Table 1.
Characteristics of the studies included in the systematic review and meta-analysis
| Study | Subjects | n | Study design | Physical exercise | Blood draw | Measurement methods |
|---|---|---|---|---|---|---|
|
Bouillon (2006) [22] |
Seven female triathletes and seven recreational active females, 32.8 ± 4.5 years | 14 | RCT, cross-over design (exercise, control) | Cycling, 60 min at 60% VO2max (moderate) | Pre, post, recovery (120 min) | Cytotoxicity in %; whole blood, 51Cr release assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Brenner (1996) [11] |
Moderately fit males, 27.1 ± 3.0 years | 11 | RCT, cross-over design (23 °C-exercise, 23 °C-control, 40 °C-exercise, 40 °C-control) | Cycling, 2 × 30 min at 50% VO2max (moderate) | Pre, post, recovery (180 min) | Cytotoxicity in %; PBMC; 51Cr release assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Brenner (1999) [26] |
Moderately fit males, 24.9 ± 2.3 years | 8 | RCT, cross-over-design (all-out, endurance, resistance, control) | Cycling/resistance training, 5 min at 90% (high), 20 min at 60% VO2max (moderate), 5 strength exercises at 60% of 1-RM (moderate) | Pre, post, recovery (45 min) | Cytotoxicity in %; PBMC, 51Cr release assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Flynn (1999) [23] |
Healthy females, 72.8 ± 4.2 years | 29 | RCT, exercise (n = 15) vs. control (n = 14) | Resistance training, 4 strength exercises at 80% of 1-RM (high) | Pre, post, recovery (120 min) | Cytotoxicity in %; whole blood, 51Cr release assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Gannon (1998) [12] |
Recreational active males, 26.3 ± 5.4 years | 10 | RCT, cross-over design (exercise, naltrexone, control) | Cycling, 120 min at 65% VO2max (vigorous) | Pre, post, recovery (120 min) | Cytotoxicity in %; PBMC, flow cytometric assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Lee (2005) [27] |
Healthy males, 26.5 ± 1.5 years | 18 | RCT, exercise (n = 9) vs. control (n = 9) | Qi-training, 60 min exercise (light) | Pre, post, recovery (120 min) | Cytotoxicity in %; PBMC, LDH release of K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
McFarlin (2003) [28] |
Healthy males, 21.6 ± .4 years | 10 | RCT, cross-over design (two bouts, AM-only, PM-only, control) | Cycling, 3 × 20 min at 70% VO2max with each segment initially 5 min at 50% VO2max (vigorous) | Pre, post, recovery (120 min) | Cytotoxicity in %; whole blood, 51Cr release assay, K562 cells; NKCA |
|
McFarlin (2005) [24] |
Postmenopausal females, 72.1 ± 6.4 years | 25 | CT, exercise (n = 19) vs. control (n = 6) | Resistance exercise, 9 strength exercises at 80% of 1-RM (high) | Pre, post, recovery (120 min) | Cytotoxicity in %; whole blood, 51Cr release assay; K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Miles (2002) [29] |
Male runners, 31.2 ± 7.1 years | 10 | RCT, exercise (n = 6) vs. control (n = 4) | Running, 60 min treadmill at 80% VO2max (vigorous) | Pre, post, recovery (90 min) | Lytic index; whole blood, 51Cr release assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Moyna (1996) [31] |
Healthy males and females, 24.1 ± 2.8 years | 64 | RCT, exercise (n = 32) vs. control (n = 32) | Cycling, 18 min in total with 6 min at 55% VO2peak, 6 min at 70%, 6 min at 85% (vigorous) | Pre, post, recovery (120 min) | Lytic units; whole blood, 51Cr release assay, K562 cells; NKCA, NK-cell count (via flow cytometry) |
|
Palmo (1995) [30] |
Non-trained males, 20–29 years | 16 | CT, exercise (n = 8) vs. control (n = 8) | Eccentric exercise, 4 × 5 min one-legged exercise (moderate) | Pre, post, recovery (240 min) | Cytotoxicity in %; PBMC, 51Cr release assay; K562 cells; NKCA |
|
Strasner (1997) [25] |
Healthy females, 24.8 ± 3.9 years | 8 | RCT, cross-over design (vigorous, light, control) | Cycling, 25 min at 80% VO2max (vigorous), 25 min at 40% VO2max (light) | Pre, post, recovery (90 min) | Cytotoxicity in %; PBMC, 51Cr release assay, K562 cells; NKCA |