PMID 39012673

Research
All papers

Long-Term Improvement in Hippocampal-Dependent Learning Ability in Healthy, Aged Individuals Following High Intensity Interval Training

Blackmore DG, Schaumberg MA, Ziaei M, Belford S, To XV, O'Keeffe I, Bernard A, Mitchell J, Hume E, Rose GL, Shaw T, York A, Barth M, Cooper EJ, Skinner TL, Nasrallah F, Riek S, Bartlett PF

Question

Does 6 months of supervised HIIT improve hippocampal-dependent learning and related brain and biomarker measures in healthy older adults?

Summary

In healthy adults aged 65-85, a supervised 6-month treadmill HIIT program improved hippocampal-dependent paired-associate learning, with benefits reported up to 5 years after the intervention. HIIT also showed favorable hippocampal volume, connectivity, and biomarker patterns compared with low- and moderate-intensity exercise, but the study involved carefully screened older adults under close supervision.

Methodology

  • Healthy adults aged 65-85 without cognitive impairment who completed the exercise sessions.
  • 151 participants.
  • Treadmill walking or running with speed and incline adjustment.
  • Work intervals: 4 minutes.
  • Recovery: 3 minutes active recovery.
  • Intensity: 85-95% HRpeak during work intervals; 60-70% HRpeak during active recoveries.
  • About 40 minutes including 10-minute warm-up and 5-minute cool-down.
  • 3 sessions per week.
  • 6 months, 72 sessions.
  • Randomized controlled exercise trial with long-term cognitive follow-up
  • CANTAB paired associated learning and other cognitive domains, Brain-region volume and white-matter tract measures by 7T MRI, BDNF, cortisol, growth hormone, beta-hydroxybutyrate, prolactin, and inflammatory markers, and VO2peak and HRpeak from graded exercise testing were tracked.

Outcomes

Main reported result

HIIT significantly improved hippocampal-dependent paired associated learning after 6 months, with retention reported up to 5 years.

Mixed

Main reported result

The cognitive benefit was specific to the hippocampal learning task; other cognitive domains showed little evidence of exercise effects.

Unclear

Main reported result

Right hippocampal volume was stable in HIIT but decreased in low- and moderate-intensity groups at 6 months.

Mixed

Main reported result

Only HIIT showed significant increases in several resting-state connectivity pairs after 6 months.

Unclear

Main reported result

Cortisol and BDNF responses predicted paired-associate-learning improvement in the HIIT group.

Mixed

Insights

  • For screened older adults, 4 x 4 minute HIIT can be delivered with close heart-rate monitoring and professional supervision.
  • The cognitive result supports possible brain-health relevance of HIIT but should not be generalized to unscreened or cognitively impaired users.
  • Long intervention duration and adherence support were central to the protocol.

Limitations

  • Participants were healthy older adults capable of completing a 6-month supervised program.
  • There was no sedentary or non-exercise social control group.
  • The program was highly supervised, limiting translation to unsupervised app use.
  • It is unknown whether cycling, rowing, or bodyweight HIIT would produce similar outcomes.

Safety

  • Participants were medically screened and exercise was supervised; adverse events were not highlighted in the paper.