Intermittent hypoxia training: novel intervention for treating mild cognitive impairment

Purpose: Although intermittent hypoxic training (IHT) has proven effective against various clinical disorders, its impact on mild cognitive impairment (MCI) is unknown. This study was to test if IHT was safe as a novel intervention for treating patients with MCI. Methods: MCI patients (age 69±3) alternately breathed 10% O2 and room-air (each 5 min) for 8 cycles/session, 3 sessions/week for 8 weeks. Before and after IHT, mean arterial pressure (MAP), arterial-O2 saturation (SaO2), cerebral tissue oxygenation (ScO2) and middle cerebral artery flow velocity (VMCA) were assessed, and cognitive performance was tested by mini-mental status exam (MMSE), California verbal learning test-II (CVLT-II), digit span, trail making test-B (TMT-B), and controlled oral word association test (COWAT). Results: Resting MAP fell from 101±3 to 95±3 mmHg (P2increased from 67.9±1.2 to 70.7±1.6% (PMCA(pre vs post: 46.8±3.0 vs 44.2±1.9 cm/s, P=0.21). During the 5th min of hypoxic challenge, SaO2 similarly fell to 70.3±2.9 and 73.8±1.4% pre- and post-IHT, respectively. The hypoxia-induced VMCA increase doubled from 4.5±2.2 before to 9.2±1.8 cm/s after IHT (P2 during 5-min hypoxia remained greater post- vspre-IHT (P Conclusions: IHT can be safely applied to enhance ScO2 and cerebral vasodilation during hypoxia, and potentially to improve short-term memory and concentration ability in MCI patients.