VO2max is the maximum rate at which your body can consume oxygen during exercise. Measured in ml/kg/min. It represents the absolute ceiling of your aerobic performance, and if that ceiling is low, your FTP can only go so high.
Why cyclists should care
Your FTP typically sits at 75-95% of the power output associated with VO2max. Think of VO2max as the size of your engine and FTP as the percentage of that engine you can sustain. A bigger engine means more room to grow.
If you've been doing threshold work for months and your FTP won't budge, your VO2max is probably the bottleneck.
Where do you stack up?
- Sedentary: 30-40 ml/kg/min
- Recreational cyclist: 40-50
- Trained cyclist: 50-60
- Competitive amateur: 60-70
- Elite/Pro: 70-85+
Genetics play a big role. Research suggests 50-80% of VO2max is genetically determined. But the trainable 15-20% is still huge. That's the difference between getting dropped on every climb and hanging with the group.
The workouts that move the needle
VO2max responds to intervals that force your cardiovascular system to operate near its maximum for sustained periods. That means efforts at 106-120% of FTP lasting 3-8 minutes.
5x4 min (the classic)
4 minutes at 110-115% FTP, 4 minutes recovery, 5 times. You accumulate 20 minutes near max. By interval 3, you'll be questioning your life choices. By interval 5, you'll want to quit cycling. Do it anyway.
3x8 min
8 minutes at 106-110% FTP, 5-6 minutes recovery. Longer at slightly lower intensity. These build both VO2max and the mental ability to sustain hard efforts. They're uniquely awful.
30/30s (Billat intervals)
30 seconds at 120% FTP, 30 seconds at 50% FTP, 12-20 times. Deceptively hard. The short recovery means your heart rate never fully drops, so you spend most of the set near VO2max despite the alternating structure.
How often
1-2 sessions per week during a build or peak phase. VO2max intervals are the most fatiguing type of aerobic training. Never on back-to-back days. Allow at least 48 hours before the next hard session.
When improvement slows
VO2max gains come fastest in the first 6-12 months of structured training. After 2-3 years, you're approaching your genetic ceiling and gains slow dramatically. At that point, further performance comes from improving FTP as a percentage of VO2max (threshold work) and from efficiency (accumulated years of riding).
This doesn't mean you stop doing VO2max work. It maintains your ceiling. But the pace of improvement is different in year 5 than year 1.
Quick rule of thumb
If your FTP is below 75% of VO2max power, your limiter is threshold fitness. If it's above 85%, your limiter is VO2max. Most recreational cyclists are limited by both, and a balanced plan addresses both.