Sleep and breathing

Physiological Changes in Breathing During Sleep:
– Breathing transitions from wakefulness to sleep due to biological processes.
– Minute ventilation reduces during sleep due to decreased metabolism.
– Rib cage contribution to ventilation increases during NREM sleep.
– Airway resistance increases by about 230% during NREM sleep.
– Arterial blood gases show changes in pCO2, pO2, and SaO2 during sleep.

Sleep Stages and Breathing:
– During NREM sleep, we move through three stages, each deeper than the last.
– Minute ventilation decreases by 13% in the second NREM stage and by 15% in the third.
– Rib cage contributes more to ventilation during NREM sleep.
– Upper airway resistance increases significantly during NREM sleep.
– Changes in arterial blood gases occur during NREM sleep.
– Breathing irregularities occur in REM sleep, not controlled by chemoreceptors.
– Minute ventilation decreases in REM sleep compared to wakefulness.
– Intercostal muscle activity decreases in REM sleep.
– Upper airway resistance is highest during REM sleep.
– Changes in arterial blood gases occur during REM sleep.

Effects of Altitude on Sleep and Breathing:
– Disruptions in sleep at high altitudes are linked to changes in respiratory rhythm.
– Variations in sleep time occur at higher altitudes.
– Subjects at high altitudes experience more frequent arousals and diminished deep sleep stages.
– Poorer sleep quality at high altitudes due to more frequent awakenings.
– Changes in altitude affect sleep time and quality, leading to more arousals and less deep sleep stages.

Sleep Apnea:
– Common sleep disorder characterized by pauses in breathing.
– Can lead to serious health issues and is linked to high blood pressure.
– Diagnosis involves sleep study evaluation, monitoring breathing patterns, assessment of oxygen levels, and medical history review.
– Risk factors include obesity, age over 40, family history of apnea, large neck circumference, and alcohol and sedative use.
– Management options include Continuous Positive Airway Pressure (CPAP), lifestyle changes, oral appliances, surgery in severe cases, and regular follow-ups for monitoring.

Effects and Management of Sleep Apnea:
– Effects include daytime fatigue, poor concentration, increased risk of accidents, depression, irritability, and impacts on overall quality of life.