# Comparative effects of high-intensity interval training at low and moderate altitudes on 5000-m performance and perceptual responses: A randomized controlled trial

PMID: 41777799
Journal: Journal of exercise science and fitness
Published: 2026 Apr
Authors: Fentaw S, Tadesse T, Birhanu Z

## Question

Does 8 weeks of 4 x 4 min HIIT performed at low altitude versus moderate altitude differently affect 5000 m performance, pacing, and RPE in moderate-altitude resident runners?

## Summary

Moderate-altitude resident distance runners improved 5000 m time, pacing speed, and perceived exertion after adding 4 x 4 min running HIIT twice weekly for 8 weeks. Training at low altitude appeared to produce somewhat larger pacing and RPE benefits than the same structure at moderate altitude.

## Population

- Moderate-altitude resident trained distance runners
- Sample size: 42
- Age: 22.2 +/- 4.3 years
- Sex: 23 men and 19 women
- Fitness level: Trained regional-level endurance runners
- Health status: Healthy enough for competition; recent illness/injury and anaemia excluded

## Methodology

- Randomized controlled field trial
- 8 weeks
- Outdoor track and altitude field-training sites in Ethiopia
- Randomized and controlled study design.

## Protocol

- HIIT at low or moderate altitude.
- Modality: Running.
- Work intervals: 4 min at 100% vVO2max.
- Recovery: 3 min active recovery at 70% vVO2max.
- Sets or repetitions: 4.
- Intensity: 100% vVO2max work; 70% vVO2max recovery.
- Session duration: About 40 min including warm-up and cool-down.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.
- Progression: No interval progression; venue-specific vVO2max was used.
- Usual training control.
- Modality: Distance running.
- Intensity: Usual macrocycle training.
- Program length: 8 weeks.
- Progression: Control group continued usual training at about 2850 m.

## Outcomes

### 5000 m time
Status: improved
Both HIIT altitude groups improved 5000 m time.

HIIT1220m delta 20.1 +/- 23.7 s, p=0.007; HIIT2850m delta 16.7 +/- 25.9 s, p=0.003.

### Pacing speed
Status: improved
HIIT groups improved key kilometer speeds versus control, especially first and fifth kilometers.

Significant group-by-time interaction in all km segments; group effects at 1st km p=0.034 and 5th km p=0.044.

### RPE
Status: improved
Runners reported lower race RPE after HIIT, with greater changes in the low-altitude group.

RPE sensitivity analysis reported large observed effects; exact values in supplemental table.

### Altitude comparison
Status: mixed
Low-altitude HIIT generally produced larger pacing and perceptual changes, but the study was small and field-based.

## Practical Insights

- A 4 x 4 min running HIIT protocol can be integrated twice weekly into a runner macrocycle.
- For moderate-altitude runners, low-altitude quality sessions may allow better pace and RPE outcomes.

## Limitations

- Athlete-only sample
- Altitude-specific logistics
- Small final sample
- No direct heart-rate/lactate/ventilation monitoring
- Outdoor environmental variability

## Safety And Adherence

- No adverse events were described in the extracted article text.
- Six participants were excluded from final analysis for adherence or posttest missingness.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/41777799/) (pubmed)
- [DOI](https://doi.org/10.1016/j.jesf.2026.200460) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12950428/) (full text)

## Agent Guidance

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