Effects of Intermittent Hypoxia on Cognitive Performance and Quality of Life in Elderly Adults: A Pilot Study

Abstract

Background: Physical exercise has a positive effect on cognitive performance and quality of life (QoL). One reason for this is the upregulation of brain-derived neurotrophic factor, which improves brain plasticity. Intermittent hypoxia promotes first the proliferation of endogenous neuroprogenitors which leads to an increased number of newborn neurons and second the expression of brain-derived neurotrophic factor in the adult hippocampus. Intermittent hypoxia may, therefore, support synaptic plasticity, the process of learning and provoke antidepressant-like effects. Hence, intermittent hypoxia might also lead to improved cognitive functioning and QoL. Objective: This study aims to evaluate to what extent physical activity with preceded intermittent hypoxic training is more effective than solely strength-endurance training on cognitive performance and QoL. Methods: 34 retired people aged between 60 and 70 years were randomly assigned to a control group or intervention group. Contrarily to the control group, which was supplied with a placebo air mixture, the intervention group was supplied with an intermittent hypoxic training prior to a strength-endurance exercise program. The cognitive performance of individuals was examined using the d2 test and the Number Combination Test (ZVT) both before and after the exercise program. We assessed QoL with the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-12) and Pittsburgh Sleep Quality Index (PSQI) and the strength-endurance capacity using the Spring test. Results: Regarding the d2 test, a time × group effect was observed. Speed of cognitive performance in seconds was measured using ZVT. Here, no interaction effect was discovered. An interaction effect was not found in the Physical Component Summary scores (SF-12). Regarding the Mental Component Summary, an interaction effect just failed to become statistically significant. Furthermore, we determined sleep quality with the PSQI. Here, an interaction effect was observed. The analysis of the strength-endurance test revealed no interaction effects. Conclusion: The data of the current study suggest that an additional intermittent hypoxic training combined with physical exercise augments the positive effects of exercise on cognitive performance and QoL in elderly humans.