Table 3.

Corresponding relation between the mean values of HRV measures and stress level [31].

Variable	Mean Value	Stress Level
SDNN	>50	Non-Stressed, ANS's regulating function and stress coping abilityis good
	35–50	Normal, ANS's regulating function and stress coping ability is normal
	20–35	High, there's risk of developing stress induced disease
	<20	Very High,there's high risk of having chronic stress induced disease
LF/HF	>2.0	Hyper Sympathetic activation, related to acute stress
	0.5–2.0	Normal,clinically considered as ANS balanced status
	<0.5	Hyper Parasympathetic activation, related to chronic stress