I'd like to see a bit more detailed methods.

- How was the controlling for the other factors done? A linear model?

- What were the sauna vs non-sauna baseline HRs in fig 1? Could you plot raw averages?

- Was the min HR explicitly computed during the night (in Fig 2), or was it assumed min HR occurs during the night?

- Reporting only significant results is not prudent even with multiple comparisons corrections, please report all tests made