For couples, simple touching has a range of mental and physical health benefits.

Whether it’s a few moments spent holding hands, a hug hello, or cuddling on the couch, simple touches from those we care about can bring a smile to our face — even on our most difficult days.

However, being touched by those we love doesn’t merely feel good. Studies show simple touch is also good for our mental and physical health.

“If someone [you trust] holds your hand or hugs you or gives you a back massage before you have a stressful task like giving a speech, your heart rate slows, blood pressure lowers, and your stress hormones will decrease,” Tiffany Field, PhD, director of the Touch Research Institute at the Leonard M. Miller School of Medicine at the University of Miami, told Healthline. “There’s also an increase in oxytocin, which is the love hormone that contributes to relaxation in couples.”

As a result of de-stressing, research has shown soothing touch can also help build your immune system.

“There’s this whole body of literature around the stress response and how chronic stress literally impairs everything from brain functioning to your immune system. When you’re under a lot of stress, cortisol is released and your immune system tanks, allowing you to get sicker,” said Dr. Amy Banks, a psychiatrist based in Lexington, Massachusetts, and author of “Wired to Connect: The Surprising Link Between Brain Science and Strong, Healthy Relationships.”

To better understand the connection, Banks pointed to the evolution of humankind.

At one time, creatures gave birth to many eggs. When born, the creatures had to fend for themselves for survival, yet only few of the many would live on.

“Once we became mammals, we kept the babies inside of us and so we had fewer of them. Their chances of survival were dependent on us being in a social context — a parent taking care of their offspring,” Banks said. “Biologically, our whole nervous system and immune system functioning became dependent on being in a relationship, a society, a community, where the younger, smaller, weaker could be protected until they grew up.”

Around this time, she says the smart vagus nerve evolved. This is part of the autonomic nervous system and modulates the entire stress response system, called the sympathetic nervous system.

“The smart vagus nerve tells our sympathetic nervous system to stand down, you’re not needed,” explained Banks.

For instance, when a person feels safe and connected to another person, their facial expressions may create a smile, and the muscles in their inner ears open up, so that they listen more attentively. Both of these reactions are stimulated by the smart vagus nerve.

From birth, babies have a desire for social connection. Banks pointed to the mother-infant gaze, which refers to the interactions between a mother and her baby in a healthy relationship.

“Literally the mother and infant become synchronized when they interact with each other,” said Banks. “As they engage, the baby gets stimulated and then looks away as a way to modulate the stimulation. In response, an in-tune mother will do the same thing. Then they’ll re-engage.”

She says this connection over the first few years of life helps to build the capacity for future safe relationships by building pathways for serotonin — the body’s anti-pain and antidepressant chemical — dopamine, oxytocin, and even opioids, which help the body regulate mood, affects, and even pain.

“The touch, the holding, and cuddling are all shown to stimulate these pathways needed for connection,” Banks said.

Consider the Harlow’s Monkey Experiment conducted by American psychologist Harry Harlow, which observed rhesus monkeys and how isolation and separation can affect them later in life. The experiment proved that creating a bond between a monkey and its mother required both physiological needs, such as warmth, safety, and food, as well as emotional needs including acceptance, love, and affection.

During the experiment, monkeys were taken from their mothers within 12 hours of being born and put into a room with inanimate mothers. One mother was made of wire mesh and one was made of wood covered in terry cloth. The monkeys could get milk from both.

In the first experiment, the monkeys were free to go to either of the moms, but spent more time cuddling with the terry cloth mother. In the second experiment, the monkeys were placed with one of the moms. When put into stressful situations, the monkeys with the terry cloth mom would cuddle with the mom until they calmed down. However, the monkeys placed with the wire mesh moms didn’t go to it for comfort, and instead rocked themselves on the ground.

Harlow suggested that these results also apply to humans.

“This shows how we are built. Touch does all this great stuff in terms of releasing chemicals and giving us comfort,” Banks said.

Christine Proulx, PhD, associate professor in the department of Human Development and Family Science at the University of Missouri, agreed, stating that from birth, we have a physiological response to touch.

“There’s a reason why there’s a big push to immediately put a baby on a mother’s chest and why people volunteer to hold babies in the neonatal intensive care unit. We’re hardwired for that skin-to-skin contact, and this carries over into adulthood,” Proulx said.

As adults, she said romantic relationships are one of the primary relationships that provide us with the touch we crave. “We ask for hugs because they benefit and soothe us, and so they have a health-promoting benefit in that sense,” she said.

Feeling connected also fends off loneliness, added Proulx. “There are lots of studies on how isolation and loneliness are detrimental to our health. Most human beings want to feel that someone loves and cares for them. Our close relationships can fill that desire,” she said.

For couples who are particularly close, Fields adds that touching can sync their physiological rhythms. “When they hold hands, their heart rates are in sync and their brain waves get in sync. It’s a phenomenon that happens,” Field said.

Emotional benefits are also intertwined.

“There are a lot of feelings that go along with receiving touch from your partner and most are positive feelings reflected in brain waves,” Fields said.

While the right front lobe is activated during negative or withdrawal-type emotions, the left side of the frontal lobe usually causes positive emotions.

“It’s been documented that the pleasure part of the brain is activated during touch,” said Fields.

In addition to the physiological and emotional benefits, Proulx says there’s also a practical component to feeling cared for and connected.

“If something happens, who can you call? If you fall and have no one to reach out to, your health is at risk. Feeling cared for certainly has an instrumental side to it too,” she said.

When sexual interactions are safe and consensual, Banks said people get all the benefits of touch too.

“There’s very good research that shows being in that kind of sexual encounter has tons of benefits. For example, you get big releases of oxytocin when you have an orgasm,” she said.

However, the same hormones are at play with nonsexual touching, such as cuddling, back rubs, back scratches, foot rubs, and holding hands. “All of these stimulate the same chemicals, maybe not at the same intensity [as an orgasm], but clearly they’re released,” Banks said.

So, the next time you reach for your partner’s hand, embrace them after a long day, or snuggle during a movie, remember, you’re not just showing them you care — you’re both getting a health boost too.