Freediving as a natural human model to study hippocampal adaptability to hypoxia and episodic memory
Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom
Julia Micaux1, Clément Poiret1, Jingwen Zhao1, Aya El Hajj3, Moragne Tillenon4, Franck Mauconduit2, Fawzi Boumezbeur2, Catherine Chiron1, Marion Noulhiane1; 1UNIACT, InDev 1141, NeuroSpin, CEA-SACLAY F-91191, Gif-sur-Yvette, France, 2BAOBAB, NeuroSpin, CNRS, CEA-SACLAY F-91191, Gif-sur-Yvette, France, 3Sport Sciences Department, Univ Rouen Normandie, CETAPS, Rouen, France, 4Paris Brain Institute, Centre d’Investigation Clinique ; APHP, Département des Maladies du Système nerveux, Hôpital Pitié-Salpêtrière, F-75013, Paris, France
Accidental hypoxia has detrimental effects on the brain, particularly on the hippocampal subfields (HS), which is highly sensitive to oxygen deprivation and play a crucial role for episodic memory. This raises the question: can freediving, which involves prolonged breath-holding, cause anatomical changes in the HS and impair memory? The aim was to clarify the impact of freediving on HS anatomy and memory. Seventeen freedivers were assessed before and after seven months of training, alongside a control group of twenty non-freedivers. An MRI segmentation tool HSF(c) was used to measure HS volumes; and a pattern separation task – which required distinguishing between identical, similar, and new items –assessed episodic memory. Our results showed no significant differences in HS volumes or memory performance between the two groups, both pre- and post-training. Additionally, our results confirmed that freedivers performed similarly to controls in the PS task. Both groups were more accurate with identical items than with similar ones (p<0.001) and were less accurate with similar items compared to new ones (p<0.001), reflecting the cognitive demands of distinguishing similar items. Overall, our findings suggest that repeated voluntary hypoxic exposure during freediving does not impair hippocampal anatomy or memory. Freedivers maintained comparable memory performance to the control group, indicating no adverse effects. Moreover, this study highlight the potential benefits of regular physical activity, even in hypoxic conditions, for promoting hippocampal adaptability. In summary, freediving offers a valuable model for investigating how repeated voluntary hypoxia induces cerebral adaptability in healthy individuals.
Topic Area: LONG-TERM MEMORY: Episodic