No abstract

This review explores forms of respiratory and autonomic plasticity, and associated outcome measures, that are initiated by exposure to intermittent hypoxia. The review focuses primarily on studies that have been completed in humans and primarily explores the impact of mild intermittent hypoxia on outcome measures. Studies that have explored two forms of respiratory plasticity, progressive augmentation of the hypoxic ventilatory response and long-term facilitation of ventilation and upper airway muscle activity, are initially reviewed. The role these forms of plasticity might have in sleep disordered breathing are also explored. Thereafter, the role of intermittent hypoxia in the initiation of autonomic plasticity is reviewed and the role this form of plasticity has in cardiovascular and hemodynamic responses during and following intermittent hypoxia is addressed. The role of these responses in individuals with sleep disordered breathing and spinal cord injury are subsequently addressed. Ultimately an integrated picture of the respiratory, autonomic and cardiovascular responses to intermittent hypoxia is presented. The goal of the integrated picture is to address the types of responses that one might expect in humans exposed to one-time and repeated daily exposure to mild intermittent hypoxia. This form of intermittent hypoxia is highlighted because of its potential therapeutic impact in promoting functional improvement and recovery in several physiological systems.

Objectives To determine the effect of 7-weeks of resistance training and walking on the apneahypopnea index (AHI) in institutionalized older adults compared to a usual care control group. Design Secondary analysis of data from a randomized controlled-trial. Setting Ten nursing and three assisted living facilities in Arkansas. Participants Institutionalized older adults. Interventions Exercise group (EG) performed supervised resistance training to arm and hip extensors on 3 days a week with additional 2 days a week of light walking. Usual care group (UC) participated in the usual activities provided within their living facility. Measurements 2 nights of polysomnography before and following 7-week intervention. Results Adjusted means in the EG group showed a decrease in AHI from 20.2 (SD±1.3) at baseline to 16.7 (SD±0.9) at 7 weeks. Absolute strength gains were not associated with improved AHI. Conclusion Supervised resistance training and light walking reduced the severity of OSA in institutionalized older adults.