Delayed sleep phase syndrome (DSPS) is a most prevalent circadian rhythm sleep disorder and is marked by a delay in the timing of sleep episode compared to desired or necessary sleeping and wakeup times. This results in difficulty falling asleep and, as a consequence, challenges in waking up at the desired or required times. The circadian rhythm is a 24 hours cycle regulated by your biological clock that governs vital body functions such as temperature, hunger, digestion, hormone release, and the timing of sleep and wakefulness. Light and darkness play a key role in regulating this rhythm, which can be disrupted by factors like late-night exposure to electronic screens or jet lag from crossing time zones.
Circadian aligned melatonin is released less than three hours before sleep onset. Melatonin release occurs only after sleep onset. This misalignment with societal norms can result in impaired functioning, including daytime sleepiness, decreased academic or work performance, and general mental and physical fatigue. The primary feature of DSPS is a significant delay in sleep onset, often by 2 hours or more compared to typical sleep schedules. For example, a person with DSPS might naturally fall asleep at 2 AM or later but needs to wake up early for work or school. Due to the delayed sleep onset, individuals with DSPS often find it hard to wake up in the morning, even when required to do so. They may experience excessive daytime sleepiness, fatigue, and difficulty concentrating. This is often misdiagnosed as insomnia due to the similarities in sleep difficulties. However, DSPS and insomnia are different conditions with underlying causes and treatment approaches. Accurate diagnosis is key to ensuring the appropriate treatment is provided, allowing individuals with DSPS to better align their sleep-wake cycles and improve overall sleep quality.
Auricular vagal nerve stimulation
Auricular Vagal Nerve Stimulation (aVNS) is a neuromodulation method that targets the auricular branch of the vagus nerve. This technique has demonstrated therapeutic benefits for many conditions, including sleep disorders too. Vagus nerve is the key component of the parasympathetic nervous system, which has a function of regulating the body's "rest and digest" functions, including heart rate, digestion, and sleep. The vagus nerve’s auricular branch has a connection to the brainstem and structures involved in regulating circadian rhythms and sleep, such as the hypothalamus and pineal gland. Stimulating this nerve is believed to influence the release of neurotransmitters and hormones such as melatonin, a key regulator of sleep-wake cycles, thereby improving sleep quality. It was found that vagal nerve stimulation, might enhance the release of melatonin, a key hormone involved in regulating the sleep-wake cycle, and this could contribute to improved sleep timing and quality, particularly in individuals with circadian rhythm disturbances. For individuals with delayed sleep phase syndrome, stimulation of the auricular vagus nerve naturally could help shift the circadian rhythm, making it easier for individuals to fall asleep earlier and wake up at desired times. Auricular acupressure involves applying pressure to specific points on the ear, which are associated with various physiological functions, including relaxation, sleep regulation, and mood balance. Auricular acupressure is a promising natural approach to managing DSPS. By stimulating key acupoints on the ear, this technique can assist in regulating the circadian rhythm, enhancing sleep quality, and alleviating anxiety. The common points include the acupoint located on the upper third of the ear, in the triangular fossa, sleep point located on the ear's inner side, just above the ear canal, and is often used in auricular therapy & point zero is located at the centre of the ear, in the concha area. For a simple approach, use your thumb and index finger to apply gentle pressure to the ear acupressure points. Massage the points in small, circular motions for about 1-3 minutes. For best results, auricular acupressure can be done 1-2 times per day, especially in the evening, before bedtime. Consistency is key to helping shift the body’s sleep cycle. Auricular acupressure is a natural and non-invasive treatment. It does not come with the risk of side effects or dependency, making it a safe option for long-term use. People with delayed sleep phase syndrome and other sleep disorders often experience anxiety or stress about their irregular sleep patterns. This natural stimulation can reduce these feelings, helping to calm the nervous system and prepare the body for rest. As a non-invasive treatment, it can be a valuable addition to melatonin supplementation.
Role of melatonin
Melatonin is a hormone essential for regulating sleep and the circadian rhythm. It is mainly produced by the pineal gland in the brain, with smaller amounts also generated by other tissues. The production of melatonin is influenced by light exposure, often referred as the "sleep hormone." Melatonin helps regulate the body's internal clock, or circadian rhythm, by indicating sleep time. Its production rises as darkness sets in, reaching its peak during the night to induce drowsiness. With the arrival of morning light, melatonin levels drop, signalling the body to wake up. Melatonin aids in falling asleep faster by promoting relaxation and reducing alertness. While it doesn’t directly induce sleep, it plays a vital role in preparing the body for rest by aligning it with the natural light-dark cycle. In addition to promoting sleep, melatonin also helps regulate sleep stages, including deep sleep (slow-wave sleep). Proper melatonin levels are important for achieving restful, restorative sleep, which is crucial for both physical and mental health. Melatonin production is tightly connected to the light-dark cycle. It remains low during the day and increases at night, signalling the body that it's time to sleep. This light-dependent pattern makes melatonin supplementation particularly helpful for individuals with circadian rhythm disorders. This is especially beneficial for those whose internal clock is misaligned with societal time, making it hard to fall asleep. In individuals with DSPS, melatonin is released later than usual, making it hard for to sleep at normal bedtimes and often causing trouble waking up in the morning. Melatonin supplementation can help individuals with DSPS fall asleep more quickly by promoting drowsiness and can be an effective way to manage by resetting the timing of melatonin release and helping realign the circadian rhythm. Melatonin supplements are often used to treat sleep disorders and encourage sleep, but they should be taken with caution. The timing of melatonin supplementation is crucial. Taking it too early or too late in the evening can interfere with the circadian rhythm. Generally, a dose of 0.5-3 mg taken 30-60 minutes prior to bedtime works for most people, though the ideal dosage may differ from person to person. The length of time melatonin is used can vary. Some individuals may only require it for a few weeks to reset their circadian rhythm, while others may need it for a longer duration. As with any supplement, melatonin should be used under the guidance of a healthcare provider.
The combination of aVNS and melatonin supplementation offers a promising approach to managing DSPS and improving sleep quality. When used together, aVNS and melatonin supplementation may have complementary effects on regulating the circadian rhythm. aVNS helps soothe the nervous system and reduce stress, making it easier for individuals to fall asleep, while melatonin supplementation sends a direct hormonal signal to regulate sleep timing. Together, these treatments could improve sleep quality and assist in resetting the body’s internal clock, gradually aligning the sleep-wake cycle with a more typical rhythm. This approach may provide a non-invasive, holistic treatment for those with DSPS, offering both physiological and hormonal support for circadian rhythm regulation. When applied regularly, aVNS can support the synchronization of the body's internal clock with the external environment, benefiting those with DSPS, and DSPS is a disruptive condition that impacts many individuals, often making it difficult to maintain regular sleep patterns. However, emerging treatments such as auricular vagus nerve stimulation and melatonin supplementation offer hope for realigning the circadian rhythm and improving sleep quality. By addressing different components of the sleep-wake cycle, these therapies may work synergistically, providing a well-rounded approach to managing DSPS.
As research into the combined use of vagal nerve stimulation and melatonin continues to grow, these treatments could become essential tools for those struggling with DSPS. By offering both physiological and hormonal support, they hold the potential to not only improve sleep but also enhance overall well-being. With further study and refinement, these therapies may play a crucial role in helping individuals restore normal sleep patterns and significantly improve their quality of life.
(The authors are faculty Saveetha College of Physiotherapy, Saveetha Institute of Medical and Technical Sciences, Chennai) |