Table 3.

The fixed effect estimates on HRV indices, controlling for examiner and flight profile number.

Variable	SDNN (ms) (R-Squared = 0.393)			RMSSD (ms) (R-Squared = 0.443)			LF/HF (R-Squared = 0.189)
	Estimate	Std. Error	p-Value	Estimate	Std. Error	p-Value	Estimate	Std. Error	p-Value
Intercept	19.21	1.54	<0.001	12.89	1.20	<0.001	5.96	0.49	<0.001
Age > 50	0.00 (Reference)
41 < Age < 50	11.62	0.86	<0.001	4.13	0.68	<0.001	1.33	0.27	<0.001
30 < Age < 40	18.11	0.78	<0.001	16.56	0.61	<0.001	−3.28	0.25	<0.001
BMI > 30	0.00 (Reference)
25 < BMI < 30	4.20	0.91	<0.001	5.18	0.71	<0.001	−0.65	0.29	0.026
20 < BMI < 25	3.54	0.85	<0.001	4.37	0.67	<0.001	−0.28	0.27	0.305
Regularly fly 65+ hours/month in simulation	0.00 (Reference)
Regularly fly 65+ hours /month as a pilot	6.16	0.82	<0.001	0.43	0.64	0.507	1.36	0.26	<0.001
High CO2	0.00 (Reference)
Medium CO2	0.64	0.73	0.384	−0.15	0.57	0.797	0.64	0.23	0.006
Low CO2	0.10	0.75	0.895	−0.78	0.59	0.182	0.78	0.24	0.001
Gap time	0.00 (Reference)
Difficulty A	−5.53	1.74	0.002	−2.86	1.36	0.036	−0.36	0.55	0.509
Difficulty B	−2.03	1.37	0.138	−1.40	1.07	0.191	0.22	0.43	0.605
Difficulty C	−4.13	1.27	0.001	−2.66	1.00	0.008	−0.24	0.40	0.558