I guess vrabel isn’t a mountaineer. I guess the he hasn’t heard about acclimatization. They won’t be able to breath come the 4 th q.
Just researched some things here, interesting timelines.
Short answer: altitude acclimation is real, measurable, and it does affect NFL performance, but how much depends on position, conditioning, and game flow.
Let’s break it down cleanly.
🏔️ What changes physiologically at Denver altitude?
Denver sits at ~5,280 feet. At that altitude:
Oxygen pressure is ~17% lower
Less oxygen enters the bloodstream with each breath
Your muscles fatigue faster during high-intensity bursts
This isn’t about lungs being “weak” — it’s about oxygen delivery to working muscles.
🧪 What science says about acclimation
Short-term exposure (0–24 hours)
No real physiological adaptation yet
Oxygen saturation drops
Heart rate and breathing rate increase to compensate
Athletes feel fine initially, then fatigue hits harder later
This is why teams sometimes arrive very late — to avoid prolonged exposure before game day.
Partial acclimation (3–7 days)
Slight improvements in oxygen utilization
Still not fully adapted
Many teams consider this the worst window — enough exposure to feel the effects, not enough to adapt
True acclimation (10–14+ days)
Increased red blood cell production
Improved oxygen delivery
Endurance improves meaningfully
⚠️ NFL teams almost never do this — too disruptive to schedules and recovery.
🏈 How lack of acclimation affects NFL performance (position by position)
Most affected
Defensive linemen & linebackers
Repeated explosive efforts
Short recovery windows
Fatigue shows up late in drives
📉 Result:
Slower pass rush in 2nd half
Missed tackles
Poor pursuit angles
Moderately affected
Receivers, DBs, RBs
Sprint-heavy but with rest between plays
Fatigue affects:
Route sharpness
Recovery speed
Late-game separation
📉 Result:
Drops
Slower breakouts
Defensive lapses late
Least affected
Quarterbacks
Minimal continuous exertion
Can manage breathing and pacing
📌 Altitude mostly affects QBs indirectly (OL fatigue, timing breakdowns).
⏱️ Where it shows up in a game
Altitude effects rarely show in Q1.
They show up:
Late Q2
Q4
Extended drives
No-huddle sequences
Long defensive series
That’s why Denver historically:
Plays better late
Defends home field well
Benefits from tempo changes
📊 What the data suggests (not myths)
Studies across soccer, rugby, and American football show:
VO₂ max decreases 5–10% at Denver altitude
Sprint recovery time increases
High-intensity repeat efforts suffer most
NFL-specific tracking has shown:
Visiting defenses rotate more
Higher snap-to-snap fatigue late
Conditioning advantage favors the home team
❓ So is acclimation “worth it” for NFL teams?
Here’s the honest, evidence-based take:
Two viable strategies:
Arrive very late (≤24 hours before kickoff)
✔ Avoid cumulative fatigue
✔ Accept short-term oxygen deficit
Arrive very early (10–14 days)
✔ True adaptation
❌ Unrealistic for NFL logistics
🚫 The middle option (3–5 days) is generally considered the worst scientifically.
🧠 Bottom line (plain English)
Altitude absolutely matters
Not acclimating hurts endurance, not skill
Effects show late in the game, not early
Defensive players suffer most
Late arrival is a legitimate, science-backed strategy
No approach fully negates altitude — it’s about minimizing damage
If you want, I can:
Compare Patriots vs Broncos historical altitude games
Break down which coaching staffs manage altitude best
Explain why Denver’s home advantage is smaller today than 10 years ago
Just say the word.
