# High intensity interval training in the heat enhances exercise-induced lipid peroxidation, but prevents protein oxidation in physically active men

PMID: 27227083
Journal: European Journal of Sport Science
Published: 2016
Authors: Souza-Silva AA, Moreira E, de Melo-Marins D, Schöler CM, de Bittencourt PI Jr, Laitano O

## Question

Does performing a short cycling HIIT program in heat, compared with a temperate environment, change exercise-induced lipid and protein oxidation and performance markers?

## Summary

In young physically active men, four weeks of supervised cycling HIIT in a hot room increased peak power output but changed oxidative-stress responses differently than the same training in temperate conditions.

## Population

- Young healthy physically active heat-acclimatized men.
- Sample size: 16
- Age: 23 +/- 2 years
- Sex: Male
- Fitness level: Recreationally active
- Health status: Healthy

## Methodology

- Randomized two-group pre-post training study
- 4 weeks
- Laboratory cycle ergometer sessions in controlled environmental chambers
- Randomized and controlled study design.

## Protocol

- Heat cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 60 s at peak power output.
- Recovery: 75 s active recovery at 30 W.
- Sets or repetitions: 4-7.
- Intensity: Peak power output.
- Session duration: About 10.75-17.5 min including warm-up.
- Frequency: 3 sessions/week.
- Program length: 4 weeks.
- Progression: Add one interval each week.
- Temperate cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 60 s at peak power output.
- Recovery: 75 s active recovery at 30 W.
- Sets or repetitions: 4-7.
- Intensity: Peak power output.
- Session duration: About 10.75-17.5 min including warm-up.
- Frequency: 3 sessions/week.
- Program length: 4 weeks.
- Progression: Add one interval each week.

## Outcomes

### Peak power
Status: improved
Peak power improved in the heat group but not the temperate group.

Heat group p=0.026.

### Oxidative stress
Status: mixed
Heat increased lipid peroxidation while temperate HIIT increased protein carbonyls after acute exercise.

Heat TBARS p=0.0177; control protein carbonyls p=0.0316.

## Practical Insights

- Heat makes HIIT a different physiological stimulus and should be treated as an added load.
- The interval structure is simple but intensity requires a peak-power test.

## Limitations

- Small all-male sample
- Heat-acclimatized participants only
- No direct thermal strain measures during training
- Biomarker outcomes

## Safety And Adherence

- No adverse events were reported.
- Sessions were supervised by at least one research team member, environmental conditions were monitored, and hydration before incremental testing was standardized.
- Dropout/adherence were not reported in detail, but the text indicates both groups completed the same 12-session volume.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/27227083/) (pubmed)
- [DOI](https://doi.org/10.1080/17461391.2016.1185090) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861192/) (full text)

## Agent Guidance

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