Women with metabolic syndrome show similar health benefits from high-intensity interval training than men
Question
Do women and men with metabolic syndrome differ in cardiorespiratory fitness, maximal fat oxidation, body composition, and metabolic syndrome component responses after 16 weeks of supervised high-intensity interval training?
Summary
This single-arm supervised cycling HIIT study followed 119 middle-aged adults with metabolic syndrome for 16 weeks to test whether women and men responded differently. The 43-minute sessions were performed 3 times per week and used 4 by 4-minute intervals at 90% peak heart rate with active recovery. Cardiorespiratory fitness, ventilatory-threshold measures, oxygen uptake efficiency slope, maximal fat oxidation, blood pressure, waist circumference, body weight, fat mass, and metabolic syndrome Z-score improved after training, with no meaningful sex difference in progression. No adverse events were reported, but the study lacked a non-exercise control group.
Methodology
- 119 Caucasian adults of European descent with metabolic syndrome; 63 women and 56 men.
- 119 participants.
- Stationary cycling.
- Work intervals: 4 minutes at 90% HRpeak.
- Recovery: 3 minutes active recovery at 70% HRpeak.
- Intensity: 90% HRpeak for work intervals; 70% HRpeak for warm-up and recoveries.
- 43 minutes.
- 3 sessions per week.
- 16 weeks.
- Prospective pre-post intervention analysis of the aerobic-training-only branch of a larger study, comparing changes over time between women and men.
- VO2max, Ventilatory threshold and OUES, Metabolic syndrome components and MetS Z-score, and Blood pressure were tracked.
Outcomes
VO2max
VO2max increased in women from 18.4 +/- 3.7 to 21.5 +/- 4.3 mL/kg/min and in men from 25.1 +/- 4.8 to 28.7 +/- 5.1 mL/kg/min, with no significant time by gender difference.
Time p<0.001; time by gender p=0.280 for mL/kg/min.
Cardiorespiratory fitness surrogate measures
VO2 at ventilatory threshold, OUES, and VE/VCO2 slope improved after training without sex-differential progression.
VO2 at VT time p<0.001, time by gender p=0.184; OUES time p<0.001, time by gender p=0.915; VE/VCO2 slope time p<0.001, time by gender p=0.484.
Maximal fat oxidation
MFO increased in absolute and fat-free-mass-normalized values similarly in women and men.
Absolute MFO time p<0.001, time by gender p=0.095; normalized MFO time p<0.001, time by gender p=0.713.
Metabolic syndrome components
Blood pressure, waist circumference, and MetS Z-score improved, while triglycerides, HDL, and fasting glucose did not significantly change.
SBP, DBP, waist circumference, and MetS Z-score time p<0.001; TG p=0.439, HDL p=0.845, fasting glucose p=0.698.
Safety
No adverse events were reported during training or exercise testing.
Insights
- A 4 by 4-minute cycling HIIT structure performed 3 times weekly can improve multiple fitness and cardiometabolic measures in supervised adults with metabolic syndrome.
- For this heart-rate-prescribed protocol, women and men had similar relative adaptation despite baseline differences.
- Body-weight reduction was more strongly associated with MetS Z-score improvement than CRF changes in both sexes.
- Clinical translation depends on screening, heart-rate monitoring, and supervision.
Limitations
- No non-exercise control group.
- No complete heart-rate records for every participant and session.
- Possible unmeasured changes in habitual diet or daily physical activity.
- No direct cardiac, pulmonary, or mitochondrial measurements.
- Only participants meeting true VO2max criteria and attending at least 85% of sessions were included in post-training evaluation.
Safety
- No adverse events were reported among volunteers during training or exercise testing.
- Participants underwent medical screening and resting ECG before testing.
- Exercise testing included ECG and blood-pressure monitoring.