Comparison of cerebrovascular reactivity recovery following high-intensity interval training and moderate-intensity continuous training
Question
How long do cerebrovascular reactivity measures remain altered after acute HIIT compared with moderate continuous exercise and rest?
Summary
In nine young adults, a single cycling HIIT session temporarily reduced cerebrovascular reactivity to high carbon dioxide for about one hour, with recovery by two hours. Moderate continuous cycling produced smaller or limited changes, and quiet rest was stable.
Methodology
- Nine healthy young adults from a university setting.
- 9 participants.
- Cycle ergometer.
- Work intervals: 1 minute.
- Recovery: Active cycling recovery between intervals; exact duration not clearly reported.
- Intensity: 85-90% heart-rate reserve.
- 25 minutes.
- Single acute session.
- One session.
- Randomized acute repeated-measures laboratory comparison
- Hypercapnic CVR slopes, Hypocapnic CVR slopes, and Cardiovascular response were tracked.
Outcomes
Hypercapnic CVR
HIIT attenuated MCA/PCA hypercapnic slopes immediately and at 1 hour, with recovery by 2 hours.
At least 37% reductions; all p<0.018 for post-HIIT changes.
Hypocapnic CVR
Hypocapnic slopes did not differ by condition.
All p>0.310.
MICT CVR
MICT produced limited decreases in relative hypercapnic MCA slope but not the broader HIIT pattern.
Relative MCA slope decreased 20% at hour 0 and 16% at hour 1.
Insights
- A two-hour recovery buffer may be adequate before CVR testing after HIIT in healthy young adults.
- HIIT and MICT should not be treated as interchangeable when acute cerebrovascular reactivity is the outcome.
Limitations
- Very small sample.
- TCD velocity assumes stable vessel diameter.
- VO2max was not measured for prescription.
- Healthy young adults limit generalizability.
Safety
- The article did not report adverse events.
- Participants were medically screened by history and monitored with ECG, blood pressure, PETCO2, TCD, and gas analysis during supervised laboratory testing.