You’re a 35-year-old desk jockey with the heart of a 60-something couch potato? Join the club, Jack.

But there’s hope for you yet: Ulrik Wisløff, Ph.D., a professor of physiology at the Norwegian University of Science and Technology, has created a seven-week program that primes your heart for a better "fitness age"—and burns plenty of fat—in just minutes of sweat. What's fitness age? Wisløff created the concept to translate how someone's VO2 max (a measure of how efficiently their body can use the oxygen they breathe) into an overall measure of health—and therefore a measure of their expected lifespan.

The best part? You can do any kind of exercise you want. Swimming, cycling, rowing, and running are popular, but anything will work, as long as you’re pushing your heart to the limit. With just two of these 4x4 workouts a week, Wisløff’s lab has made progress with everyone from untrained shlubs to elite athletes.

How it works

This workout routine is built around Wisløff’s lab-tested “4x4 interval training” workout: four minutes of high-intensity exercise, followed by three minutes of active recovery, repeated four times. Some of the days are "kick starts," which are shorter bouts of just 4 minutes of high-intensity exercise. Wisløff also intermixes a few cross-training days into the workout, so you're building some muscle (and fighting boredom) in the routine.

For more on Wisløff's research on the 4x4 workout method, check out this video on his lab's website. (It's in English.)

Directions

The core concept of the 4x4 plan is the interval workout. In the work phase of the interval, you'll blast your heart to 85–95% of its maximum rate—not quite all-out effort, but intense enough that you’ll be able to say only a few four-letter words by the end. Then you’ll downshift to a three-minute active-recovery phase at 70% capacity—still moving, but moderately enough to catch your breath and scrub lactic acid from your muscles. That's one round.

A few more important notes:

  • Don’t worry about going 100% in the last round—Wisløff says it doesn’t hurt, but the benefit is practically negligible compared to 90% effort, and it usually just discourages athletes as the program goes on.
  • A simple rule of thumb for calculating your maximum heart rate is subtracting your age from 220—so if you’re 30, then your ticker probably tops out at 190 beats per minute.
  • Remember: Always warm up 10 minutes before each workout, and cool down at least 5 minutes before the workout. Don't start cold!

Ulrik Wisløff's 7-day add-years-to-your-life workout plan

WEEK 1

Monday: 4-min. “kick start”
 
Wednesday:
Endurance: 20-min steady-state cardio (no stopping!)
Core strength: 10 pushups, 15 air squats, 10 jump squats

Friday: 2 x 4 interval workout

  • 4 min. intense effort
  • 3 min. relaxed
  • 4 min. intense effort
  • 3 min. relaxed

WEEK 2

Monday: 4-min. kick start

Wednesday: 3 x 4 interval workout

Friday: Core circuit
Do the following circuit three times, resting 30 sec. between each set of exercises and one min. between each circuit.

  1. 5-10 split squats. (Take a big step forward with one foot, so your knee barely touches the ground, and then spring back to the starting position. Repeat with the opposite leg. That’s one rep.)
  2. 5-10 squat jumps. Make sure to get as low as you can in the squat—no half-reps!
  3. 5-10 pushups

WEEK 3

Monday: 3 x 4-min. interval workout

Wednesday: 60-min. cardio pick ‘em
Grab your buddy (or your dog) and move your ass for an hour—bonus points if it’s something you don’t normally do. Have fun.
 
Friday: 4-min. work

WEEK 4

Monday: 4 x 4 interval workout

Wednesday: 4 x 4 interval workout

Friday:
Endurance: 4-min. kick-start
Core strength:

  1. 10 squats
  2. 7 split squats on each foot
  3. 5 squat jumps
  4. 1 set max effort pushups
  5. 7 squats
  6. 5 split squats on each foot.
  7. 5 squat jumps
  8. 1 set max effort pushups

WEEK 5

Monday: 4-min. kick-start

Wednesday:
Endurance: 20-minute steady-state cardio (no stopping!)
Core strength:

  1. 10 pushups
  2. 15 squats
  3. 10 squat jumps
  4. 15 squats
  5. 10 squat jumps
  6. 10 pushups
  7. 15 squats
  8. 10 squats jumps
  9. 10 pushups

Friday: 60-min. cardio pick ‘em

WEEK 6

Monday: 4 x 4-min. intervals

Tuesday:
Endurance: 20-min. cardio
Core strength: 10 pushups, 15 squats, 10 squat jumps

Thursday: 4 x 4-min. intervals
 
Friday:
Endurance: 20-min. steady-state cardio
Core circuit: Do the following three times without stopping:

  • 10 pushups
  • 15 squats
  • 10 squat jumps

WEEK 7

Monday: 4 x 4-min. interval workout

Wednesday: 60-min. cardio pick ‘em

Thursday
1.    1 set max-effort situps
2.    30-minute walk or jog at a pace where you're not too winded to keep up a conversation.
3.    1 set max-effort situps

Ready for the next seven weeks of workouts? Check out the full routine on Wisløff's website here.