# Effects of high-intensity interval training in a cold environment on arterial stiffness and cerebral hemodynamics in sedentary Chinese college female students post-COVID-19

PMID: 39563778
Journal: Frontiers in Neurology
Published: 2024 Nov 5
Authors: Chen X, Hu N, Han H, Cai G, Qin Y

## Question

Does short-term HIIT in a cold environment improve arterial stiffness and cerebral hemodynamics in sedentary female college students post-COVID-19?

## Summary

In sedentary young Chinese women after COVID-19, one week of twice-daily supervised treadmill HIIT improved several vascular, balance, and brain oxygenation measures, especially when performed in a 14 C cold environment. No adverse events were reported, but the trial was very short and highly specific.

## Population

- 36 sedentary Chinese female college students post-COVID-19.
- Sample size: 36
- Age: 19-26 years
- Sex: Female
- Fitness level: Sedentary
- Health status: Mild/moderate post-COVID symptoms

## Methodology

- Randomized controlled trial with room-temperature exercise, cold-environment exercise, and sedentary control
- 1 week
- Treadmill exercise in controlled room-temperature or cold environment
- Randomized and controlled study design.

## Protocol

- Cold-environment treadmill HIIT.
- Modality: Treadmill brisk sprint intervals at 14 C.
- Work intervals: 4 min.
- Recovery: 4 min active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: 75-80% peak HR, Borg RPE 15-18.
- Session duration: About 47 min including warm-up/rest/cool-down.
- Frequency: 2 sessions/day for 1 week.
- Program length: 1 week.
- Progression: No progression.
- Room-temperature HIIT.
- Modality: Treadmill brisk sprint intervals at 22 C.
- Work intervals: 4 min.
- Recovery: 4 min active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: 75-80% peak HR, Borg RPE 15-18.
- Session duration: About 47 min including warm-up/rest/cool-down.
- Frequency: 2 sessions/day for 1 week.
- Program length: 1 week.
- Progression: No progression.

## Outcomes

### baPWV
Status: improved
Cold-environment HIIT reduced arterial stiffness more than room-temperature HIIT or control.

Abstract reported about 11% baPWV decrease in CE; RE did not significantly change baPWV.

### Blood pressure
Status: mixed
Exercise groups reduced SBP while control SBP and pulse pressure increased.

Post-test SBP and pulse pressure differed across groups; control pulse pressure higher than CE/RE.

### Cerebral hemodynamics
Status: improved
HbO and HbT increased during balance tasks in exercise groups, especially CE.

CE showed greater regional HbO/HbT increases than RE and control in several frontal/motor regions.

### Safety
Status: no clear change
No adverse events were reported.

Article states no adverse events.

## Practical Insights

- Cold exposure is an intervention modifier, not a default app recommendation.
- 4 x 4 min HIIT requires substantial session time and monitoring.
- Short-term physiological improvements should be framed as preliminary.

## Limitations

- Small sample.
- Only sedentary Chinese female college students post-COVID.
- One-week intervention only.
- No long-term follow-up.
- No multiple cold-temperature gradients.
- Many outcomes were surrogate physiological measures.

## Safety And Adherence

- No adverse events were reported.
- Intensity was monitored with HR and RPE under coach supervision.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/39563778/) (pubmed)
- [DOI](https://doi.org/10.3389/fneur.2024.1466549) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11573531/) (full text)

## Agent Guidance

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