When Should You Race After Altitude Training?

You have finished an altitude block and your race is approaching. Should you compete straight away, wait ten days, or allow several weeks?

There is no single best day to race after altitude. A dip around day ten appears in coaching advice, but research has not established it as an inevitable response. [1] The type of altitude exposure and how training is tapered may both matter. [1,2]

This article concerns racing at sea level or low altitude after an altitude block. Preparing for a race held at altitude is a different question.

Where the idea of a day-ten dip comes from

In their 2014 review, Chapman and colleagues collected recommendations from experienced altitude coaches and applied sport scientists. Those recommendations varied. One suggested racing within the first 48 hours or after day ten, and avoiding days 3–9; another suggested days 3–7 or days 14–25, and avoiding days 8–13. The others favoured racing after roughly two or three weeks. [1]

The days 8–13 window includes the “lull around ten days” many athletes have heard about, although the first of those recommendations treated the days after day ten as a good time to race.

However, these were largely observations and coaching recommendations, rather than controlled trials proving a predictable dip. The review discussed several factors that could affect race timing, including breathing adjustments and the return to faster training speeds, but did not propose a mechanism that makes athletes perform worse on day ten. [1]

What the studies actually found

Some runners raced well within eight days

Sharma and colleagues followed eight elite runners through three to four weeks of living at a natural altitude of 2,100 metres, with training mostly at 2,100–2,700 metres. Training load was reduced substantially during the final week at altitude. [3]

Seven of the eight raced within eight days of returning to sea level, and all seven recorded lifetime personal bests. However, the overall performance improvement was not statistically significant, and the study had no sea-level control group. It cannot separate the effects of altitude, training, tapering and competition conditions. Results vary. [3]

This small observational study challenges the idea that everyone must wait several weeks before racing.

A triathlete study found later improvements

Saugy and colleagues studied 16 well-trained triathletes in a crossover comparison of natural and simulated altitude. Each athlete completed both types of 18-day camp, separated by a year. They lived at an actual or simulated 2,250 metres and trained at 1,100–1,200 metres. [4]

Running performance was tested over three kilometres before the camps and at one, seven and 21 days afterwards. In both conditions, times were significantly faster at day 21 than at baseline, with no significant difference between conditions at any test. Times were also faster on average at days one and seven after both camps, though this was statistically significant only after the natural-altitude camp. [4]

The study compared two forms of altitude exposure, without a normal-air training control. It also did not test performance on day ten or every day around it. It therefore supports a possible later racing window without proving a day-ten dip or identifying the exact best day. Results vary. [4]

Swimmers have also used longer gaps

A 2023 collective case study by González-Ravé and colleagues examined six international swimmers whose programmes included repeated natural-altitude camps. Their final return occurred 20–32 days before the main competition, most commonly 28 days. [5]

The swimmers recorded improved competition performances, but this was an observational account of a complete season programme. It did not randomly compare different return dates, so it cannot establish that waiting four weeks is better than racing earlier. Results vary. [5]

Does the same timing apply to sleeping at simulated altitude?

A mountain camp and overnight simulated altitude are different training arrangements.

At a mountain camp, an athlete may live and train at altitude. With a home sleep-high, train-low arrangement, daytime sessions can continue in normal air. Exposure hours, training conditions and travel demands can all differ.

The simulated-altitude condition in the Saugy study involved approximately 230 hours of exposure over 18 days (about 12.7 hours a day), with training at 1,100–1,200 metres. It was not a trial of eight hours each night at home while training at sea level. Its results do not establish when a home user should stop exposure before racing. [4]

Mujika, Sharma and Stellingwerff’s 2019 review places altitude within the wider training programme, emphasising periodisation and monitoring, and recognising individual response. [2] In our view, that approach is more useful than transferring a fixed mountain-camp calendar to every athlete.

How to plan your own race timing

A practical approach is to rehearse the timing before a lower-priority event, with your coach, rather than introduce a new schedule immediately before your main race.

Keep a record of the exposure, training load, taper, travel and subsequent sessions or races. Compare repeatable workouts under similar conditions. One flat session is not enough to establish a recurring post-altitude dip.

Use that record to decide whether an earlier or later race window suits your preparation. These are planning suggestions, not a study-validated formula.

Day ten is not automatically a bad day to race. The useful question is how you respond to a particular altitude block and taper. Current evidence supports an individual plan; it does not justify promising a single best race day for every athlete. [1]

References

1. Chapman RF, Laymon Stickford AS, Lundby C, Levine BD. Timing of return from altitude training for optimal sea level performance. Journal of Applied Physiology. 2014;116(7):837–843. doi:10.1152/japplphysiol.00663.2013. PMID:24336885. Narrative review distinguishing coaching recommendations from limited serial performance evidence.
2. Mujika I, Sharma AP, Stellingwerff T. Contemporary Periodization of Altitude Training for Elite Endurance Athletes: A Narrative Review. Sports Medicine. 2019;49(11):1651–1669. doi:10.1007/s40279-019-01165-y. PMID:31452130.
3. Sharma AP et al. Training Quantification and Periodization during Live High Train High at 2100 M in Elite Runners: An Observational Cohort Case Study. Journal of Sports Science and Medicine. 2018;17(4):607–616. Full study. PMID:30479529.
4. Saugy JJ et al. Same Performance Changes after Live High-Train Low in Normobaric vs. Hypobaric Hypoxia. Frontiers in Physiology. 2016;7:138. doi:10.3389/fphys.2016.00138. PMID:27148076. Crossover study extending the group’s earlier comparison; these publications should not be treated as wholly independent evidence.
5. González-Ravé JM, Castillo JA, González-Mohino F, Pyne DB. Periodization of altitude training: A collective case study of high-level swimmers. Frontiers in Physiology. 2023;14:1140077. doi:10.3389/fphys.2023.1140077. PMID:36891142.