The promise sounds too good to be true: your body will feel better, and you’ll have less inflammation. You won’t worry as much, and you’ll be calmer. Is this a fad diet or miracle drug? Nope. It’s helping others.

Current research focuses on “givers” who benefit simply from the act of lending a hand. Labor economist Richard Layard recently determined, “Doing kindness makes you happier and being happier makes you do acts of kindness.” A win for the chicken, a victory for the egg.

The kindness movement emerged in response to tragedy. In 1982, writer Anne Herbert heard “random acts of violence and senseless acts of cruelty” one too many times on the evening news. Sitting in a California restaurant, she rewrote that phrase as “random acts of kindness and senseless acts of beauty.” Her notes on a placemat launched a rebellion of goodness. Other Americans, tired of only hearing about crime and destruction, took action to become intentionally more generous to strangers. The first part of Herbert’s slogan caught on so much that 38 years later if anyone was asked to complete the phrase “random acts of ... ” the most prevalent response would be “kindness.”

We’re in the midst of a pandemic, a financial crisis and a fight for racial justice. Surprisingly, kindness is a hot subject in scientific circles. Evolutionary anthropologist Brian Hare and science writer Vanessa Woods’ just-published book “Survival of the Friendliest: Understanding Our Origins and Rediscovering Our Common Humanity,” claims that compassion and cooperation are keys to human development and survival. We need each other and always have, a sentiment older than religion or even the family unit.

We live in polarized times. Some say our country has not been so divided since the Civil War. Blue and red rifts run deep.

Still, there are reports of everyday-people using whatever they have to give in whatever ways. Two recent examples are particularly poignant. A line of two dozen white women used their bodies as a human shield to protect demonstrators of color from police during a peaceful protest seeking justice for Breonna Taylor, a dispatcher shot dead in her bed in Louisville, Kentucky. Two days later — same city, same Black Lives Matter protest — three black men stepped out of an angry crowd to lock arms and encircle a patrol cop who was separated from his team. A white man and a Dominican man joined them, and the five walked officer Galen Hinshaw safely to his squad. Later he said, “They saved me. It was a moment where strangers came together to help another stranger, and that stranger was me.” One protector, Ricky McClellan, responded, “A human was in trouble, and right is right.”

Many of us think we’d be one of the “good guys” who steps up when needed, but that’s rare. Research on the bystander effect shows that the larger a group, the less likely for someone to help. The diffusion of responsibility prompts an expectation that others will assist, which too often means no one does.

The American Red Cross counts upon Good Samaritans and asks potential donors to “turn compassion into action.” This ideology is what the Greatest Generation embodied: they understood the fight for a common good. My father donated gallons of blood throughout his 10 decades, something he viewed as part of his civic duty along with supporting the union, voting in every election and paying taxes. When I was 8 years old, Dad got a call from St. Joseph’s in Chippewa Falls to come in for an emergency donation. A car accident meant his rare B negative was in demand. That may have been the first time I realized we all have something inside of us that others need.

Every 15 seconds an ailing American requires a platelet transfusion. I made my first-ever donation in April after COVID-19 shut down Red Cross blood drives. I recently went in again after reading that there is still an extreme shortage.

Though it takes longer, giving platelets means a much smaller needle than giving blood, and most donors do not feel as sluggish afterward since the only parts removed are platelets, those tiny cells that help form clots and stop bleeding.

Phlebotomist Cassie pricks my finger and says sweetly, “This is always the worst part.” After my initial hemoglobin screening, I feel one little pinch on each vein as she slides in the needle. Then nothing. My blood churns out one arm and spins through a centrifuge machine to separate my platelets. This life-saving goo will be used to help cancer patients and people fighting chronic diseases or traumatic injuries. The short shelf life, five days, means these platelets stay local. The rest of my blood — plasma, red and white cells — returns to my body via my other arm.

For me, the worst part is the balancing act between drinking enough water to plump up my veins but not so much that my bladder won’t feel like exploding during the two-hour procedure. While I’m hooked up, I watch “Flags of Our Fathers.” The story of Antigo, Wisconsin’s John “Doc” Bradley and other soldiers on Iwo Jima during WWII portrays how young men were called upon to sacrifice for our country. Almost 7,000 soldiers died fighting on that Pacific island. On day five of the 36-day battle, six men raised the American flag. The scene was captured in Joe Rosenthal’s iconic photograph turned war memorial. The image was also used in a Treasury Department campaign with the slogan “Now — All Together.” In 1945 this appealed to a patriotic spirit and a respect for teamwork. Millions of Americans purchased war bonds — pay $18.75, then redeem after 10 years for $25 — which earned $156 billion for a country in need. Today that’s the equivalent of over $2.25 trillion.

Why write about this 75 years later? Because there are always many calls to duty. Each of us can do something, now and all together. It’s easy to help the ones we love. The real challenge is showing compassion to strangers or even perceived enemies. Donate, give, share, reach out, step up, be kind.

These acts seem insignificant, but collectively they make a world of difference. An added bonus: Science now tells us the life you improve may be your own.