Table 2: Classification of the relative strain index levels (^{Blażejczyk, 2011}).

Amount of Relative Strain Index	Interpretation of Index
RSI < 0.15	Climate comfort
0.15 ≤ RSI < 0.25	Discomfort for sensitive individuals such as the elderly and children
0.25 ≤ RSI < 0.35	Discomfort for all people
0.35 ≤ RSI < 0.45	The risk of exposure to excessive heat (heat stroke risk) for 50% of people and more
RSI ≥ 0.45	The risk of hyperthermia for all people