Table 1.
Characteristics of the selected studies.
| No. | Authors | Country | Sample (E/C) | Subjects Age (Years) | Sources of Participants | Gender | Exercise Protocol | Control Group | Main Outcomes | Region |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | S. Donati Zeppa et al., 2021 [17] | Italy | 17 | 22 ± 2 | healthy college students | both | 36 indoor cycling training sessions during nine wks were performed. | self | Alpha diversity indexes (Chao1, Shannon and Simpson) | V3–V4 |
| 2 | Resende et al., 2021 [18] | Brazil | 12 | 25.18 ± 4.66 | healthy Brazilian men | male | 3 supervised training sessions per wk on non-consecutive days, lasting 50 min each, were performed over 10 wks | self | Alpha diversity index (Shannon) | V4 |
| 3 | Laura Mancin et al., 2022 [19] | Turkey | 16 | 25.5 ± 2.8 | semiprofessional soccer players | male | 8 h of training/wk | self | OTU & Shannon | V3–V4 |
| 4 | Nazareth Castellanos et al., 2019 [20] | Spain | 109 (64 + 45) | 32.17 ± 7.40 | Universidad Europea de Madrid | both | 3 days of exercise per wk for 30 min at a moderate intensity (bicycling at a regular pace, swimming or other fitness activities) | no intervention | Alpha diversity indexes (Chao1, Shannon and Simpson) | V3–V4 |
| 5 | Fei Zhong et al., 2022 [21] | China | 8 | 66.38 ± 4.07 | community | female | 4 times per wk. Each session lasted approximately 60 min of combined aerobic exercise (20 min) and resistance exercise (25 min) | self | Alpha diversity indexes (Chao1, Shannon and Simpson) | V3–V4 |
| 6 | Rebecca J. H. M. Verheggen et al., 2021 [22] | Netherlands | 14 | 51 ± 11 | inactive participants with obesity | 50% | 8 wks’ cycling exercise on an ergometer (Lode), starting with a 5-min warm-up, followed by 50 min of exercise at 65% to 85% of the individual HRR, and ending with a cooldown of 5 min. | self | Alpha diversity indexes (Chao1, Shannon and Simpson) | V5–V6 |
| 7 | Lucas Moitinho-Silva et al., 2021 [23] | Germany | 24 (13 + 11) | 30 ± 9.9 | healthy physically inactive German male and female | both | run 3 times per wk for at least 30 min for 6 wks | con | Alpha diversity indexes (Chao1, Shannon and Simpson) | V1–V2 |
| 8 | Siobhan F Clarke et al., 2014 [14] | Ireland | 63 (40 + 23) | 29 ± 4 | Male elite professional rugby players | male | NA | no intervention | Alpha diversity indexes (Chao1, Shannon and Simpson) | V4 |
| 9 | L. Torquati et al., 2022 [15] | Australia | 12 | 63.29 ± 6.625 | T2D | both | HIIT or MICT for 8 weeks | self | Alpha diversity indexes (Chao1, Shannon and Simpson) | NA |
| 10 | Viktor Bielik et al., 2022 [24] | Slovakia | 12 | 16–25 | swimmers competitive at the national level. The athletes came from two swimming clubs. | both | HIIT for 7 wks | self | Alpha diversity indexes (Chao1, Shannon and Simpson) | V1–V3 |
| 11 | Elizabeth A Rettedal et al., 2020 [25] | New Zealand | 29 | 20–45 | lean and overweight men | male | nine sessions of cycle ergometer HIIT on non-consecutive days over 3 wks | self | Alpha and Beta diversity | V3–V4 |
| 12 | YeonGyun Jung et al., 2020 [26] | Korea | 104 | N/A | navy trainees | both | through basic military training, and cardio and weight training performed together every day for 8 wks | self | Alpha and Beta diversity | V4–V5 |
| 13 | Mariangela Tabone et al., 2021 [27] | Spain | 40 | 35.79 ± 8.01 | different cross-country athletes’ teams in Madrid, Spain | male | ran with a slope of 1% at a speed of 10 km/h, with increments of 0.3 km/h every 30 s until volitional exhaustion. | self | Alpha and Beta diversity | V3–V4 |
| 14 | Owen Cronin et al., 2020 [28] | Ireland | 52 (25 + 27) | 35 (28, 38) | physically inactive for at least 3 months prior | both | an 8-wk (3 times per wk) mixed aerobic and resistance exercise training program with protein supplementation | protein supplementation | Alpha diversity indexes (Chao1, Shannon and Simpson) | NA |
| 15 | Eveliina Munukka et al., 2018 [29] | Finland | 17 | 36.8 ± 3.9 | sedentary overweight women | female | a 6 wks endurance exercise | self | Alpha diversity indexes (Chao1, Shannon and Simpson) | V4 |
| 16 | Shaodong Wei et al., 2022 [30] | Danish | 86 (60 + 26) | 54.3 ± 8.9 | above 18 years old, T2D diagnosis for less than 10 years | both | five to six weekly aerobic sessions whereof two to three sessions were combined with resistance training; 12 months | standard care group | Alpha and Beta diversity | V3–V4 |
| 17 | C. J. Stewart et al., 2017 [31] | UK | 20 (10 + 10) | 26.9 ± 5.06 | a duration of diabetes > 5 years | male | aerobic-based exercise for a minimum of 30 min at a time, at least three times per week | self | V4 | |
| 18 | Carlo Bressa et al., 2017 [32] | Spain | 40 (19 + 21) | 30.7 ± 5.9 | premenopausal women | female | at least 3 h of physical exercise per week | sedentary women | Alpha diversity indexes (Chao1, Shannon H and Simpson) | V3–V4 |
| 19 | Xueqing Zhang et al., 2023 [33] | China | 93 | 20.23 ± 0.62 | College Students with IDA | both | 8 wk of Tai Chi, 3 times a wk, 60 min, or 8-week conventional exercise, 60 min, 3 times per wk | no intervention | Alpha diversity (Shannon, Chao1, Simpson) & Beta diversity | V3–V4 |
| 20 | Camilla J Williams et al., 2022 [34] | Australia | 40 (20 + 20) | 30.4 ± 9.8 | sedentary and apparently healthy adults | both | 6 wk of supervised HIIT (4 × 4-min bouts at 85–95% HRmax, 3·wk–1) | self | Alpha diversity indexes (Shannon) | NA |
| 21 | Runtan Cheng et al., 2022 [35] | China | 40 (22 + 18) | 59.4 ± 0.5 | nonalcoholic fatty liver disease | both | progressive aerobic exercise training program, 2–3 times a wk, 30–60 min per session with 60–75% of the VO2Max. | no intervention | Alpha diversity indexes (Shannon) | V3–V4 |
| 22 | Kristen S.Smith et al., 2022 [36] | USA | 24 | 20.8 ± 1.7 | young female adults | female | 10 wks of Resistance T raining | self | Alpha diversity indexes (Shannon and Simpson) | V4 |
| 23 | Dongyang Kang et al., 2023 [37] | China | 30 (15 + 15) | N/A | basketball players from university | male | 90 min Tai Chi, 6 days per week, 5 months | no intervention | OUT & Alpha diversity indexes (Chao1, Shannon, Faith’s PD) | V3–V4 |
| 24 | Yuping Zhu et al., 2023 [38] | China | 32 | 30.30 ± 5.28 | MA dependent individuals | both | aerobic exercise, 3 times per wk, 60 min, 8 wks. | self | Alpha diversity indexes (Shannon) | V3–V4 |
| 25 | Shrushti Shah et al., 2023 [39] | Canada | 110 | 56.23 ± 6.36 | People with normal BMI and High BMI | both | IPAQ | people with low physical activity | Alpha diversity indexes (Shannon) & Beta diversity (Bray–Curtis dissimilarity metrics) | V3–V4 |
BMI: body mass index; wk: week/s; VO2max: maxima oxygen uptake; HRR: heart rate reserve; HIIT: high-intensity interval training; MICT: Moderate Intensity Continuous Training; T2D: type 2 diabetes; HRmax: maximal heart rate; N/A: Not Applicable; MA: methamphetamine, IPAQ: International Physical Activity Questionnaire; OTU: Operational Taxonomic Units; IDA: Internet addiction disorder.