O Turn back your body clock
Like most fit guys, you’re probably addicted to numbers.
Chances are you know your max bench and squat, and you might have a pretty good fix on your body mass index, too. If you’re super hardcore, you might even know your basal metabolic rate (for the uninitiated, that’s the amount of energy your body churns through when you’re at rest). And no doubt if you’re an endurance guy, you can list your PRs in everything from the 5K to a marathon. But before you get too confident in the story that these numbers tell, especially as they pertain to your long-term health, Ulrik Wisløff, PhD, a professor of physiology at the Norwegian University of Science and Technology, has an important question for you: What is your fitness age? Wait, you don’t know? Well, according to Wisløff, a 49-year-old former semipro soccer player who is also one of the world’s top exercise scientists, that’s deeply unfortunate. Because your fitness age — even more than your real age — is the key to providing confirmation of your physical prowess or exposing a gaping void at the centre of what you thought was a solid training program. What’s more: Paying special attention to your fitness age, which you can maintain with a very targeted HIIT training regimen, might just save your life years down the road.
Fitness age, which Wisløff introduced to the world in a 2014 study, is rooted in your body’s level of cardiorespiratory fitness (CRF) — its ability to disperse and consume oxygen. In fact, having great CRF — not to be confused with cardiovascular fitness, which refers only to the heart and blood but not the body’s breathing apparatus — is such an important factor to your longevity
