What about training at elevation or
working out on the treadmill with one of
those Predator–style hypoxic masks? After
all, don’t all the top endurance athletes
run high up in the mountains? Wouldn’t
just living at altitude boost your VO2 max
and reduce your fitness age?
Nope again. The science on hypoxic
masks is thin. “Even though there are some
believers out there, I know that world-class
endurance athletes in, for instance, some
cross-country skiing do not use them,”
Wisløff says. While some world-class
endurance athletes travel to high altitudes
to train, the effect on performance is tiny.
If you’re the third-best 800m runner in
the world and you want to become the
best 800m runner in the world, then by all
means move to La Paz, Bolivia (altitude:
nearly 3,700m). But if you’re something
other than an Olympian, you’re going to
make the same gains if you do all your
interval training in Sydney or Melbourne.
YOUR HEART IS
MORE TRAINABLE
AND ADAPTABLE
THAN YOU
IMAGINED.me with “good cross-country skiing
conditions here now!”
Wisløff views the 4x4 training as a key
fitness intervention, something everyone
should and can integrate into the fitness
routine that they’re already doing.
“When I stopped playing soccer,
and I got kids, I became more inactive.
But when I started to become active
again, I would do interval training two
times one week, then three times the next,
and that’s a really good way to improve
fitness quickly,” Wisløff says. “It’s an
oxygen cure.”Stay Young Tip No. 6:Choose Your
Devices Wisely
By now you’ve probably realised that
many popular device-based approaches
to improving fitness just don’t pass muster
when you’re trying to reduce fitness age.
Walk 10,000 steps per day? Why? Your
heart rate is never going to get anywhere
close to a range where you can lower your
fitness age. Exercise for 150 minutes per
week? Sure, that sounds good. But what’s
your real output going to be? Heart rate is
a better measure, but Wisløff realised that
on its own, it didn’t mean a whole lot.
“I’ve been struggling and trying to find
how we can translate changes in heart rate
into a meaningful index that actually tells
me if I’m doing enough exercise per week
to be protected against lifestyle-related
diseases,” Wisløff says.
What he came up with was a new metric
called Personalized Activity Intelligence
(PAI), which is basically Wisløff ’s
fitness-age calculator in weekly-exercise-
plan app form. Your PAI goal is to maintain
a weekly score of more than 100. That’s the
point at which Wisløff ’s studies show that
a man’s risk of cardiovascular disease gets
reduced by 17%. (After that point, you’ll
get fitter, but your risk of cardiovascular
disease won’t significantly decrease.)
A couple of exercises per week that in
total raise your heart rate so you breathe
heavily for about 40 minutes will give you
100 PAI. You can get it also by exercising
at moderate intensity for a few hours.
The higher the intensity the more PAI you
earn. It absolutely can be achieved by low
to moderate intensity as well.
Daily workouts are not required. “The
data is so clear. You don’t need to exercise
every day; you just need to have 100 PAI
per week,” Wisløff says. So super-intense
workouts like 4x4 interval training can
easily be spaced out with rest days or days
of low-intensity workouts, and you’ll still
be bulletproofing your body and health.
By that point, you might even be able to
compete with Wisløff. His fitness age, he
told me, is below 20.■STAY YOUNG TIP NO. 5:
SAVE TIME FOR CROSS-TRAINING
You might expect that Wisløff would
advise those looking to reduce their fitness
age to do nothing but lung-busting sessions
of 4x4 interval training. But he knows
personally that such a course would be
counterproductive.
“I can’t just do 4x4,” he says. “I think
it’s totally boring to do just that.”
In his fitness-age-reducing fitness
program, Wisløff reserves days for fun
runs and 60-minute activities like five-
a-side soccer, and he practices what
he preaches. He performs 4x4 interval
training only a couple of times per week.
(One session is always a lab-wide workout
in which he leads his 60-person staff
in exercises.) The rest of the time, he
works out like an outdoorsy and not
especially fitness-obsessed man. He
plays a weekly game of soccer. He kayaks.
In November, he ended one email to84 MEN’S FITNESS APRIL 2017