# 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

PMID: 38812051
Journal: BMC Sports Science, Medicine & Rehabilitation
Published: 2024 May 29
Authors: 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.

## Population

- Twenty-seven overweight or obese women aged 35-50 years were randomized; analysed tables report 12 per group after non-completion.
- Sample size: 27
- Age: 35-50 years
- Sex: Women only
- Health status: Overweight or obese middle-aged women.

## Methodology

- Two-arm randomized pre/post exercise intervention comparing HIIT with HIIT plus circuit resistance training.
- 10 weeks.
- Supervised afternoon exercise sessions in an indoor gymnasium.
- Randomized and controlled study design.

## Protocol

- Running HIIT.
- Modality: 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.
- Sets or repetitions: 5 intervals per session.
- Intensity: Main training at 80-85% HRR after two preparatory weeks.
- Session duration: 28 minutes.
- Frequency: 5 sessions per week.
- Program length: 10 weeks.
- Progression: Weeks 1-2 preparatory lower intensity; weeks 3-10 80-85% HRR.
- HIIT plus circuit resistance training.
- Modality: Running HIIT plus machine-based circuit resistance training.
- Work intervals: HIIT sessions used the same interval structure as the HIIT group; resistance sessions used 10-12 repetitions per exercise.
- Recovery: HIIT active recovery at 60% HRR; resistance sessions used 90 seconds between sets and 120 seconds between stations.
- Sets or repetitions: Three sets of 10-12 repetitions across leg press, knee extension/flexion, calf raise, bench press/inclined bench press, seated row, and lat pull-down.
- Intensity: HIIT 80-85% HRR during main weeks; resistance 50-60% 1RM in weeks 1-2 and 65-80% 1RM in weeks 3-10.
- Frequency: 3 HIIT sessions and 2 resistance circuit sessions per week.
- Program length: 10 weeks.
- Progression: Resistance intensity increased from 50-60% 1RM to 65-80% 1RM after the preparatory period.

## Outcomes

### Body composition
Status: improved
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.

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

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

### Strength
Status: improved
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.

### miR-155
Status: improved
HIIT increased miR-155 expression.

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

### Lipid profile
Status: mixed
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.

## Practical 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 And Adherence

- 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.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/38812051/) (pubmed)
- [DOI](https://doi.org/10.1186/s13102-024-00904-7) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11137892/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.