Table 1.

Overview about the population characteristics, fNIRS methodology and data processing, exercise characteristics and cognitive testing, and main outcomes of reviewed studies.

First Author	Sample Characteristics—Number of Participants (n)/Mean Age in Years ± SD	Main Findings	Region of Interest (ROI)
Studies conducting an acute bout of physical activity
Ando et al. [120]	Healthy young adults n = 10 m/25.1 ± 3.4	After cycling vs. prior cycling (normoxia): - ↑ oxyHb and TOI in rt. PFC during CT	rt. PFC
Bediz et al. [117]	Healthy young adults HP n = 18 m/21.0 ± 2.6 LP n = 17 m/20.6 ± 2.1	After cycling vs. prior cycling: - ↑oxyHb and total Hb in md. PFC during CT in both groups - ↑deoxyHb in md. PFC during CT in HP - ↑oxyHb and totHb in lt. and md. PFC during CT in HP -PP is correlated with oxyHb	lt., rt. and md. PFC
Byun et al. [8]	Healthy young adults n = 25 (12 f, 13 m)/20.6 ± 1.0	After cycling vs. control condition (sitting): - ↑oxyHb in lt. DLPFC and lt. FPA during CT -oxyHb in lt. DLPFC and lt. FPA are associated with RT in CT	lt. and rt. DLPFC, VLPFC; FPA
Chang et al. [115]	Healthy young adults HC n = 9 f/21.8 ± 1.4 HIR n = 9 f/21.1 ± 1.6 MIC n = 9 f/20.4 ± 1.5 HIA n = 9 f/22.1 ± 1.4	Post-test (neutral condition): - ↓TOI in lt. PFC (HIR vs. CON/MIC) Post-test (incongruent condition): - ↓TOI in lt. PFC (HIR vs. CON/MIC) TOI in rt. PFC (HIR vs. CON/MIC/HIA)	lt. and rt. PFC
Endo et al. [98]	Healthy young adults n = 13 (8 f, 5 m)/23.0 ± 1.0	After cycling vs. prior cycling: - ↑oxyHb in DLPFC during CT (40% and 60% intensity) After cycling vs. control condition (sitting): - ↑oxyHb in DLPFC during CT (60% intensity) (results for 15 min exercise condition/test administration 5 min after exercise cessation)	lt. and/or rt. DLPFC
Faulkner et al. [116]	Healthy young adults n = 17 m/24.6 ± 4.3	After cycling vs. prior cylcing: - ↑ rSO2 in PFC during CT	lt. and rt. PFC
Faulkner et al. [97]	Patients with TIA and HC TIA n = 11 (2 f, 9 m)/65.0 ± 10.0 HC n = 15 (2 f, 13 m)/62.0 ± 7.0	After cycling vs. prior cycling: - ↑oxyHb, deoxyHb and totHb in PFC during CT (for test administration 1.5 min after exercise cessation)	dominant side of PFC 1
Hyodo et al. [7]	Healthy older adults n = 16 (5 f, 28 m)/69.3 ± 3.5	After cycling vs. control condition (sitting): - ↑oxyHb in rt. FPA during CT -oxyHb in rt. FPA is associated with RT in CT	lt. and rt. DLPFC, VLPFC; FPA
Hyodo et al. [77]	Healthy older adults n = 13 (6 f, 7 m)/69.7 ± 2.7 (f); 69.3 ± 2.8 (m)	Cycling vs. dancing: - no significant differences between timepoints or groups	lt. and rt. DLPFC, VLPFC; FPA
Kujach et al. [109]	Healthy, sedentary young adults n = 25 (9 f, 16 m)/20.7 ± 1.9 (f); 21.1 ± 1.9 (m)	After cycling vs. prior cycling: - ↑oxyHb in lt. DLPFC post-exercise during CT -oxyHb in lt. DLPFC is associated with RT in CT	lt. and rt. DLPFC, VLPFC; FPA
Lambrick et al. [119]	Healthy children n = 20 (11 f, 9 m)/8.8 ± 0.8	After running vs. prior running: - ↑oxyHb and totHb in PFC post-exercise during CT (at all three time points) - ↑oxyHb and totHb in PFC post-exercise during CT (1 min vs. 15 min and 30 min post-exercise) -total Hb is associated with Stroop completion time (for intermittent group)	dominant side of PFC 1
Moriya et al. [99]	Patients suffering from stroke n = 11 (4 f, 7 m)/69.6 ± 12.0	After cycling vs. prior cycling: - ↑ oxyHb in rt. PFC post-exercise during CT	rt. and lt. PFC
Murata et al. [78]	Healthy young adults n = 15 (6 f, 9 m)/21.7 ± 2.4; 21.6 ± 3.0 (f); 21.8 ± 2.2 (m)	After cycling vs. prior cycling: - ↓ lt. DLPFC and SMA post-exercise during CT (Go-trials)	rt. and lt. DLPFC, SMA
Ochi et al. [114]	Healthy young adults n = 15 (8 f, 7 m)/20.7 ± 2.1 (18-25)	After cycling (normobaric hypoxia) vs. control condition (sitting/normobaric hypoxia): - ↓oxyHb in lt. DLPFC post-exercise during CT -oxyHb in lt. DLPFC is associated with RT in CT	lt. and rt. DLPFC, VLPFC; FPA
Sudo et al. [108]	Healthy young adults Stretching group n = 8 m/23.9 ± 2.3 Control group n = 8 m/23.8 ± 2.1	After stretching vs. prior stretching: -oxyHb, deoxyHb and TOI in lt. PFC no significant differences between timepoints or groups	lt. PFC
Sudo et al. [105]	Healthy young adults Cycling group n = 18 m/23.2 ± 2.1 Control group n = 14 m/22.3 ± 2.3	After cycling vs. prior cycling: -oxyHb, deoxyHb, totHb and cerebral oxygenation in rt. PFC no differences during CT - Δcerebral oxygenation (TOI) is associated with Δ reaction time	rt. PFC
Tsuchiya et al. [113]	Healthy young adults n = 25 (19 f, 6 m)/19.88 ± 0.60 (18-21)	Housework activities vs. control condition: - ↑oxyHb (trend) in rt. VLPFC during CT (Stroop interference score between post- and pre-sessions)	lt. and rt. DLPFC, VLPFC; FPA
Tsujii et al. [100]	Healthy older adults n = 14 (9 f, 7 m)/65.9 ± 1.0	After cycling vs. control condition (sitting): - ↑ oxyHb in lt. PFC during CT	rt. and lt. PFC
Yamazaki et al. [111]	Healthy young adults n = 14 (6 f, 8 m)/22 ± 0.6	After recumbent cycling vs. prior cycling: - oxyHb no difference in the ROI’s during CT Responders vs. Non-Responders 2: - ↑ (maximum peak) oxyHb in rt. VLPFC during exercise	lt. and rt. DLPFC, VLPFC; FPA
Yanagisawa et al. [6]	Healthy young adults n = 20 (3 f, 17 m)/21.5 ± 4.8	After cycling vs. control condition (sitting): - ↑oxyHb in lt. DLPFC post-exercise during CT -oxyHb in lt. DLPFC is associated with RT in CT	lt. and rt. DLPFC, VLPFC; FPA
Studies conducting long-term physical exercises
Chen et al. [102]	Healthy young adults n = 42 (26 f, 16 m)/22.5 ± 2.0	Post-test vs. pre-test: - ↑ oxyHb in lt. PFC in BMB (incongruent condition)	lt. and rt. PFC
Coetsee et al. [101]	Healthy older adults HIIT n = 13 (10 f, 3 m)/64.5 ± 6.3 MCT n = 13 (10 f, 3m)/61.6 ± 5.8 ReT n = 22 (15 f, 7 m)/62.4 ± 5.1 CON n = 19 (11 f, 8 m)/62.5 ± 5.6	Post-test vs. pre-test: - ↑oxyHb in lt. PFC in CON (naming condition) - ↑deoxyHb in lt. PFC in MCT and HIIT (naming and executive condition) - ↓THI in lt. PFC in MCT (naming and executive condition) - ↓oxyHb in lt. PFC in ReT (Stroop interference effect) - ↓THI in lt. PFC in ReT and MCT (Stroop interference effect)	lt.and rt. PFC
Wang et al. [79]	Healthy older adults n = 12 (8 f, 4 m)/64.25 ± 3.14 (60 - 68)	Post-test vs. pre-test (after Tai-Chi intervention): - no significant differences between timepoints	frontal cortex
Xu et al. [96]	Obese young adults n = 31 (12 f, 19 m)/18.2 ± 3.2	Participants with higher weight reduction vs. participants with lower weight reduction: - ↑ oxyHb in lt. and rt. DLPFC, VLPFC; FPA during CT	lt. and rt. DLPFC, VLPFC; FPA
Cross-sectional studies
Albinet et al. [13]	Healthy older adults n = 40 f/60-77 (low-fit group n = 17/high-fit group n = 17)	High-fit group vs. low-fit group: - ↑ oxyHb in rt. DLPFC Low-fit group: - ↑ oxyHb in rt. DLPFC compared to lt. DLPFC Correlation between hemodynamic responses during CT and physical fitness: -relationship between aerobic fitness (assessed via VO2 max) and cognitive performance is partly mediated by slope coefficient of oxyHb in the rt. DLPFC (at 1.5 s pace condition)	lt. and rt. DLPFC
Cameron et al. [118]	Healthy young adults n = 52 f/20.7 ± 2.3	Correlation between hemodynamic responses during CT and measures of physical activity or cognition: -higher chronic physical activity level is linked to higher oxyHb and superior cognitive performance -correlation between oxyHb and deoxyHb with RT (difficult condition)	rt. PFC
Dupuy et al. [11]	Healthy younger adults n = 22 f/24.6 ± 3.6 (19-34) Healthy older adults n = 36 f/62.9 ± 5.4 (55-72)	High-fit individuals vs. low-fit individuals: - ↑oxyHb in rt. inferior frontal gyrus during CT (naming and executive condition) - ↑totHb in rt. inferior frontal gyrus during CT (naming and executive condition)	lt. and rt., ant. and post. DLPFC and VLPFC
Fabiani et al. [112]	Healthy, high-fit older adults n = 20 (11 f, 9 m)/70.3 ± 4.2 Healthy, low-fit older adults n = 24 (13 f, 11 m)/72.2 ± 5.2	High-fit older adults vs. low-fit older adults: -VO2 peak is correlated with oxyHb but not deoxyHb changes	lt. and rt. occipital cortex
Giles et al. [110]	Healthy young adults n = 74 (50 f, 24 m)/19.55 ± 0.27	Correlation between hemodynamic responses during CT and habitual exercise level: -greater habitual exercise level is associated with↓ oxyHb and totHb during CT (negative and neutral pictures/during preparatory period)	ant. PFC and DLPFC
Hyodo et al. [12]	Healthy older adults n = 60 m/70.3 ± 3.2	Correlation between hemodynamic responses during CT and physical fitness or cognition: -activation in lt. DLPFC is positively associated with VT -activation in lt. DLPFC is negatively associated with Stroop interference time	lt. and rt. DLPFC
Kato et al. [104]	Healthy young adults n = 23 (10 f, 13 m)/22.0 ± 2.2	Correlation between hemodynamic responses during CT and measures of physical activity or sleep duration: -exercise amount is associated with the AUC during CT -exercise amount is correlated with reaction time on fNIRS -percentage of correct responses in CPT-IP are correlated with peak oxyHb -total sleep time is associated with the AUC during CT	lt. and rt. frontal areas
Makizako et al. [107]	Healthy older adults n = 20 (10 f, 10 m)/76.1 ± 6.7 (66-89)	Group with high physical activity level vs. group with low physical activity level: - ↑ oxyHb in lt. and rt. IFG during CT	lt. and rt. IFG
Matsuda et al. [106]	Healthy young adults n = 40 (15 f, 25 m)/20.4 ± 1.1	Group with high physical activity level vs. group with low physical activity level: - ↑oxyHb in lt. DLPFC during CT (Interference condition)	lt. DLPFC
Mücke et al. [103]	Healthy children n = 50 (24 f, 26 m)/10.6 ± 0.3 (low MVPA n = 20/high MVPA n = 30)	Group with low MVPA vs. group with high MVPA: -no significant differences in cortical activity between group with low MVPA and group with high MVPA	lt. and rt. ant. PFC; lt. and rt. intermediate and md. frontal region
Suhr and Chellenberg [10]	Healthy, older adults n = 22 (17 f, 5 m)/68.26 ± 8.39 (54-89)	Correlation between hemodynamic response during CT and measures of physical activity or cognition: -hours of physical activity are associated with rSO2 -memory performance is correlated with rSO2	lt. and rt. DLPFC

Ant: anterior; AUC: area und the curve; BMB: Baduanjin Mind-Body Intervention; CON: control group; CPT-IP: continuous performance test-identical pairs; CT: cognitive testing; deoxyHb: deoxygenated hemoglobin; DLPFC: dorsolateral prefrontal cortex; f: female; FPA: frontopolar area; HC: healthy controls; HIA: high-intensity aerobic exercise; HIIT: high-intensity aerobic interval training; HIR; high-intensity resistance training; HP: high performer; IFG: inferior frontal gyrus; LP: low performer; lt.: left; m: male; MCT: moderate continuous aerobic training; md.: middle; MIC: moderate-intensity exercise combining resistance training and walking; min: minute; MVPA: moderate-to-vigorous physical activity; n = number of participants; oxyHb: oxygenated hemoglobin; PFC: prefrontal cortex; post.: posterior; PP: peak performance in exercise test; ROI: region of interest; ReT: resistance training; rt.: right; RT: reaction time; s: second; SD: standard deviation; SMA: supplementary motor area; THI: total hemoglobin index; TIA: patients with transient ischemic attack; TOI (or rSO₂): tissue oxygenation index; totHb: total hemoglobin; VLPFC: ventrolateral prefrontal cortex; VO₂ max/VO₂ peak: maximal oxygen uptake; vs.: versus; VT: ventilatory threshold; ↑: significant increase; ↓: significant decrease / ¹ In right-side dominant participants the probe is placed over right prefrontal cortex while in left-side dominant participants the probe is placed over left prefrontal cortex. / ² Responders are participants who showed improved task performance in cognitive testing conducted at 5 min after cycling. Non-responder showed no significant improvement in cognitive functions after performing the acute bout of cycling.