Altitude training for cyclists has been a cornerstone of professional preparation for decades. The principle is simple: expose your body to reduced oxygen, and it responds by producing more red blood cells. More red blood cells means more oxygen delivery to muscles. More oxygen means more power.
But the reality is considerably more complicated than the marketing suggests.
The Science: What Actually Happens at Altitude
At 2,500 metres, the air contains roughly 26% less oxygen than at sea level. Your body responds with several adaptations:
- Increased EPO production — your kidneys release erythropoietin, stimulating red blood cell production
- Higher haemoglobin mass — more oxygen-carrying capacity in your blood
- Improved oxygen extraction — muscles become more efficient at using available oxygen
- Increased capillary density — better blood supply to working muscles
These adaptations take time. You need a minimum of 2-3 weeks at altitude to see meaningful changes in blood markers.
Live High, Train Low
This is the gold standard protocol, developed by Dr Ben Levine and Dr Jim Stray-Gundersen and used by virtually every WorldTour team. The concept: sleep and rest at altitude (2,000-2,500m) to get the haematological stimulus, but descend to lower elevation (below 1,500m) for hard training sessions.
Why? Because at altitude, your maximum power output drops. You simply cannot produce the same training stimulus at 2,500m as you can at sea level. Your VO2max intervals suffer. Your top-end sessions are compromised.
The protocol:
- Sleep at 2,000-2,500m for 12+ hours per day
- Train at below 1,500m for all intensity sessions
- Zone 2 rides can be done at altitude
- Duration: minimum 3 weeks, ideally 4
- Allow 2-3 weeks post-camp for peak performance
Altitude Tents and Simulators
For those of us without access to mountain ranges, altitude tents simulate the reduced oxygen environment. They're expensive (£3,000-5,000) and the compliance requirements are demanding — you need 10-12 hours per day for several weeks.
The research is mixed. Some studies show meaningful haemoglobin increases, others show negligible changes. The key variable seems to be total hours of exposure. Sporadic use doesn't work.
The Amateur Cyclist Reality Check
Here's the honest take. For most amateur cyclists, the marginal gains from altitude training are dwarfed by improvements available through:
- Better periodisation
- Consistent base training
- Proper nutrition and recovery
- Simply riding more
If you're training 8-12 hours a week and haven't optimised your training structure, altitude training is putting the roof on before you've built the walls.
Racing at Altitude
If you're heading to an event at altitude — Alpine sportives, Colorado races — acclimatisation matters. Arrive at least 3-4 days early, or arrive the day before. The worst timing is 1-2 days before, when you feel the altitude effect but haven't begun adapting.
Pacing at Altitude
Your FTP drops roughly 5% per 1,000m of elevation above your home altitude. A 300W FTP rider at sea level is effectively a 270W rider at 2,000m. Pace accordingly.
When Altitude Training Makes Sense
- You've already optimised training, nutrition, and recovery
- You have access to genuine live-high-train-low logistics
- You can commit to 3-4 weeks of the protocol
- You have a specific goal event 2-3 weeks after returning to sea level
Key Takeaways
- Live high (2,000-2,500m), train low (below 1,500m) is the proven protocol
- Minimum 3 weeks of exposure needed for meaningful blood adaptations
- Peak performance occurs 2-3 weeks after returning to sea level
- Altitude tents require 10-12 hours daily to be effective — compliance is the bottleneck
- FTP drops roughly 5% per 1,000m of altitude
- For most amateurs, optimising training structure and nutrition yields bigger returns
- Use the FTP Zone Calculator to adjust your power zones for altitude — drop targets by 5% per 1,000m
- If racing at altitude, arrive 3-4 days early or the day before — not 1-2 days before
