Table 3.

Subgroup analyses of the effect of exercise on depression in adolescents

Variable	Categories		Number of comparisons (number of participants)	Heterogeneity test results		Meta-analysis results
				Q value	I2 value	SMD effect size (95% CI)	P value
Exercise type	Depression	Aerobic	5 (160)	6.02	35.29%	− 0.59 (− 1.01, -0.17)	0.01
		Whole-body muscle vibration training	1 (35)	–	–	–	–
	Depressive symptoms	Aerobic	7 (453)	21.70	76.91%	− 0.85 (− 1.29, -0.40)	< 0.01
		Resistance + aerobic exercise	2 (86)	4.78	79.07%	− 1.25 (− 2.40, -0.10)	0.03
		Yoga	4 (471)	0.91	0%	− 0.12 (− 0.30, 0.07)	0.22
Exercise program duration (weeks)	Depression	6	4 (158)	5.84	47.46%	− 0.61 (− 1.07, 0.15)	0.01
		9–12	2 (37)	0.18	0%	− 0.55 (− 1.21, 0.11)	0.10
	Depressive symptoms	8	4 (204)	2.79	0%	− 0.82 (− 1.11, -0.52)	< 0.01
		10–12	6 (375)	25.97	86.46%	− 0.57 (− 1.18, 0.04)	0.07
		> 12	3 (431)	20.12	95.18%	− 0.76 (− 1.73, 0.21)	0.12
Exercise session duration (min)	Depression	30	4 (119)	2.72	0%	− 0.76 (− 1.13, -0.38)	< 0.01
		45	2 (76)	0.04	0%	− 0.21 (− 0.67, 0.24)	0.35
	Depressive symptoms	30–45	6 (466)	25.32	87.31%	− 0.58 (-1.18,0.01)	0.06
		75–120	5 (460)	26.51	87.84%	− 0.80 (− 1.38, -0.21)	0.01
Exercise frequency (sessions/week)	Depression	3	4 (126)	5.80	48.59%	− 0.58 (-1.11, -0.05) )	0.03
		4	2 (69)	0.03	0%	− 0.60 (-1.08, -0.12)	0.01
	Depressive symptoms	2	3 (420)	0.49	0%	− 0.10 (-0.29, 0.10)	0.33
		3	10 (590)	3.74	76.47%	− 0.87 (-1.25, -0.49)	< 0.01
Exercise intensity	Depression	Moderate	1 (24)	–	–	–	–
		Self-selected	1 (65)	–	–	–	–
	Depressive symptoms	Moderate	2 (69)	1.39	28.18%	− 1.59 (-2.24, -0.94)	< 0.01
		High	2 (84)	0.06	0	− 0.65 (-1.08, -0.21)	< 0.01