The Impact of High-Intensity Interval Training Versus Moderate-Intensity Continuous Training on Carotid Intima-Media Thickness and Ankle-Brachial Index in Middle-Aged Women
Question
What are the effects of high-intensity interval training compared with moderate-intensity continuous training on endothelial performance indicators, carotid intima-media thickness, ankle-brachial index, lipid profile, and blood pressure in inactive overweight middle-aged women?
Summary
This study randomized inactive overweight women aged 40-50 years to 12 weeks of supervised treadmill HIIT, moderate-intensity continuous training, or usual activity control. HIIT used four 4-minute bouts at 85-95% maximal heart rate with 3-minute active breaks at 50-60% maximal heart rate, three times per week. Carotid intima-media thickness decreased in both exercise groups but not significantly, while right ankle-brachial index increased significantly in the HIIT group. Lipids improved in both training groups, especially total cholesterol and triglycerides for HIIT, but the sample was small and the outcomes are vascular surrogate markers.
Methodology
- Inactive overweight women aged 40-50 years with BMI greater than 27 kg/m2; final groups were HIIT n=10, MICT n=11, and control n=9.
- 33 participants.
- Treadmill walking or running.
- Work intervals: 4 minutes.
- Recovery: 3 minutes at 50-60% maximal heart rate between intervals.
- Intensity: 85-95% maximal heart rate during work intervals.
- 25 minutes work/recovery block plus 5-minute cool-down; warm-up not reported.
- 3 supervised sessions per week.
- 12 weeks.
- Quasi-experimental pre-test/post-test intervention with random allocation to HIIT, MICT, or control.
- Carotid intima-media thickness, Ankle-brachial index, Lipid profile, and Systolic blood pressure were tracked.
Outcomes
Carotid intima-media thickness
Carotid IMT decreased numerically in HIIT from 0.47 +/- 0.09 to 0.45 +/- 0.08 mm and in MICT from 0.49 +/- 0.10 to 0.45 +/- 0.06 mm, while control increased from 0.52 +/- 0.13 to 0.54 +/- 0.13 mm.
Within-group p=0.524 for HIIT, p=0.068 for MICT, p=0.570 for control; between-group p=0.310.
Right ankle-brachial index
Right ABI increased in HIIT from 0.92 +/- 0.09 to 1.06 +/- 0.11; MICT stayed 1.01 +/- 0.16 to 1.01 +/- 0.10; control increased from 0.94 +/- 0.09 to 0.99 +/- 0.08.
HIIT within-group p=0.007; between-group p=0.027; LSD post hoc reported significant difference between MICT and HIIT p=0.009.
Overall ankle-brachial index
Overall ABI increased in HIIT from 0.95 +/- 0.12 to 1.04 +/- 0.12 and in MICT from 1.00 +/- 0.14 to 1.01 +/- 0.09, but neither change was significant.
Within-group p=0.108 for HIIT and p=0.870 for MICT; between-group p=0.217.
Total cholesterol
Total cholesterol decreased in MICT from 201.45 +/- 16.91 to 171.82 +/- 23.52 mg/dL and in HIIT from 194.60 +/- 27.68 to 171.80 +/- 19.88 mg/dL.
Within-group p=0.001 for MICT and p=0.018 for HIIT; between-group p=0.198.
LDL cholesterol
LDL decreased significantly in MICT from 120.27 +/- 12.31 to 101.55 +/- 20.24 mg/dL, but HIIT changed non-significantly from 112.00 +/- 23.39 to 102.70 +/- 16.30 mg/dL.
Within-group p=0.001 for MICT and p=0.162 for HIIT; between-group p=0.081.
Triglyceride
Triglycerides decreased in MICT from 89.63 +/- 22.81 to 71.18 +/- 20.26 mg/dL and in HIIT from 102.20 +/- 41.56 to 71.00 +/- 24.00 mg/dL.
Within-group p=0.001 for MICT and p=0.037 for HIIT; between-group p=0.060.
Systolic blood pressure
Systolic blood pressure did not change significantly in HIIT, MICT, or control.
Within-group p=0.524 for HIIT, p=0.703 for MICT, p=0.788 for control; between-group p=0.743.
Insights
- The study provides a reproducible 4 x 4-minute treadmill HIIT protocol with 3-minute active recoveries for overweight middle-aged women.
- HIIT improved right ABI and some lipid measures, but carotid IMT changes were not significant, so vascular claims should be qualified.
- A moderate continuous comparator of 47 minutes at 60-70% maximal heart rate was used to make the HIIT and MICT protocols isocaloric.
Limitations
- Small sample size.
- Convenience sampling and quasi-experimental design despite random allocation.
- Women-only sample aged 40-50 years.
- Participants with cardiovascular disease and hypertension were excluded.
- Most vascular outcomes did not change significantly.
- Adherence details and adverse-event monitoring methods were not reported.
- Warm-up duration and progression rules were not reported.
Safety
- No adverse events were reported in the article text.
- The study excluded people with cardiovascular disease, hypertension, severe musculoskeletal disorders, and medications such as statins, ACE inhibitors, and certain beta blockers.
- Exercise sessions were supervised and intensity was heart-rate controlled.