This is the zone 2 treadmill workout Chris Hemsworth's coach uses to train for longevity

Age waits for no man—even A-listers like Chris Hemsworth. Now that the Australian actor has edged into his fourth decade, the 41-year-old has had to adapt the way he exercises, according to his long-standing PT. And anyone hoping to hold a candle to his impressive physique would do well to follow his lead.

"As you get older you have to train for longevity and think long-term," Centr trainer Luke Zocchi tells me, speaking from the set of Amazon Prime production Crime 101. "I hate to admit it but I'm 40 now and as I've got older I've definitely had to listen to my body more."

Childhood friends Zocchi and Hemsworth regularly train together to get the Thor star in shape for upcoming projects but the way they approach workouts has had to mature as the two have grown older. "Back in the day it was cardio in the mornings and pump weights six days a week. It was like more, more, more," says Zocchi.

Then a chance meeting with Rafael Nadal's physio while shooting for the film Extraction in the Czech Republic provided the wake-up call the duo needed to dial back their training.

"He hung out with me and Chris for a week and at the end was just like, 'You guys are mad. I've seen how much you train and how little rest you're getting. You're trying to work out like athletes but you're not following any of the recovery protocols'," Zocchi recalls.

"It was some really good insight," says Zocchi. "You know, we're no spring chickens. More isn't always better. You've got to be smarter."

Now if he's not feeling his best—or if Hemsworth has had a long day of shooting—Zocchi will swap in a lighter workout so they're both feeling fresh and ready to train harder tomorrow. "I used to be all or nothing. Every session. I'd just grind myself into the ground. Now I focus a lot more on rest and recovery, on quality over quantity."

One session the pair regularly rely on to keep injuries at bay while staying Hollywood ready involves nothing more than walking on a treadmill. The workout, Zocchi explains, revolves around zone 2 training.

Zone 2 training builds your aerobic base, your ability to use oxygen to generate energy when exercising. "It's like the lowest base of a pyramid. The bigger and better that base, the more every zone on top of it improves," says Zocchi.

The easiest way to know that you're in or around zone 2 is that you should be able to hold a conversation. "You should feel like you're working but not be so out of breath that you can't talk," says Zocchi. Here's how the workout breaks down.

How to do Chris Hemsworth's zone 2 treadmill workout

• Set a treadmill to a manageable incline. Zocchi tends to start off at a steep 10% incline and build to 15% but he stresses that it's important to work within your ability.
• Gradually increase the speed to a pace that's manageable but challenging. Zocchi tends to land at around 4-5km/h. Use the conversation test to find the pace that's right for you—you shouldn't be so out of breath that you can't hold a conversation at this pace.
• Now use the treadmill's heart rate sensors—or a wearable like an Apple Watch or Fitbit—to track your pulse. "I'll check my heart rate every couple of minutes. If it's going too low or high, I'll adjust the incline to stay in zone 2."
• Aim for around 30 minutes to build that zone 2 cardio base. Make a note of your incline and pace and try to nudge it up fractionally next time you repeat the session.

Centr Treadmills

Centr recently added treadmills to it's offering of home gym equipment, here's a look at three models.