PMID 38812051

Research
All papers

Effects of HIIT training and HIIT combined with circuit resistance training on measures of physical fitness, miRNA expression, and metabolic risk factors in overweight/obese middle-aged women

Pashaei Z, Malandish A, Alipour S, Jafari A, Laher I, Hackney AC, Suzuki K, Granacher U, Saeidi A, Zouhal H

Question

What are the effects of 10 weeks of HIIT versus HIIT combined with circuit resistance training on physical fitness, miRNA expression, and metabolic risk factors in overweight or obese middle-aged women?

Summary

This randomized 10-week trial compared running HIIT with a combined program of running HIIT plus circuit resistance training in overweight or obese middle-aged women. Both programs reduced body mass, BMI, and body-fat percentage and improved VO2max over time, but only the combined program produced a clearly larger strength gain. The single-mode HIIT group increased miR-155 and showed lipid changes including lower triglycerides and LDL cholesterol; the combined group lowered total cholesterol but also lowered HDL cholesterol.

Methodology

  • Twenty-seven overweight or obese women aged 35-50 years were randomized; analysed tables report 12 per group after non-completion.
  • 27 participants.
  • Running.
  • Work intervals: Five 4-minute running intervals.
  • Recovery: Active recovery running at 60% HRR; approximately 2 minutes based on the 2:1 work:rest ratio.
  • Intensity: Main training at 80-85% HRR after two preparatory weeks.
  • 28 minutes.
  • 5 sessions per week.
  • 10 weeks.
  • Two-arm randomized pre/post exercise intervention comparing HIIT with HIIT plus circuit resistance training.
  • VO2max, Mean 1RM strength, Anthropometrics and body composition, and Lipid profile were tracked.

Outcomes

Body composition

Body mass, BMI, and body-fat percentage improved over time without significant group by time interactions.

Time effects: body mass p = 0.015, BMI p = 0.035, body fat p < 0.001.

Improved

VO2max

VO2max improved over time, but without a significant group by time interaction.

Time effect p < 0.001; no group by time interaction reported.

Improved

Strength

Mean 1RM improved more in the combined HIIT plus resistance group.

Group by time interaction p < 0.001; HCRT post-hoc increase p = 0.001.

Improved

miR-155

HIIT increased miR-155 expression.

Time effect p = 0.001; group by time p = 0.05; HIIT pre-post p = 0.045.

Improved

Lipid profile

Lipid changes differed by group: HCRT lowered total cholesterol and HDL cholesterol, while HIIT lowered triglycerides and LDL cholesterol.

Interactions: TC p = 0.035, TG p < 0.001, LDL-C p = 0.029, HDL-C p = 0.009.

Mixed

Insights

  • For overweight/obese middle-aged women, combining HIIT with resistance training appears more useful for strength than running HIIT alone.
  • Running HIIT may need a fitness screen and gradual ramp because low fitness affected completion.
  • Molecular markers such as miRNAs should be treated as mechanistic context rather than app-facing outcome claims.

Limitations

  • Small sample.
  • No inactive control group.
  • Diet and outside physical activity were not tightly regulated.
  • Menstrual-cycle timing may have influenced miRNA expression.
  • Findings are limited to overweight/obese middle-aged women under supervision.

Safety

  • No explicit adverse events were reported in the article text read.
  • Two HIIT participants were unable to complete the trial because of poor physical fitness.
  • The intervention used two preparatory weeks before the higher-intensity main training block.