Why athletes are moving from occasional altitude camps to year-round maintenance

For decades, altitude training was treated as a seasonal intervention.

An athlete would travel to the mountains—or sleep in a simulated-altitude environment—for several weeks before a major competition. The goal was to accumulate enough hypoxic exposure to stimulate adaptation, return to sea level and race while the benefits were still present.

That model can work. But it has an obvious limitation: once the altitude exposure stops, the stimulus stops too.

The next evolution in altitude use is therefore not simply a harder camp or a higher setting. It is maintenance—using a smaller, strategically timed hypoxic dose to help retain the adaptation already built.

The traditional model: build, race, lose, repeat

One of the most valuable adaptations to altitude is an increase in total haemoglobin mass. Haemoglobin carries oxygen in the blood, so increasing the total amount available can improve the body's capacity to transport oxygen to working muscle.

A meta-analysis of 17 altitude studies estimated that haemoglobin mass increased by approximately 1.1% for every 100 hours of altitude exposure. After athletes returned to sea level, haemoglobin mass remained around 3.3% above baseline for up to 20 days—but the longer-term picture was less certain and responses varied considerably between athletes.

That helps explain the classic altitude-camp strategy: accumulate a large dose, return to sea level and try to time the performance window.

But it also reveals the weakness of the approach. An altitude adaptation is not a permanent asset. Like strength, heat acclimation or aerobic fitness, it is a response to a repeated physiological signal. Remove that signal for long enough and at least part of the adaptation is likely to recede.

The new model: build, then maintain

A 2024 study in endurance athletes directly tested whether ongoing hypoxic exposure could slow this decline.

Following a 27-day hypoxic training camp, one group returned to normal sea-level training. Another group completed two hours of resting hypoxic exposure plus one hour of training in hypoxia every third day for a month.

Thirty days after camp, haemoglobin mass in the maintenance group remained 4.2% above its pre-camp level. In the group that received no further hypoxia, the remaining increase was 1.9%.

The important idea is not that every athlete should copy that exact protocol. The study combined hypoxic rest and hypoxic training; it was not a trial of overnight altitude sleeping. What it demonstrated is the broader principle: a smaller ongoing hypoxic stimulus can help preserve more of an adaptation than stopping altitude exposure completely.

That changes altitude from a one-off pre-race intervention into something that can be periodised across an entire year.

Why sleeping at altitude changes what is practical

Traditional altitude camps demand travel, time away from home and changes to an athlete's normal training environment. They can be highly effective, but they are difficult to repeat continuously.

Simulated-altitude sleeping makes a maintenance model far more practical. It allows an athlete to receive hypoxic exposure at home, usually without adding another training session or forcing high-quality workouts to be completed in reduced oxygen.

In other words, the athlete can still train with the power, pace and technical quality available at sea level, while using selected nights at simulated altitude to provide an additional hypoxic signal.

This does not mean sleeping as high as possible, every night of the year. More is not automatically better. Altitude is a training stress, and its effect depends on the dose, the athlete's response, iron availability, health, sleep quality and the rest of the training load.

The value of a home system is control: altitude can be increased during a focused build, reduced during recovery and reintroduced as a maintenance dose when appropriate. Athletes can use a dedicated sleep system or convert an existing space with an altitude bedroom system.

What year-round altitude periodisation can look like

A modern altitude programme can be viewed in four stages:

1. Build: Accumulate a meaningful block of consistent exposure over several weeks.

2. Consolidate: Continue exposure as the athlete returns to normal training, rather than ending it abruptly.

3. Maintain: Use a smaller, repeatable dose during the competitive or off-season period to help reduce the loss of adaptation.

4. Rebuild: Increase the dose again before an important competition or training phase, based on the athlete's response and goals.

The off-season does not need to become another full altitude camp. Its purpose is still recovery and preparation. Maintenance simply aims to prevent the athlete from returning all the way to their previous baseline before the next build begins.

There is not yet one scientifically established overnight maintenance prescription that suits every athlete. The appropriate altitude, number of nights and weekly hours should be individualised and adjusted using objective and subjective feedback.

Measure the right things

The phrase “keeping blood values high” needs some care. Higher is not always better, and a standard haemoglobin concentration can change with hydration and plasma-volume shifts even when the body's total oxygen-carrying capacity has not changed.

Where available, total haemoglobin mass is the more direct performance-relevant measurement. A complete monitoring picture may also include clinician-directed blood testing—such as haemoglobin, haematocrit, ferritin, transferrin saturation and reticulocytes—alongside overnight oxygen saturation, resting heart rate, sleep quality, recovery and performance data.

This is where tracking altitude adaptation with Oxygen Coach becomes useful. Oxygen Coach brings natural and simulated altitude exposure together with overnight SpO₂, heart rate, HRV, sleep, training and blood-marker checkpoints. It helps athletes and coaches see how the individual is responding, estimate what may be retained after an altitude block and decide whether the next step should be to progress, maintain or reduce the dose.

Those measures help answer the questions that matter:

• Did the athlete respond to the original altitude block?

• How quickly is that response declining?

• What is the smallest dose that appears to maintain it?

• Is altitude supporting the programme, or adding too much stress?

Individual variation is real. Even when haemoglobin mass increases, race performance is not guaranteed; a 2024 study in high-performance swimmers found an increase in haemoglobin mass after altitude without a corresponding improvement in competition performance. Altitude works within the wider training system—not outside it.

From a temporary peak to a higher baseline

The old altitude model was built around a temporary peak: go away, build the adaptation, race and allow it to fade.

The maintenance model asks a more useful question: once an athlete has invested in building an altitude adaptation, how much exposure is required to retain more of it?

For endurance athletes, that could mean starting each new training phase from a stronger physiological position instead of repeatedly rebuilding from zero. It may also allow altitude to sit alongside strength, nutrition, sleep and recovery as a managed part of the annual programme rather than a single seasonal event.

Altitude camps will remain important. The change is that the camp no longer has to be the end of the strategy.

With controllable simulated-altitude sleeping, athletes can build, maintain and rebuild the stimulus around real life—without relocating to the mountains each time.

Altitude is no longer just somewhere an athlete goes. It is a training input that can be managed throughout the year.

Build the exposure. Measure the response.

Box Altitude provides the controlled altitude environment. Oxygen Coach connects exposure with sleep, recovery, training and blood markers—helping athletes track the adaptation rather than simply count the hours.

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References

1. Gore CJ, et al. Altitude training and haemoglobin mass from the optimised carbon monoxide rebreathing method determined by a meta-analysis. British Journal of Sports Medicine, 2013. PubMed

2. Peltonen JE, et al. Combined intermittent hypoxic exposure at rest and continuous hypoxic training can maintain elevated hemoglobin mass after a hypoxic camp. Journal of Applied Physiology, 2024. PubMed

3. Astridge DJ, et al. Haemoglobin mass responses and performance outcomes among high-performance swimmers following a 3-week live-high, train-high camp at 2320 m. European Journal of Applied Physiology, 2024. PubMed

This article is for general information only. Altitude exposure should be individualised, and athletes with medical conditions, abnormal blood results or concerns about iron status should consult an appropriately qualified clinician or sports physician.

 

Oxygen Coach: https://oxygencoach.ai/