Table 2.

Application domain of wearable systems proposed in the included studies according to the concept they investigate.

Type of fatigue/Application field	General-purpose	Healthcare	Sport and exercise	Transportation	Other occupations	Other applications	Total # studies
Mental fatigue	#5	#4		#7	#1, #2, #6, #8	#3	8
Vigilance detection	#9				#10, #11		3
Drowsiness	#25, #30, #31			#7, #12–#24, #26, #28, #32–#44	#27, #29		34
Physical fatigue	#47	#52, #55	#48, #49, #56		#45, #46, #50, #51, #53, #54		11*
Muscle fatigue		#58	#60		#57, #59		4
Total # studies	6	4	4	29*	15*	1	59*

^*Article #7 addresses both drowsiness and mental fatigue; articles #46 and #53 use data from the same study.