# Low-Volume High-Intensity Interval Training in a Gym Setting Improves Cardio-Metabolic and Psychological Health

PMID: 26402859
Journal: PLOS ONE
Published: 2015
Authors: Shepherd SO, Wilson OJ, Taylor AS, Thøgersen-Ntoumani C, Adlan AM, Wagenmakers AJ, Shaw CS

## Question

Can a brief, supervised gym-based HIT program improve cardio-metabolic and psychological health compared with a more time-consuming moderate-intensity continuous training program?

## Summary

In inactive but otherwise healthy adults, 10 weeks of supervised low-volume cycling HIIT improved aerobic fitness, several cardiometabolic markers, body composition, and short-term psychological wellbeing similarly to moderate-intensity continuous training, while requiring less weekly training time and showing better attendance.

## Population

- Healthy inactive adult employees recruited from a university and hospital.
- Sample size: 90
- Age: 18-60 years; mean 42 +/- 11
- Sex: Both sexes
- Fitness level: Inactive, not meeting physical activity guidelines for the preceding year.
- Health status: No known metabolic or cardiovascular disease.

## Methodology

- Randomized controlled trial
- 10 weeks plus 3-month psychological/physical activity follow-up
- University sports centre gym/spinning suite.
- Randomized and controlled study design.

## Protocol

- Low-volume gym HIT.
- Modality: Stationary cycling.
- Work intervals: 15-60 s.
- Recovery: 45-120 s active recovery.
- Sets or repetitions: Repeated sprints; exact count varied.
- Intensity: >90% HRmax; actual average max HR 91 +/- 6% HRmax.
- Session duration: 18-25 min.
- Frequency: 3 sessions/week.
- Program length: 10 weeks.
- Progression: Session interval structure progressed/varied over 10 weeks.
- Moderate-intensity continuous training.
- Modality: Cycling, walking, jogging, or elliptical; supervised cycling sessions plus unsupervised exercise.
- Work intervals: Continuous.
- Sets or repetitions: Continuous 30 min progressing to 45 min.
- Intensity: About 70% HRmax.
- Session duration: 30-45 min plus warm-up/cool-down for supervised sessions.
- Frequency: 3 supervised plus 2 unsupervised sessions/week.
- Program length: 10 weeks.
- Progression: Supervised continuous duration progressed from 30 to 45 min.

## Outcomes

### VO2max
Status: improved
Both HIT and MICT improved relative VO2max by about 8-9% with no group difference.

Main effect of time p<0.001; HIT 32.0 +/- 7.0 to 34.8 +/- 7.1; MICT 31.5 +/- 7.0 to 33.9 +/- 7.5.

### Adherence and time commitment
Status: improved
HIT required less weekly training time and had higher attendance than MICT.

55 +/- 10 vs 128 +/- 44 min/week p<0.001; adherence 83 +/- 14% vs 61 +/- 15% p<0.001.

### Cardiometabolic markers
Status: improved
Body mass, BMI, fat mass, fasting insulin, insulin/glucose AUC measures, insulin sensitivity, total cholesterol, LDL-C, LDL:HDL ratio and HDL improved over time, generally without group differences.

Multiple main effects of time; group differences generally not significant.

### Psychological outcomes
Status: mixed
Health perceptions, affect and subjective vitality improved post-intervention but were not sustained at 3 months; life satisfaction did not change.

## Practical Insights

- A 3-session/week cycling HIIT schedule can reduce time burden while maintaining attendance.
- Heart-rate display may help participants self-adjust intensity.
- Psychological benefits should not be assumed to persist after structured training stops.

## Limitations

- Healthy inactive adults only
- Gym cycling setting limits bodyweight translation
- HIT and MICT differed in planned weekly sessions and time
- Long-term outcomes beyond 3 months were limited

## Safety And Adherence

- Participants were screened with ECG and were supervised with heart-rate monitoring.
- Specific adverse-event counts were not reported.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/26402859/) (pubmed)
- [DOI](https://doi.org/10.1371/journal.pone.0139056) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4581708/) (full text)

## Agent Guidance

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