# Physiological responses to acute resistance high-intensity interval exercise and cycling high-intensity interval exercise in healthy active men

PMID: 36160857
Journal: Frontiers in Physiology
Published: 2022
Authors: Mao J, Wang T, Zhang L, Li Q, Bo S

## Question

How do acute cycling HIIT and resistance-exercise HIIT differ in physiological, metabolic, hormonal, autonomic, and perceptual responses in healthy active men?

## Summary

In healthy active young men, an acute cycling HIIT session produced higher oxygen consumption and total energy expenditure than a resistance-squat HIIT session, while resistance HIIT produced greater glycolytic contribution and post-exercise lactate. Heart rate, testosterone, cortisol, HRV, and RPE were broadly similar. This is acute physiology evidence, not training-adaptation evidence.

## Population

- Healthy active men completing both cycling and resistance HIIT conditions.
- Sample size: 12
- Age: 21.9 +/- 2.6 years
- Sex: Male
- Fitness level: Healthy active; VO2max 45.9 +/- 5.1 mL/kg/min
- Health status: Healthy active young adults

## Methodology

- Randomized crossover acute exercise study
- Acute sessions with at least 1 week washout
- Laboratory exercise testing
- Randomized and controlled study design.

## Protocol

- Cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 60 seconds.
- Recovery: 60 seconds active recovery.
- Sets or repetitions: 10 intervals.
- Intensity: 90% peak power output for work bouts; 25% peak power output for recovery.
- Session duration: 19-minute intervention after warm-up.
- Frequency: One acute session.
- Program length: Acute crossover condition.
- Progression: No progression.
- Resistance HIIT.
- Modality: Barbell back squat intervals.
- Work intervals: 60 seconds.
- Recovery: 60 seconds passive standing/unloaded recovery.
- Sets or repetitions: 10 intervals, up to 30 reps per interval.
- Intensity: 20% body-weight barbell load, 1-second eccentric and fast concentric tempo.
- Session duration: 19-minute intervention after warm-up.
- Frequency: One acute session.
- Program length: Acute crossover condition.
- Progression: No progression.

## Outcomes

### VO2
Status: improved
Cycling HIIT elicited higher oxygen consumption than resistance HIIT.

VO2peak 38.9 +/- 4.0 vs 36.4 +/- 4.4, p=0.022; VO2mean 29.6 vs 25.1, p<0.001.

### Energy expenditure
Status: mixed
Cycling HIIT had higher total and aerobic energy expenditure, while resistance HIIT had higher anaerobic glycolytic energy.

Aerobic EE 205.8 vs 174.4 kcal, p<0.001; anaerobic glycolytic EE 9.0 vs 11.7 kcal, p=0.002; total EE 214.7 vs 186.1 kcal, p=0.001.

### Heart rate
Status: no clear change
Peak and mean HR were not significantly different between modalities.

HRpeak 178.0 vs 182.4 bpm, p=0.218; HRpeak percent 91.8 vs 93.9, p=0.216; HRmean p=0.070.

### Hormones and HRV
Status: no clear change
Testosterone, cortisol, HRV, and RPE did not differ clearly between conditions.

Abstract and results report no significant between-condition differences in testosterone, cortisol, HRV, and RPE.

## Practical Insights

- Cycling and resistance HIIT can produce similar HR strain while stressing different metabolic pathways.
- Squat-based resistance HIIT may create higher glycolytic/lactate stress at lower total energy expenditure.
- Acute equivalence in HR or RPE should not be interpreted as equivalent training adaptation.

## Limitations

- Small sample of 12 active men.
- Acute crossover design only.
- No women, sedentary adults, or clinical participants.
- Laboratory outcomes do not establish long-term adaptations.
- Resistance HIIT used barbell squats with researcher assistance, limiting home translation.

## Safety And Adherence

- All 12 participants completed both acute sessions.
- No adverse events were reported in the extracted text.
- Barbell squat intervals required researcher assistance for safe bar placement/removal.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/36160857/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2022.986920) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9500456/) (full text)

## Agent Guidance

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