Slow deep breathing techniques are some of the oldest and simplest techniques demonstrated to have a variety of therapeutic effects on the body and mind.
Slow Deep Breathing
Slow deep breathing techniques are some of the oldest and simplest techniques demonstrated to have a variety of therapeutic effects on the body and mind. The growing literature on the effects of slow breathing reveal benefits for stress, affective mood disorder, asthma, and pain, however, the literature on its effects on insomnia is minimal. Slower respiration corresponds to higher cardiorespiratory synchronization which as discussed, may promote parasympathetic tone. Slow, deep, regular breathing may attenuate the sympathetic component of hyper-arousal largely brought about by the frenetic nature of modern life which may cause insomnia. Deeper breathing has been shown to result in stronger sympathoinhibition. In contrast, irregular and fast breathing have been shown to result in sympathetic excitation. There is empirical support that breathing at a frequency of 0.1 Hz is the most effective rate to combat insomnia as this rate initiates CS and has been demonstrated to enhance parasympathetic activity. Practicing the 0.1 Hz rate (6 breathes per min) before sleep was shown to improve sleep onset latency and quality in insomniacs and enhance the stability of their sleep pattern. Thus, we suggest 0.1 Hz as the optimal frequency for a slow breathing technique.
The efficacy of slow breathing techniques has been recognized by the military which use such techniques during combat situations to regain composure and reduce stress. Regular practice of a slow breathing technique overtime may provide long term correction of sympathetic over-arousal. In addition, slow, deep breathing has been shown to result in melatonin production which not only promotes relaxation but is an essential sleep-inducing hormone which promotes parasympathetic tone and inhibits sympathetic tone. Exogenous administration of melatonin can however lead to next-day drowsiness, headache, and/or dizziness. Melatonin levels are lower in insomniacs and much lower in long-term insomniacs, suggesting that the longer a sleep disorder exists, the more severe it gets. Sleep deprivation can result in increased sympathetic tone. This supports our view of a vicious cycle of worsening sleep deprivation; as sleep deprivation worsens stress, this may lead to further sympathetic hyper-arousal further worsening a sleep disorder.
Although out of the scope of this article, another mechanism by which we suggest slow deep breathing may treat insomnia has recently gained significant support, neural entrainment. Recent findings suggest that nasal respiration may act as a global organizer of neural oscillatory activity throughout the brain. By modulating global network oscillations, respiration may exert control over cortical excitability. Such entrainment may provide a mechanism for breathing to alter brain waves, such as the increase in delta activity during slowed respiration. If respiration truly acts as a fundamental organizer of oscillatory brain activity, then surely its modulation could be utilized to modulate brain activity to promote sleep.
In this perspective article, in agreement with a prevailing evolutionary mismatch hypothesis that hyper-arousal accompanied by sympathetic hyperactivation and parasympathetic hypoactivation is a major pathogenic mechanism of insomnia, we have suggested that modulation of the ANS via slow breathing techniques in adjunct to relaxation techniques and sleep hygiene may be a more powerful tool in combating insomnia than the prevailing method of using hypnotics and other pharmaceutical interventions. In respect to the close relationship between the ANS, sleep physiology, mental state, and respiration discussed, it is clear that people have or develop the ability to alter arousal levels voluntarily. We have proposed that slow breathing and other relaxation methods may attenuate the “mismatch disease” of autonomic hyper-arousal and help people deal with the arousing pressure to sleep. Although there is significant support for the efficacy of relaxation and sleep-hygiene techniques in treating insomnia, very limited research investigating treatment with slow, deep breathing. Through our perspective, we hope to inspire debate, discussion, and future research into insomnia as a “mismatch disease” and the effectiveness of slow breathing in attenuating autonomic hyper-arousal.