103.THE BEST WAY TO COMBINE ALTITUDE AND HEAT TRAINING

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To date (September 2025), the two environmental stimuli that, if performed regularly for several weeks, are capable of increasing aerobic adaptations and thus performance, are:

• Altitude: Training and/or sleeping at > ~1800m above sea level (a.s.l.).

• Heat: active (during training) or passive (hot bath, sauna) exposure to a body core temperature of 38.5-39 °C.

So, to be clear, they are both potentially capable of increasing performance in temperate sea-level conditions, not just at altitude or at a high environmental temperature.

• Altitude exposure has been used with endurance athletes since 1960s. The lower partial pressure of oxygen (hypoxic stimulus) at high altitude increases erythropoietin production, which in turn stimulates an increase in haemoglobin mass (HB-mass). As haemoglobin is the oxygen blood transporter, an increase in HB-mass permits more oxygen to arrive at working muscle and so to increase performance.

• Long term regular post-exercise heat exposure to increase performance even in a temperate environment represents a more recent exercise physiology’s frontier, that has been thoroughly investigated only in the last ~5 years. Here its mechanism of action:

  • an increase in plasma volume which, in turn, permits an increase in cardiac stroke volume (more blood can be pumped to the muscles).

  • an increase in mitochondrial density which favours oxygen utilisation at muscular level.

  • an increase in haemoglobin mass which permits to carry more oxygen through the blood to the muscles.

With the aim to maximize performance, it can be interesting to not just use altitude or heat training in isolation, but to understand what is the best way to combine them together: doing heat training at altitude, sleeping at altitude while doing heat training at sea level, planning a heat training block straight after an altitude camp, etc. ….

What is the best way to combine altitude and heat exposure to optimize performance at sea level and cool temperature?

A review of the scientific literature published by Professor Olivier Girard (University of Western Australia) and Colleagues on International Journal of Sports Physiology and Performance in 2024 tried to answer this question. (1)

BONUS ‘SCIENTIFIC LEARNING’ MOMENT:

What is a scientific review of the literature: it is a retrospective analysis of all the data published on a given topic. The indications given by literature reviews are usually more reliable than the data of a single study. Why? Because the results of a single study could be influenced by chance or the specific study design employed, while a review analysing the data coming from many studies minimize the risk of biases.

Have a good read!

1. SIMULTANEOUS APPROACH: HEAT AND HYPOXIC STIMULUS WITHIN THE SAME TRAINING SESSIONS