Altitude training has long been used by elite endurance athletes to enhance performance. By exposing the body to lower oxygen availability, it can trigger a series of physiological adaptations that may translate into improved sea-level performance. For cyclists aiming to maximise aerobic capacity and endurance, altitude training represents a potentially valuable, though complex, tool in their training arsenal.

What Altitude Does to the Body

To understand altitude training, it is essential to clarify a common misconception: although the concentration of oxygen in the air remains constant at around 20.9 percent, the barometric pressure decreases as altitude increases. This results in a lower partial pressure of oxygen (PO₂), the component of atmospheric pressure attributable to oxygen.

At sea level, the PO₂ is approximately 159 mmHg, but at 2500 metres, it falls to around 115 mmHg. This reduction limits the pressure gradient driving oxygen from the lungs into the bloodstream, leading to less oxygen diffusing into the blood with each breath. Although the lungs are still inhaling air with the same proportion of oxygen, the reduced pressure at altitude makes oxygen uptake less efficient, causing a condition known as hypoxaemia.

This drop in oxygen availability is what stimulates the body to adapt. Over time, mechanisms such as increased ventilation, enhanced production of erythropoietin (EPO), and ultimately a rise in red blood cell mass help compensate for this challenge, improving the body’s ability to transport and use oxygen during exercise. These changes form the physiological foundation for altitude training strategies used by cyclists and other endurance athletes.

The Science Behind Altitude Training

At altitudes above approximately 1800 metres, the reduced PO₂ triggers a cascade of physiological responses. One of the primary adaptations is the increased production of EPO by the kidneys primarily, which stimulates red blood cell production. This improves the oxygen-carrying capacity of the blood, potentially enhancing endurance performance upon return to sea level.

Numerous studies support these effects. Levine and Stray-Gundersen’s seminal work on the live high, train low (LHTL) model found that athletes who slept at altitude but trained at lower elevations experienced improved sea-level performance, due to a combination of haematological and muscular adaptations.

Altitude Training Methods: LHTL, LHTH & IHE

There are several approaches to altitude training, each with different benefits and practical considerations:

Live High, Train Low (LHTL): Athletes live or sleep at moderate altitude (usually 2000–2500 metres) to stimulate EPO production, while descending to lower altitudes to complete high-quality training sessions. This method aims to maximise adaptation while avoiding the performance compromises associated with training in hypoxic conditions.

Live High, Train High (LHTH): Both living and training occur at altitude. While this can stimulate adaptations, training intensity may be compromised due to reduced oxygen availability.

Intermittent Hypoxic Exposure (IHE): Athletes use simulated altitude (such as altitude tents) for a few hours daily. Though convenient, the benefits may be smaller unless exposure is consistent and prolonged.

Altitude Tents: These simulate hypoxic conditions by reducing the oxygen concentration in the air. They allow athletes to incorporate LHTL principles without relocating. However, they require a disciplined routine and may affect sleep quality unless carefully managed.

Performance Benefits of Altitude Training in Cycling

When implemented correctly, altitude training may offer several benefits:

• Increased Red Blood Cell Mass: Leading to greater oxygen delivery to muscles

• Improved VO₂max: Especially beneficial in aerobic sports such as cycling

• Enhanced Efficiency: Mitochondrial and muscular adaptations may improve endurance

• Mental Toughness: Training in challenging environments can build resilience

These benefits are most pronounced when exposure lasts for at least 2 to 3 weeks, with some studies suggesting that 3 to 4 weeks of consistent altitude exposure is optimal for meaningful haematological gains. Performance benefits tend to persist for 2 to 3 weeks post-exposure before gradually declining, though this can vary depending on the individual and the training load maintained afterward.

Altitude Training Risks and Adaptation Factors

Despite its potential, altitude training is not universally effective. Not all athletes respond equally. Roughly 20 to 25 percent of individuals are considered non-responders, failing to show significant haematological adaptation.

Several factors influence adaptation:

• Altitude Level: Too low and adaptation is minimal; too high may impair recovery

• Duration of Exposure: Short stays offer limited benefits

• Genetics: Some individuals naturally have higher EPO responsiveness

• Nutrition and Recovery: Poor fuelling or inadequate sleep can blunt adaptation

Another important consideration is that altitude often increases carbohydrate utilisation. This is due to the body favouring glucose over fat when oxygen is limited. Cyclists should increase carbohydrate intake, particularly around training sessions, to support performance and recovery. Consuming an additional 10 to 15 percent more carbohydrates may be necessary.

How to Do Altitude Training Safely and Effectively

• Support Sleep Quality: Many athletes report disturbed sleep at altitude. Using tart cherry juice, which contains natural melatonin, may help improve sleep onset and quality. Creating a cool, dark, and quiet environment also supports better sleep.

• Stay Hydrated: Dehydration occurs more easily at altitude due to increased ventilation and fluid loss. Monitor urine colour and consider electrolyte supplementation.

• Gradual Acclimatisation: If travelling to altitude, allow a few days of reduced-intensity training to adapt before resuming harder efforts.

• Supplement Wisely: Iron is essential for red blood cell production. Ensure iron levels are sufficient before beginning altitude training, especially in female athletes.

• Monitor Training Load: Training load should be monitored through tools such as Vekta, monitoring metrics like heart rate variability and resting heart rate, and adjusted accordingly during the early stages of exposure.

• Use Altitude Tents with Care: Start with short durations (4 to 6 hours), gradually increasing to overnight exposure. Aim for 12 to 16 hours per day to mimic real altitude exposure.

Altitude Alternatives: Heat Training

Interestingly, some studies have found that heat training can induce adaptations similar to altitude training, such as increased plasma volume and improved thermoregulation. However, these effects are not equivalent to the erythropoietic benefits of altitude. Heat acclimation may be a practical tool when altitude is not accessible but should be seen as a complement rather than a replacement.

Conclusion

Altitude training can offer significant performance benefits for cyclists, particularly when using the live high, train low model. However, success depends on careful planning, individual response, and supporting factors such as nutrition, sleep, and recovery. With proper implementation, it can be a powerful method to improve endurance, enhance oxygen delivery, and boost race-day performance.

For those unable to train at real altitude, tools like altitude tents or heat training can provide partial adaptations and expand the options available for performance enhancement.

Work with Andy

If you want to learn more about Andy’s coaching approach or explore working with him directly, visit ATP Performance to see how he helps athletes train with purpose, adapt with precision, and perform at their best.

References

Levine, B. D., & Stray-Gundersen, J. (1997). Living high-training low: Effect of moderate-altitude acclimatization with low-altitude training on performance. Journal of Applied Physiology, 83(1), 102–112.

Chapman, R. F., Karlsen, T., Resaland, G. K., Ge, R. L., Harber, M. P., Witkowski, S., et al. (2014). Defining the "dose" of altitude training: How high to live for optimal sea-level performance enhancement. Journal of Applied Physiology, 116(6), 595–603.

Gore, C. J., Hahn, A. G., Burge, C. M., & Telford, R. D. (2001). VO₂max and haemoglobin mass of trained athletes during high intensity training. International Journal of Sports Medicine, 22(7), 498–504.

Burtscher, M., Krüsmann, P., Hochstrasser, A., & Faulhaber, M. (2018). Nutrition and altitude training. Sports Science Exchange, 29(180), 1–6.

Lorenzo, S., Halliwill, J. R., Sawka, M. N., & Minson, C. T. (2010). Heat acclimation improves exercise performance. Journal of Applied Physiology, 109(4), 1140–1147.