# Benefits on Hematological and Biochemical Parameters of a High-Intensity Interval Training Program for a Half-Marathon in Recreational Middle-Aged Women Runners

PMID: 35010758
Journal: International journal of environmental research and public health
Published: 2022 Jan 3
Authors: Bonet JB, Javierre C, Guimarães JT, Martins S, Rizo-Roca D, Beleza J, Viscor G, Pagès T, Magalhães J, Torrella JR

## Question

Do HIIT-oriented and moderate continuous half-marathon training programs produce different hematological and biochemical responses in recreational middle-aged women runners?

## Summary

Twenty recreational middle-aged women runners trained for a half-marathon with either a lower-volume HIIT-oriented program or a moderate continuous running program. Both groups completed the race; the HIIT program used less time and distance and showed some smaller post-race muscle-damage and inflammatory marker changes than the moderate program.

## Population

- Twenty healthy female master recreational runners
- Sample size: 20
- Age: 40 +/- 7 years
- Sex: Female
- Fitness level: Recreational runners; VO2max 48.0 +/- 5.6 ml/kg/min
- Health status: Healthy, premenopausal, nonsmoking, injury-free

## Methodology

- Randomized training comparison from a larger trial
- 12 weeks plus half-marathon race follow-up
- Recreational running training and laboratory blood sampling
- Randomized and controlled study design.

## Protocol

- HIIT-oriented half-marathon training.
- Modality: Running intervals, hills, bodyweight circuit, sprints, and long runs.
- Work intervals: Varied: 200 m, 400 m, hills, circuit stations, 50 m sprints.
- Recovery: Varied.
- Sets or repetitions: Three sessions per week.
- Intensity: High-intensity elements; exact target not reported.
- Session duration: Total 33 h 26 min across 12 weeks.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Long run progressed up to 16 km.
- Moderate-intensity continuous half-marathon training.
- Modality: Continuous running, long runs, and weekly 800 m intervals.
- Work intervals: Continuous 40-60 min runs and 800 m intervals.
- Sets or repetitions: Three sessions per week.
- Intensity: Moderate continuous emphasis.
- Session duration: Total 40 h 30 min across 12 weeks.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Long runs progressed up to 25 km.

## Outcomes

### Training load
Status: improved
HIIT used less time and distance than MICT.

33 h 26 min vs 40 h 30 min; 301 km vs 383 km.

### CK
Status: improved
Post-race CK rose in both groups but less in HIIT.

HIIT +63% vs MICT +153%; p=0.043.

### CRP
Status: improved
Post-race CRP rose in both groups but less in HIIT.

Between-group post-race difference p=0.039.

### Safety markers
Status: mixed
No hyponatremia or liver-injury signal was reported, but post-race oxidative and inflammatory stress increased.

## Practical Insights

- Lower-volume interval-oriented training may be feasible for experienced half-marathon runners.
- Race preparation and race completion still produce measurable recovery stress.
- Consumer programming should include recovery, hydration, and runner-readiness constraints.

## Limitations

- Small sample.
- Women-only trained runner population.
- Nutritional data were limited.
- Premenopausal status variability may confound biochemical markers.
- Adverse-event and adherence reporting were limited.

## Safety And Adherence

- Adverse events and dropouts were not explicitly reported.
- Participants were screened as healthy, nonsmoking, premenopausal, medication-free, and injury-free recreational runners.
- All participants appear in final sampling and race analyses; the race increased muscle-damage, inflammatory, and oxidative-stress markers.
- The authors reported no exercise-associated hyponatremia and no liver-injury marker pattern.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/35010758/) (pubmed)
- [DOI](https://doi.org/10.3390/ijerph19010498) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8744745/) (full text)

## Agent Guidance

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