# Effects of different training intensities on blood lymphocytes, monocytes and neutrophils in young male athletes

PMID: 35996161
Journal: BMC sports science, medicine & rehabilitation
Published: 2022 Aug 22
Authors: Rhibi F, Abderrahman AB, Prioux J, Clark CCT, Bideau B, Besbes S, Hackney AC, Granacher U, Zouhal H

## Question

Do 8 weeks of running HIIT at 100% versus 110% maximal aerobic velocity produce different aerobic, muscle-damage, inflammatory, and hematological adaptations in young male physical education students?

## Summary

In young active men, 8 weeks of supervised 30 s running intervals improved maximal aerobic velocity. Training at 110% of maximal aerobic velocity improved more than 100%, but the study was small and athlete-specific.

## Population

- Healthy male physical education students assigned to control, 100% MAV HIIT, or 110% MAV HIIT.
- Sample size: 29
- Age: about 21-22 years by group
- Sex: male only
- Fitness level: physically active students/young athletes
- Health status: healthy; screened for contraindications, endocrine disorders, metabolic syndrome, hypertension, and recent injuries

## Methodology

- parallel-group randomized controlled training study
- 8 weeks
- outdoor 400 m tartan track, supervised by laboratory staff
- Randomized and controlled study design.

## Protocol

- Running HIIT at 110% MAV.
- Modality: running.
- Work intervals: 30 s.
- Recovery: 30 s active recovery at 50% MAV; 5 min passive recovery between 2 series.
- Sets or repetitions: 2 series of 8-12 repetitions depending on week.
- Intensity: 110% maximal aerobic velocity for work intervals.
- Session duration: about 44-52 min including 20 min warm-up, inter-series rest, recoveries, and cool-down.
- Frequency: 3 sessions/week with at least 48 h between sessions.
- Program length: 8 weeks; 24 sessions.
- Progression: 2 x 8 reps in week 1, then 9, 10, 11, 10, 12, 12, and 11 reps by week; speeds updated after a week-5 maximal test.
- Running HIIT at 100% MAV.
- Modality: running.
- Work intervals: 30 s.
- Recovery: 30 s active recovery at 50% MAV; 5 min passive recovery between 2 series.
- Sets or repetitions: same 2-series progression as 110% MAV group.
- Intensity: 100% maximal aerobic velocity for work intervals.
- Session duration: about 44-52 min including warm-up, recovery, and cool-down.
- Frequency: 3 sessions/week.
- Program length: 8 weeks.
- Progression: same repetition progression and week-5 speed update as 110% MAV group; non-HIIT control continued compulsory physical education only.

## Outcomes

### MAV
Status: improved
Both HIIT groups improved, with larger improvement after 110% MAV than 100% MAV.

EG100 +5.8%; EG110 +8.9%; group x time p<0.001, eta2=0.61; post-HIIT EG110 vs EG100 p=0.01, eta2=0.05

### Muscle markers
Status: improved
Liver and muscle-damage markers generally decreased; CK decreased only in the 110% group.

ALAT and ASAT lower in both groups; EG110 lower than EG100 post-HIIT for ALAT p=0.04 and ASAT p=0.02; CK decreased only in EG110 p=0.01

### Immune cells
Status: mixed
White blood cells and neutrophils decreased in both HIIT groups; lymphocytes decreased only in the higher-intensity group.

WBC and NE decreased in both exercise groups; LY decreased only in EG110; monocytes unchanged

## Practical Insights

- Thirty-second running intervals can be progressed by adding repetitions across weeks while keeping work and recovery fixed.
- The stronger 110% MAV dose improved aerobic speed more in this active male sample, but it requires individual fitness testing and supervision.
- Blood marker changes were interpreted as adaptation and possible transient immune suppression, so recovery spacing matters.

## Limitations

- Small sample of young active men.
- No soreness or muscle strength outcomes.
- Protocol depends on measured maximal aerobic velocity and track pacing.

## Safety And Adherence

- No testing or training injuries occurred; blood-cell changes included reduced WBC/neutrophils and lymphocytes in the higher-intensity group.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/35996161/) (pubmed)
- [DOI](https://doi.org/10.1186/s13102-022-00550-x) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9396849/) (full text)

## Agent Guidance

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