How good is exercise that feels effortless?

The 'zone zero' fitness trend promotes very low-intensity movement, like walking and housework. Here's what it can and can't do for you.

- Danielle Friedman

When you're exhausted, burned out or short on time, the notion of slipping on gym clothes and pushing yourself to work out can feel impossible.

But a casual stroll or stretching session might not seem out of reach.

A new fitness trend has rebranded these super low-intensity forms of movement as “zone zero” exercise. The term is a nod to heart rate zone training, a framework that divides physical activity into five zones that reflect different levels of aerobic effort.

As the name suggests, zone zero training is meant to be so easy it feels almost effortless, and it generally refers to any activity in which your heart rate stays below half of its maximum capacity. (To estimate your max heart rate, subtract your age from 220.) Think: Taking an ambling walk after dinner, going for an easy bike ride, playing with your kids or doing light housework.

"It's a new term for an old concept," which is that any amount of physical activity is good for you, said Dr Julia Iafrate, a sports medicine physician at NYU Langone Medical Centre. Many people can benefit from a no-stress approach, she added, especially if they're used to "no pain, no gain" fitness messaging that suggests the only workout worth doing is one that feels like work.