A Practical and Time-Efficient High-Intensity Interval Training Program Modifies Cardio-Metabolic Risk Factors in Adults with Risk Factors for Type II Diabetes

Figures

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  Figure 1. Flow chart of participant contact, screening, and retention through the phases of the study.

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  Figure 2. An analysis of the training response to 5-by-1 HIT for V˙O2 max, MAP and HOMA-IR in men and women. Inter-participant variability in response to HIT is large for both men and women, but on average both genders respond to a similar extent. Abbreviations: V˙O2 max, maximal aerobic capacity; MAP, mean arterial pressure; HOMA-IR, homeostatic model assessment of insulin resistance; HIT, high-intensity interval training.

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  Figure 3. Comparison of the inter-individual variability to exercise training contrasting short-term high-intensity training with longer-term high-volume submaximal training. The training response to 6-weeks 5-by-1 high-intensity interval training [(A,C,E); black bars] and our previously published 8-month STRRIDE AT and AT/RT exercise training study [(B,D,F); gray bars] for V˙O2 max, MAP, and HOMA-IR. Training-induced changes in both V˙O2 max (A,B), MAP (C,D), and HOMA-IR (E,F) vary considerably in both studies and to a similar extent. Abbreviations: AT, aerobic training; RT, resistance training; V˙O2 max, maximal aerobic capacity; MAP, mean arterial pressure; HOMA-IR, homeostatic model assessment of insulin resistance.

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  Figure 4. Presentation of the responder frequency for the three main clinical biomarkers considered in this study [high-intensity interval training (HIT)] and comparison with our previously published endurance training (ET) study. Each individual was assessed for improvement in V˙O2 max, mean arterial pressure, or HOMA-IR, greater than the laboratory error, and the percentile frequency of 0, 1, 2, or 3 from three improvements was calculated. For sake of comparison, this is plotted side-by-side with the percentile frequency of 0, 1, 2, or 3 gains based on numerical improvements (a criteria that would be considered unreliable by most). Approximately 40% of subjects demonstrate improvement in only one health biomarker, while between 4 and 9% demonstrate no reliable improvement in any.

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  Figure 5. Presentation of the average retention of the training-induced changes observed 3 weeks after cessation of 5-by-1 high-intensity interval training. A value of 100% represents the training effect and a value of 0% indicates that the training effect is lost 3 weeks after training (under sedentary conditions). Significant differences from baseline: **p < 0.01, ***p < 0.001. Significant differences from post-training: ^^^p < 0.001. Abbreviations: V˙O2 max, maximal aerobic capacity; Wmax, maximal power output; SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure; HOMA-IR, homeostatic model assessment of insulin resistance.