Weekly VO₂ max intervals
One session/week of 4×4 minute intervals; raises VO₂ max, strongly correlated with longevity.
Why
VO₂ max (maximum oxygen uptake) is among the strongest single physiological correlates of all-cause mortality. The Norwegian 4×4 protocol (4 min hard, 3 min easy, ×4) is the most-studied intervention to raise it. One session per week is enough for meaningful improvement; more risks under-recovery.
The program
- 1
Warm up 10 minutes at easy pace.
- 2
4 minutes at ~90% max HR: very hard, can speak only short phrases.
- 3
3 minutes easy recovery.
- 4
Repeat the 4-minute hard / 3-minute easy block 4 times total.
- 5
Cool down 5-10 minutes.
- 6
Once per week; more risks under-recovery.
Practical
Cadence
Once per week
What you'll need
A solid Zone-2 base (12+ weeks of regular cardio)
Ideal for
People with a Zone 2 base who want to push their cardiovascular ceiling.
Markers this may influence
Evidence
Helgerud 2007 Med Sci Sports Exerc RCT (n=40 healthy men): 8 weeks of 4×4-minute intervals raised VO₂max by ~10%, significantly more than moderate continuous training matched for total volume. VO₂max is among the strongest single physiological correlates of all-cause mortality, with effects measurable within 6–8 weeks.