# Ratings of Perceived Exertion and Self-reported Mood State in Response to High Intensity Interval Training. A Crossover Study on the Effect of Chronotype

PMID: 28769855
Journal: Frontiers in Psychology
Published: 2017
Authors: Vitale JA, La Torre A, Baldassarre R, Piacentini MF, Bonato M

## Question

Does chronotype affect perceived exertion and mood responses to morning versus evening high-intensity interval exercise?

## Summary

In active male students, an acute 4 x 4 min HIIT session felt harder and affected fatigue/vigor differently when performed at a time that did not match chronotype, especially for evening types training in the morning.

## Population

- Healthy physically active male sport-science college students with morning or evening chronotype
- Sample size: 23
- Age: At least 18 years; group mean age not clearly extracted
- Sex: 23 men
- Fitness level: Physically active at least 6 h/week
- Health status: Healthy, non-smoking, no medications or medical contraindications

## Methodology

- Randomized crossover acute exercise study
- Two acute sessions separated by 7 days
- Outdoor 400 m track in morning and evening testing sessions
- Randomized and controlled study design.

## Protocol

- 4 x 4 min high-intensity interval exercise.
- Modality: Track running.
- Work intervals: 4 min.
- Recovery: 3 min active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: 90-95% HRpeak during work; 50-60% HRpeak during active recovery.
- Session duration: 10 min warm-up, 25 min interval set, 3 min cool-down.
- Frequency: Two acute sessions.
- Program length: Crossover visits over 4 weeks.
- Progression: No progression; same session performed morning and evening.
- Time-of-day crossover.
- Modality: Same running HIIT session at alternate time of day.
- Work intervals: 4 min.
- Recovery: 3 min active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: 90-95% HRpeak.
- Session duration: Same as intervention.
- Frequency: One morning and one evening session.
- Program length: 7-day recovery between sessions.
- Progression: Randomized order.

## Outcomes

### Morning RPE
Status: worse/safety concern
Evening types reported higher exertion before and after morning HIIT than morning types.

Before morning: E-types 2.4 +/- 0.9 vs M-types 0.3 +/- 0.3, p = 0.002; 30 min post morning: 6.0 +/- 1.1 vs 4.5 +/- 2.1, p = 0.042

### Chronotype mismatch
Status: mixed
Participants reported higher pre-session RPE when training away from their preferred time.

M-types evening vs morning pre-RPE p = 0.0107; E-types morning vs evening pre-RPE p = 0.008

### Mood
Status: mixed
Fatigue, vigor, and energy index varied by chronotype and timing, while several mood subscales did not.

Morning HIIE showed chronotype effects for fatigue, vigor, and EI at PRE and POST24; evening HIIE interaction at POST12 for fatigue, vigor, and EI

### Tolerability
Status: no clear change
All participants completed both sessions without reported complications.

No dizziness, lightheadedness, or nausea reported

## Practical Insights

- Scheduling HIIT near a user's preferred time of day may reduce perceived burden.
- Evening chronotypes may need extra ramp-up or lower initial demands for morning HIIT.
- A 4 x 4 min session was tolerated by active young men in field conditions.

## Limitations

- Small sample
- Men only
- Physically active sport-science students
- Acute crossover, not a training adaptation study
- No power calculation

## Safety And Adherence

- All participants completed sessions without dizziness, lightheadedness, nausea, or other complications.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/28769855/) (pubmed)
- [DOI](https://doi.org/10.3389/fpsyg.2017.01232) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5514349/) (full text)

## Agent Guidance

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