071 - Train Hot to Perform High: Heat Acclimation for Altitude Readiness
In tactical operations and elite athletics, the environment can make or break performance. High altitudes reduce oxygen availability, compromise physical output, and increase the risk of illness. Layer in heat—whether from gear, weather, or metabolic demand, and you’ve got a dual threat to operational readiness.
This article breaks down how heat acclimation (HA) can serve as a powerful cross-adaptive strategy to protect performance in hypoxic conditions, without sacrificing training time or requiring mountains to do it.
What They Found:
This review synthesized multiple studies showing that heat acclimation (HA)—repeated exercise in hot conditions—induces physiological and cellular changes that carry over to improve tolerance and performance at altitude. Key findings include:
HA preserved or improved VO₂max during hypoxic exposure (2,400–4,350m).
Heat stress increased heat shock protein (HSP72) expression, enhancing cellular protection and red blood cell production.
Submaximal performance improved in most cases (lower HR, RPE, thermal strain).
Protocols ranged from 3 to 12 days, using moderate intensities (35–55% VO₂max) in hot, controlled environments (38–40°C).
Benefits were noted even from a single heat session, especially in aerobically fit individuals.
What This Means:
If you’re prepping for operations or competitions at altitude but can’t access elevation, HA may be the next best thing—or in some cases, the smarter choice. For tactical populations: firefighters, military personnel, or operators training in flat terrain, training in heat could pre-load the body’s defenses against hypoxia, fatigue, and heat illness. And unlike traditional altitude camps, HA is cheap, fast, and scalable.
Tactical Implications:
Prep in the Heat Before High Ground: If a mission or event takes place at elevation, 5–10 days of HA can preserve aerobic capacity and blunt the effects of reduced oxygen.
Use Heat When Altitude Isn’t Available: Can’t get to 10,000 feet? Turn up the temperature instead. Use layers, dark clothing, or midday sun to simulate stress.
Individualize by Fitness Level: Less-fit individuals may require longer, lower-intensity protocols. More-fit individuals benefit from shorter, higher-intensity sessions.
Monitor Strain, Not Just Sweat: Use RPE, heart rate, and thermal symptoms—not just performance—to track acclimation progress. Watch for red flags of heat illness.
Questions To Consider:
Are your team’s environmental stressors being trained or just tolerated?
How might heat acclimation protect your operators when real altitude exposure isn't an option?
Is your training calendar prioritizing environment-specific preparation, or just general capacity?
Could you simulate deployment conditions better with controlled heat training?
What safeguards and systems do you have in place for identifying heat stress and ensuring recovery?
Albert, Beverly1; Miller, Michael G.2. Preserving Athletic Performance at Altitude with Heat Acclimation: A Cross-Adaptive Approach. Strength and Conditioning Journal 47(3):p 279-286, June 2025. | DOI: 10.1519/SSC.0000000000000869