Table 2.

Prediction of physiological parameters using a linear mixed-effects model (n = 18)

	In-ear temperature (°C)	Heart rate (beats/min)	Mean skin temperature (°C)
Constant (NN)	37.11*** (0.11)	78.06*** (2.01)	31.93*** (0.18)
Time	0.03*** (0.00)	− 1.09*** (0.02)	0.08*** (0.01)
NP	0.20*** (0.00)	2.36*** (0.06)	0.28*** (0.02)
WN	0.50*** (0.00)	1.62*** (0.06)	0.87*** (0.02)
WP	0.55*** (0.00)	5.12*** (0.06)	1.1*** (0.02)

Standard errors are given in parenthesis

The applied settings (NN: 22 °C, NP, 22 °C and personal protective equipment (PPE), WN: 27 °C and WP: 27 °C and PPE) were included as fixed effects in the regression model

***p < 0.001, **p < 0.01, *p < 0.05