Acute effects of high-intensity interval training and moderate-intensity continuous training on executive functions in healthy older adults
Question
What are the acute effects of a single HIIT session versus a single moderate continuous training session on executive-function performance in healthy older adults?
Summary
In healthy older adults, one supervised cycling HIIT session and one moderate continuous cycling session both improved several Stroop executive-function response-time outcomes shortly after exercise. HIIT appeared to have a more sustained benefit for task switching 45 minutes after exercise.
Methodology
- Healthy community-dwelling older adults recruited from Acadia Active Aging and Active for Life.
- 25 participants.
- Cycle ergometer.
- Work intervals: 15 seconds at 100% peak power output.
- Recovery: 15 seconds passive recovery at 0% peak power output, with 5 minutes passive recovery between sets.
- Intensity: 100% peak power output during work intervals.
- 5-minute warm-up at 25% peak power output, two 20-minute interval sets separated by 5 minutes passive recovery, followed by recovery cycling at 25% peak power output.
- Single acute session.
- One laboratory visit in a crossover design.
- Randomized counterbalanced crossover acute exercise study comparing one HIIT session with one MICT session.
- Stroop naming response time, Stroop inhibition response time, Stroop switching response time, and Safety and completion were tracked.
Outcomes
Study completion
All participants completed the crossover study.
25/25 completed.
Stroop inhibition response time
Both HIIT and MICT improved inhibition response time immediately and at 45 minutes, with no significant HIIT-versus-MICT difference.
Approximate reductions: HIIT 77.6 ms immediate and 80.7 ms at 45 minutes; MICT 68.7 ms immediate and 66.0 ms at 45 minutes. HIIT vs MICT p = 0.228 immediate and p = 0.634 at 45 minutes.
Stroop switching response time
Both protocols improved switching response time immediately; HIIT had a larger sustained switching reduction at 45 minutes.
HIIT advantage over MICT at 45 minutes was 73.6 ms, p = 0.019.
Stroop naming response time
The article reports significant HIIT naming response-time reductions immediately and at 45 minutes; the discussion indicates both protocols improved naming.
HIIT reduction about 70 ms versus baseline; immediate p < 0.001 and 45-minute p = 0.005.
Insights
- A single bout of exercise can transiently improve executive-function task performance in screened older adults.
- For cognitive-flexibility outcomes, HIIT may have a longer-lasting acute effect than moderate continuous exercise.
- The tested protocol is equipment-based and demanding; game-based bodyweight adaptations should be treated as hypotheses, not direct replications.
Limitations
- Small sample size.
- Only acute effects were tested, so durability beyond 45 minutes is unknown.
- Participants were healthy and cognitively intact, limiting generalization to clinical or cognitively impaired populations.
- The study did not measure mechanistic biomarkers.
- Energy expenditure during HIIT rest intervals was not directly measured.
- Baseline cognitive testing was not performed immediately before each exercise condition.
Safety
- Participants were screened for medical and musculoskeletal risks.
- Maximal exercise testing used ECG monitoring.
- All 25 participants completed the study; no adverse-event details were reported in the paper.