocin levels, other research suggests.
It’s only just become possible to measure oxytocin in spit samples like those that Pendry collects. So she hasn’t yet studied in detail how higher oxytocin levels might lower cortisol levels. But Pendry plans to see how both hormones respond to animal interactions in her next project.
The calming effect of animals can help some people overcome specific challenges.
For instance, there’s some evidence that reading aloud to dogs can help kids improve their reading skills. Reading to a dog is thought to provide support to students, helping them feel more confident in learning new skills.
In one 2020 study in Australia, researchers brought therapy dogs to four schools. First and second graders who struggled to read had one-on-one sessions with the dogs. They read to the animals, getting help from an adult as they needed it. Over the course of 12 weeks, the children improved their ability to read and felt more confident about reading.
Therapy dogs can help kids in other stressful situations, too. A 2021 study found that therapy dogs could reduce kids’ anxiety while they had their teeth cleaned at the dentist.
That doesn’t mean animals will make anyone feel calmer in any situation, Rodriguez says. “I know this is a bit of a bummer thing to say, but animals aren’t magical cures to everything.” In her research, Rodriguez is trying to figure out when animals can help and when they may not. Someday, she hopes people might use those interactions as an alternative form of medicine — treating anxiety with snuggle time the way they might treat a headache with Tylenol.
Rodriguez’s work has already shown how much service dogs can help people who have mental-health challenges. Service dogs aren’t simply pets. They’re specially trained to help their person. For instance, people who have experienced trauma may struggle with anxiety and other mental-health issues. Service dogs can help reduce those issues, Rodriguez has found.
Dogs don’t have to be specially trained to make a difference, others have found. One 2021 study of about 50 teens in Israel looked at the mood impacts of non-service dogs. Teens who spent one year training a dog, it found, experienced less anxiety and depression from post-traumatic stress disorder.
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Service animals also can help children with autism. Some kids with this disorder can become easily overwhelmed by sensory inputs. They may struggle to communicate with other people. A service dog can lean against them to provide calming pressure when they’re upset. Having a dog can also open up opportunities for a child to meet new people and socialize when other kids want to interact with their dog.
These dogs don’t just help the kids they’re assigned to, research by Rodriguez suggests. Knowing that a dog is looking out for their child can help parents rest easier, too. And that may aid relationships throughout the whole family.
It’s not just dogs that can offer emotional support to kids with autism. Kids with autism who interacted with a guinea pig were more likely to approach and interact with other people, a 2010 study found.
Kids may not have much control over whether they have animals at home. But those who do grow up with pets can be up to 40 percent less likely to develop asthma. And they may be 28 percent less likely to develop allergies. Those findings come from a 2020 study led by Mikael Knip. He researches child and adolescent health at the University of Helsinki in Finland.
In another study, his team found that growing up around dogs may cut in half someone’s chance of developing type 1 diabetes. In this disease, the immune system destroys cells of the body that make insulin, a hormone crucial to helping the body use food.
Allergies, asthma and type 1 diabetes all arise from problems with the immune system. Having pets may help prevent those conditions by strengthening kids’ immune systems.
The immune system is designed to fight off microbes, or germs, that could harm the body. But not all microbes are harmful. Early in life, the immune system must “learn” which germs cause harm and which don’t. When it develops properly, the immune system only attacks harmful germs. Without the right training, the immune system can start reacting to things — inside the body or outside it — that aren’t actually threats. That’s what happens when someone has allergies, asthma or type 1 diabetes.
Animals themselves probably don’t help train our immune system. “The idea is that early exposure to a dog or a cat in the house leads to an increased exposure to ‘healthy’ microbes,” Knip explains. All kinds of microbes collect on an animal’s paws and fur while they’re outdoors. The animal then brings those microbes home, which exposes family members to the germs. Those exposures help train up kids’ immune systems.
Pets that spend all their time indoors do not help protect against immune-based diseases, Knip notes. Animals need to bring outdoor germs inside to boost someone’s immunity. Larger animals, like dogs, seem to provide greater immune benefits than cats. “Dogs are, in general, bigger than cats,” Knip says. And they may “bring more microbes into the house.”
People seem to only get immune-system benefits from pets when they’re very young. In Knip’s diabetes study, for instance, kids had lower odds of developing diabetes only if there was a dog in the house when they were babies. “The first three years of life — and the first year in particular — are critical” for training the immune system, Knip says.
So if you’re reading this now, you’re already past that critical, early-life window. But if you grew up in a house with a big dog, you’ve probably experienced the immune benefits and didn’t even know it.
If you don’t have pets, how can you get some of their benefits? Talk to your family about getting an animal. “It’s really important to choose the right type of pet for you and your family,” Rodriguez cautions. Maybe a dog or cat isn’t an option. It may seem like too much work. In that case, “consider something like a turtle or a hamster,” she says. “These pets can still be really fun to interact with but come with a bit less responsibility.”
Even time spent watching a fish tank can provide some stress-relief. A 2023 study found that kids in the hospital were much less anxious and fearful when their room had goldfish in it.
If you can’t have a pet of your own, it’s possible to find other ways to interact with animals. “Talk to your neighbors, family members or friends,” Rodriguez suggests. “Can you volunteer to walk their dog for them one day a week? Maybe they have a cat or a bunny that needs [to be] played with?” You could even visit a cat café for a quick cuddle now and then, or volunteer at an animal shelter.
Interacting with animals can be rewarding, Rodriguez says. “But animals have feelings and emotions too! Remember to always respect an animal’s boundaries and personal space, just like you’d like to be treated.”
adolescent: Someone in that transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood.
anxious: (n. anxiety) A feeling of dread over some potential or upcoming situation, usually one over which someone feels they have little control.
asthma: A disease affecting the body’s airways, which are the tubes through which animals breathe. Asthma obstructs these airways through swelling, the production of too much mucus or a tightening of the tubes. As a result, the body can expand to breathe in air, but loses the ability to exhale appropriately. The most common cause of asthma is an allergy. Asthma is a leading cause of hospitalization and the top chronic disease responsible for kids missing school.
autism: (also known as autism spectrum disorders ) A set of developmental disorders that interfere with how certain parts of the brain develop. Affected regions of the brain control how people behave, interact and communicate with others and the world around them. Autism disorders can range from very mild to very severe. And even a fairly mild form can limit an individual’s ability to interact socially or communicate effectively.
cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.
cortisol: Also known as hydrocortisone, this is a hormone produced by the adrenal glands. It can serve as the body’s main warning that it is under stress. It helps regulate a wide range of body functions, including how we process the energy in food, create memories and control inflammation.
depression: A low spot, such as in a field or the surface of a rock. (in medicine) A mental illness characterized by persistent sadness and apathy. Although these feelings can be triggered by events, such as the death of a loved one or the move to a new city, that isn’t typically considered an “illness” — unless the symptoms are prolonged and harm an individual’s ability to perform normal daily tasks (such as working, sleeping or interacting with others). People suffering from depression often feel they lack the energy needed to get anything done. They may have difficulty concentrating on things or showing an interest in normal events. Many times, these feelings seem to be triggered by nothing; they can appear out of nowhere.
developmental: (in biology) An adjective that refers to the changes an organism undergoes from conception through adulthood. Those changes often involve chemistry, size and sometimes even shape.
diabetes: A disease where the body either makes too little of the hormone insulin (known as type 1 disease) or ignores the presence of too much insulin when it is present (known as type 2 diabetes).
disorder: (in medicine) A condition where the body does not work appropriately, leading to what might be viewed as an illness. This term can sometimes be used interchangeably with disease.
germ: Any one-celled microorganism, such as a bacterium or fungal species, or a virus particle. Some germs cause disease. Others can promote the health of more complex organisms, including birds and mammals. The health effects of most germs, however, remain unknown.
guinea pig: A rodent (Cavia porcellus) often kept as pets or used in research. Colloquial: A person or other animal that is used as an experimental subject.
hormone: (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body.
immune: (adj.) Having to do with immunity. (v.) Able to ward off a particular infection. Alternatively, this term can be used to mean an organism shows no impacts from exposure to a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.
immune system: The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.
insulin: A hormone produced in the pancreas (an organ that is part of the digestive system) that helps the body use glucose as fuel.
mental health: A term for someone’s emotional, psychological and social well-being. It refers to how people behave on their own and how they interact with others. It includes how people make choices, handle stress and manage fear or anxiety. Poor mental health can be triggered by disease or merely reflect a short-term response to life’s challenges. It can occur in people of any age, from babies to the elderly.
microbe: Short for microorganism. A living thing that is too small to see with the unaided eye, including bacteria, some fungi and many other organisms such as amoebas. Most consist of a single cell.
physical: (adj.) A term for things that exist in the real world, as opposed to in memories or the imagination. It can also refer to properties of materials that are due to their size and non-chemical interactions (such as when one block slams with force into another). (in biology and medicine) The term can refer to the body, as in a physical exam or physical activity.
post-traumatic stress disorder: Also known as PTSD, it’s a severe condition that may develop after a person is exposed to a traumatic injury or severe psychological shock. Recalling the event can bring on anxiety and other problems in the victim.
psychologist: A scientist or mental-health professional who studies the mind, especially in relation to actions and behaviors. Some work with people. Others may conduct experiments with animals (usually rodents) to test how their minds respond to different stimuli and conditions.
pup: A term given to the young of many animals, from dogs and mice to seals.
society: An integrated group of people or animals that generally cooperate and support one another for the greater good of them all.
stress: (in biology) A factor — such as unusual temperatures, movements, moisture or pollution — that affects the health of a species or ecosystem. (in psychology) A mental, physical, emotional or behavioral reaction to an event or circumstance (stressor) that disturbs a person or animal’s usual state of being or places increased demands on a person or animal; psychological stress can be either positive or negative.
system: A network of parts that together work to achieve some function. For instance, the blood, vessels and heart are primary components of the human body’s circulatory system. Similarly, trains, platforms, tracks, roadway signals and overpasses are among the potential components of a nation’s railway system. System can even be applied to the processes or ideas that are part of some method or ordered set of procedures for getting a task done.
therapy: (adj. therapeutic) Treatment intended to relieve or heal a disorder.
trauma: (in medicine) An injury, often a fairly severe one. This term also can refer to a severely disturbing incident (such as a car accident) or memory (such as the death of a loved one).
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Alison Pearce Stevens is a former biologist and forever science geek who writes about science and nature for kids. She lives with her husband, their two kids and a small menagerie of cuddly (and not-so cuddly) critters.
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