(a)
(b)
(c)
(d)
(e)
(f)
Figure 2: Relationships between heart rate and blood pressure variability parameters and core body temperature at the specific stage of the experiment: before_S (before sauna), after_S (after sauna), S_+3 h (3 hours after sauna), and S_+6 h (six hours after sauna). (a) HF-RRI, (b) PSD-RRI, (c) LF-dBP, (d) PSD-dBP, and (e) LF/HF; (abbreviations are listed in the “Nomenclature” section).