PMID 41343070

Research
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Acute effects of high-intensity interval training on retinal microvascular circulation in cancer patients and healthy controls: insight from the optical coherence tomography angiography

Wefelnberg MM, Hubert J, Baumann FT, Zubac D

Question

How does an acute cycling HIIT session affect retinal microvascular circulation in cancer patients compared with healthy controls?

Summary

This small prospective study tested an acute cycling HIIT session in young cancer patients receiving treatment and healthy controls. The protocol was medically screened and monitored, produced different acute retinal microvascular responses between groups, and the authors reported no adverse events during recruitment or data collection.

Methodology

  • Twelve young cancer patients and eleven healthy controls completed acute HIIT
  • 23 participants.
  • Stationary cycling.
  • Work intervals: 1 minute.
  • Recovery: 2 minutes at 30% PPO.
  • Intensity: 90% PPO.
  • About 19 minutes for intervals and recoveries.
  • Single acute session.
  • Acute study.
  • Prospective acute interventional comparison study
  • Retinal microvasculature, Exercise capacity, Perceived exertion, and Safety were tracked.

Outcomes

Retina

Deep and superficial retinal OCTA measures showed group-by-time effects.

eta2 0.165-0.473; p<0.01.

Mixed

Optic disc

Optic-disc measures did not show the same group-by-time response.

No significant group-by-time effect reported.

No clear change

Fitness

Cancer patients had lower baseline exercise capacity than controls.

PPO 2.40 +/- 0.59 vs 3.48 +/- 0.34 W/kg; VO2peak 29.4 +/- 6.9 vs 40.3 +/- 3.4 ml/kg/min.

Safety concern

Safety

No adverse events occurred during recruitment or data collection.

No clear change

Insights

  • Relative-intensity cycling HIIT can be completed by carefully screened young cancer patients in a monitored setting.
  • Clinical safety screening matters more than the interval structure for consumer translation.
  • Mechanistic retinal outcomes should not be presented as direct fitness benefits.

Limitations

  • Small sample.
  • Heterogeneous cancer therapies.
  • Acute-only study.
  • OCTA image-quality issues reduced usable data.
  • Limited generalizability beyond young ECOG 0-1 cancer patients.

Safety

  • The authors explicitly reported no adverse events during recruitment or data collection.
  • Medical clearance was required, with stress ECG or ultrasound recommended when needed.
  • One healthy participant withdrew before HIIT; five cancer candidates failed inclusion before the final sample.