Hiroaki Tanaka wants you to smile while jogging.

That sometimes seems impossible — especially when people sprint past on a running path as you’re chugging along slowly.

But according to Tanaka, a professor at the Faculty of Sports and Health Science at Fukuoka University in Japan, there may be health benefits to jogging slowly.

Tanaka wrote “Slow Jogging: Get Fit, Lose Weight, Stay Healthy, and Have Fun With Easy Running” with Magdalena Jackowska. He has implemented slow jogging to run multiple marathons — and has a unique suggestion: Run only as fast as your body lets you smile.

He calls this a “smiling pace,” or a “niko niko pace,” and says the best way to run is at a calm speed, which helps lower blood pressure while boosting overall fitness.

Tanaka said that to find what pace might be for you, consider starting slow and listen to your body.

“Niko niko pace can be very different for each one of us,” he said. It might even be lower than your walking speed.

To help visualize the best pace, think of a time when a traffic light is about to turn red and you pick up the pace to make it across the street.

“It’s one of the moments when even the least fit of us start running,” Tanaka writes. This running-to-the-light pace is usually about 4.3 miles per hour, according to the authors.

They recommend starting very slow — perhaps at about 2 to 3 miles per hour.

The exact speed isn’t important. Instead of worrying about calculating your pace, take a simple test: If you are too short of breath to hold a conversation, back off.

“Slow down to be able to talk at ease, or if you are running alone, sing your favorite songs,” Tanaka said.

Tanaka and Jackowska found that even a group of 75-year-olds experienced lowered blood pressure from slow jogging.

“It’s never too late to start,” he said.