Introduction
Sleep is a biological function that is as essential as a balanced diet for a good quality of life. It is a complex phenomenon that is much more than a decrease in consciousness. In 1968, researchers Rechtehaffen and Kales explained sleep and its effects on various diseases and recommended the basic sleep staging rules.
Regular sleep is categorized into two stages: rapid eye movements (REM) and non-rapid eye movements (NREM) which are distinguished based on diagnostic tests such as electromyogram, electroencephalogram (EEG), and electrooculogram (EOG). The proper function of sleep has yet to be entirely understood; however, its physiological consequences are known. Sleep affects temperature regulation and the gastrointestinal, respiratory, immune, autonomic, nervous, and other body systems.
What Are the Common Sleep Disorders That Affect Breathing?
Sleep-related breathing disorders are conditions that cause difficulty in respiration during sleep, including sleep apnea and chronic snoring. Medical conditions, lifestyle habits, or neurological disorders can cause these. Some disorders may have a minimal health impact, while others can cause serious consequences due to disturbed sleep and the imbalance of oxygen and carbon dioxide in the blood. The American Academy of Sleep Medicine (AASM) has recognized several types and subtypes of sleep-related breathing disorders. Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are highly prevalent and the most common sleep disorders related to breathing.
Obstructive Sleep Apnea: It is a condition in which the airway repeatedly collapses during sleep due to partial or complete upper airway obstruction. This leads to lapses in breathing and affects sleep and oxygen levels.
COPD: It is sometimes called emphysema or chronic bronchitis and is a lung disorder that causes restricted airflow and breathing problems. It is the leading cause of morbidity and mortality and can be complicated by sleep disorders.
Insomnia: It is a common sleep disorder characterized by difficulty falling asleep or not getting quality sleep. It leads to low energy, irritability, and depressed mood, thus affecting work performance and daily activities.
Sleep-Related Hypo-Ventilation: It is a condition in which carbon dioxide levels in the blood are elevated during sleep. It occurs due to a lack of air moving in and out of the lungs. It is usually seen in patients with pulmonary hypertension, COPD, and nervous system disorders.
Restless Legs Syndrome: This neurological disorder, also known as Willis-Ekbom disease, causes uncomfortable or unpleasant sensations in the legs and an irresistible urge for movement. It disrupts sleep or makes it difficult to fall asleep, resulting in mood changes, exhaustion, fatigue, depression, anxiety (feelings of fear, tension, or worried thoughts), etc.
What Is the Association Between Sleep Disorders and Respiratory Health?
Sleep is essential for various bodily functions, including respiration and overall health and well-being. However, sleep disorders can disrupt this balance and affect breathing patterns, thus causing severe respiratory issues or exacerbating existing conditions. On the other hand, upper and lower obstructive lung diseases can disrupt sleep and can cause sleep-related breathing disorders.
Both long and short sleep durations are known to be associated with dyspnea and cough. Studies have shown that wheezing, coughing, and difficulty breathing are the primary complaints, mainly related to cardiopulmonary diseases. Sleep disorders are primarily prevalent in asthma patients or patients with poor asthma control. Fragmented sleep can also cause daytime sleepiness and fatigue or affect cognitive function.
What Is the Role of Sleep Disorders in Exacerbating Chronic Respiratory Conditions?
Sleep disorders can significantly exacerbate chronic respiratory conditions and create a vicious cycle where each condition may worsen the other. Sleep disorders can cause increased systemic inflammation in the tissues, thus exacerbating respiratory disorders. Reduced sleep can impair immune function and make patients more susceptible to pulmonary infections. Poor sleep quality or frequent awakenings at night can worsen asthma symptoms.
Chronic insomnia can worsen the symptoms of chronic obstructive pulmonary disease, leading to increased coughing and breathing difficulty. Intermittent hypoxia (low oxygen levels) in conditions such as obstructive sleep apnea can increase sympathetic nervous system activity and blood pressure, hence exacerbating respiratory and cardiovascular diseases.
Obesity (abnormal accumulation of fat in the body) or being overweight is a common condition these days that affects sleep and also increases the risk of developing respiratory disorders. It occurs due to extra fat around the neck, chest, and abdomen, making it difficult to breathe deeply and expand the lungs. It obstructs airflow and causes increased airway hyperresponsiveness, thus affecting sleep and also contributing to respiratory infections, OSA, and pulmonary hypertension (high blood pressure affecting both the lungs and the heart).
How Can Sleep Disorders Be Managed to Improve Respiratory Health?
Lifestyle modifications, such as eating a balanced diet, exercising regularly, avoiding smoking and alcohol, and addressing obesity, can improve sleep and prevent various health complications.
Taking the prescribed medications regularly can keep chronic respiratory diseases under control and reduce the impact of sleep disorders.
Continuous positive airway pressure (CPAP) therapy can effectively treat obstructive sleep apnea and improve the outcomes in patients with chronic respiratory disorders. It is the gold standard treatment for managing OSA, which keeps the airway open during sleep and improves oxygenation.
Cognitive behavioral therapy (CBT) can be beneficial for patients with sleep disorders. It improves sleep quality and prevents its adverse effects on respiration.
Regular monitoring and frequent health check-ups for patients with respiratory diseases and sleep disorders can ensure these conditions are effectively managed.
Conclusion
Sleep is an essential requirement for physical and mental health and overall well-being. According to the National Sleep Foundation, adults require about seven to nine hours of sleep each night; however, most individuals do not get enough, leading to potential consequences or chronic health problems. Sleep disorders can significantly affect respiratory health due to disruptions in breathing patterns during sleep.
A considerable association between sleep and respiratory disorders results in sleep effects on broncho-reactivity, mucous retention, and other breathing mechanisms. Diagnosing respiratory sleep disorders based on clinical features alone is limited, and despite advancements in diagnostic standards, several limitations have yet to be addressed. However, certain lifestyle changes and appropriate management of sleep disorders are essential for maintaining respiratory health and minimizing the risk of complications.