During exposure to temperature extremes or hypoxia (low oxygen levels), cells increase their expression of heat shock proteins to stabilize unfolded proteins and repair damaged ones. This phenomenon, referred to as the heat shock response, occurs at the expense of other cellular proteins to protect the cell. Evidence from a 2016 study suggests that the heat shock response enhances athletic performance in low-oxygen environments characteristic of high altitudes.

The study involved 21 elite cyclists who engaged in ten 60-minute training sessions in either low-oxygen or hot conditions. Before and after the intervention, they performed a time trial, where researchers tested their tolerance to low-oxygen levels.

The researchers found that training during heat exposure improved athletic performance nearly as well as low oxygen exposure. Expression of heat shock protein 72 and hypoxia-inducible factor 1-α, a protein that mediates the body’s response to low oxygen levels, increased in both scenarios.

Heat-shock proteins comprise a large, highly conserved family of proteins that are present in all cells. They play prominent roles in many cellular processes, including immune function, cell signaling, and cell-cycle regulation. Cells maintain a constant level of HSPs to facilitate aspects of the protein synthesis machinery, including assembly, folding, export, turn-over, and regulation. However, stress can upregulate HSP production.

These findings suggest that training in a hot environment enhances performance in low-oxygen settings. Learn more about heat exposure via sauna use in our comprehensive overview article.

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