. 2021 Dec 23;7:99. doi: 10.1186/s40798-021-00390-y

Table 2.

Sex-based comparisons of outcomes related to cardiorespiratory fitness, insulin sensitivity, glycemic control, and mitochondrial content following low-volume interval training

References	Sample size (M/W)	Population					Intervention		Outcome
References	Sample size (M/W)	Descriptives	Age (yr)	BMI (kg/m²)	${\dot{V} O}_{2}$ peak (ml/kg/min)	Menstrual cycle phase; HC use	Interval training protocol	Duration (wk); frequency (sessions/wk); exercise mode	Sex-specific results
Astorino et al. [68]	11/9	Rec active	M: ~ 25 W: ~ 25	~ 25 ~ 22	~ 46 ~ 41	NR; NR	4–6 × 30 s 'all out' sprints, 5 min recovery	2–3 wks; 2–3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W
Bagley et al. [10]	24/17	Healthy	M: ~ 38 W: ~ 41	~ 26 ~ 22	~ 43 ~ 34	NR; NR	4 × 20 s 'all out' sprints, 2 min recovery	12 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in W > M (p = 0.009) ↔ FPG or FPI in M and W ↔ HOMA-IR in M and W
Bonafiglia et al. [72]	9/12	Healthy, rec active	M: ~ 20 W: ~ 20	~ 25 ~ 23	~ 45 ~ 39	NR; NR	8 × 20 s at ~ 170% ${\dot{V} O}_{2}$ peak, 10 s rest	3 wks; 4 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W
Bostad et al. [75]	6/9	Healthy, untrained	M/W: ~ 21	~ 24	~ 37	Uncontrolled; 4 participants using OC	3 × 20 s ‘all out’ sprints, 2 min recovery	12 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W (M > W, p < 0.01)
Esbjörnsson Liljedahl et al. [163]	6/10	Healthy, rec active	M: ~ 26 W: ~ 25	~ 23 ~ 22	NR NR	NR; NR	3 × 30 s 'all out' sprints, 20 min rest	4 wks; 3 sessions/wk; cycling	↔ CS maximal activity in M and W
Gillen et al. [53]	7/7	Obese, inactive	M: ~ 29 W: ~ 30	~ 31 ~ 29	~ 31 ~ 28	Uncontrolled; NR	3 × 20 s 'all out' sprints, 2 min recovery	6 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W ↓ 24 h blood glucose mean and AUC in M and ↔ in W (p < 0.05) ↔ FPG in M and W ↓ FPI in M and W ↓ HOMA-IR in M and W ↑ CS maximal activity in M and W ↑ COXIV protein content in M and W
Metcalfe et al. [69]	7/8	Healthy, inactive	M: ~ 26 W: ~ 24	~ 24 ~ 23	~ 36 ~ 33	Trials separated by ~ 8 wks; NR	2 × 20 s 'all out' sprints, ~ 3 min recovery	6 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W ↑ OGTT insulin sensitivity in M and ↔ in W
Metcalfe et al. [71]	17/18	Healthy, inactive	M: ~ 33 W: ~ 36	~ 25 ~ 24	~ 39 ~ 32	Trials separated by ~ 8 wks; NR	2 × 20 s 'all out' sprints, ~ 3 min recovery	6 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W ↔ OGTT glucose or insulin AUC in M and W
Phillips et al. [76]	64/72	Impaired glucose tolerance and/or BMI > 27, inactive	M/W: ~ 36	~ 32	~ 27	NR; NR	5 × 1 min at 125% ${\dot{V} O}_{2}$ peak, 1 min recovery	6 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W [M > W for absolute (L/min), p < 0.001; no difference in relative (%), p > 0.05] ↓ HOMA-IR in M and W
Scalzo et al. [70]	11/10	Healthy, rec active	M: ~ 22 W: ~ 23	~ 22 ~ 23	~ 43 ~ 40	Uncontrolled; 1 participant using OC	4–8 × 30 s, 4 min recovery	3 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W > MPS in mitochondrial fraction in M versus W (trend p = 0.056) > MPS in cluster of mitochondrial proteins in M versus W (p < 0.001) ↑ CS protein content in M and W ↔ COXIV protein content in M and W
Søgaard et al. [73] & Chrøis et al. [138]	11/11	Healthy, inactive	M: ~ 63 W: ~ 63	~ 31 ~ 31	~ 27 ~ 23	NR; NR	5 × 1 min at ~ 125% PPO, 1.5 min recovery	6 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and W ↑ Clamp insulin sensitivity in M and W (M > W trend p = 0.068) ↔ OGTT glucose or insulin AUC in M and W ↔ FPG or FPI in M and W ↓ HbA1c in M and ↔ in W (p < 0.001) ↑ CS maximal activity in M and W ↑ ETC protein content in M and W ↑ Mitochondrial respiratory capacity in M and ↔ in W (p < 0.001)
Weber et al. [74]	7/7	Healthy, untrained	M: ~ 24 W: ~ 23	~ 26 ~ 23	~ 44 ~ 40	Tested in follicular phase; NR	3 × 2 min at ~ 100–120% of ${\dot{V} O}_{2}$ peak, 6 min recovery	8 wks; 3 sessions/wk; cycling	↑ ${\dot{V} O}_{2}$ peak in M and ↔ in W (p < 0.05)

Statistical significance for the sex by time interaction or independent t-test is presented for outcomes demonstrating a sex-based difference. Body mass index (BMI) was not reported in some studies [68, 69, 72, 74, 75, 163] and was estimated using the mean height and weight values reported. Abbreviations: > greater; ↑ increase; ↓ decrease; ↔ no change, AUC area under the curve; CGM continuous glucose monitor; COXIV cytochrome c oxidase subunit IV; CS citrate synthase; ETC electron transport chain; FPG fasting plasma glucose; FPI fasting plasma insulin; HbA1c glycated hemoglobin; HC hormonal contraceptive; HOMA-IR homeostatic model assessment of insulin resistance; M men; MPS muscle protein synthesis; NR not reported; OC oral contraceptive; OGTT oral glucose tolerance test; Rec active recreationally active; PPO peak power output; ${\dot{V} O}_{2}$ peak peak oxygen uptake; W women