Insomnia
Understanding the mechanisms and role of sleep
A decent night’s sleep sustains good physical and mental health. Evidence shows that, for most of us, our bodies and brains – our own complex and sophisticated computers – need between 7 and 8 hours sleep each night, but this is not always easy to achieve in the hurly-burly of modern society
Insufficient sleep, resulting from too few hours or poor quality, undermines our health and our ability to function. Loss of sleep can influence all the major physiological systems increasing the chances of cardiovascular disease and diabetes as well as a weakened immune system, increased risk of cancer, dementia, and poor mental health including depression and anxiety.
Understanding the mechanisms and function of sleep is important for understanding and treating sleep disorders the most common of which is insomnia. Insomnia is defined as difficulty in falling asleep, staying asleep or nonrestorative sleep which occurs more than three times a week for at least three months. Rates of insomnia appear to increase with age. Symptoms of insomnia were reported in 12% of 25-45-year-olds but in a sample of over 65s, 55% reported insomnia over the last month.
What is sleep?
The best sleep includes both the duration and the quality of sleep. Good quality sleep has distinct phases identified by different brain wave frequencies. There are two main phases, non-rapid-eye-movement (NREM) and rapid eye movement (REM). NREM is deep slow wave sleep and predominates early in the night whereas in REM brain waves are fast and desynchronised. REM is more frequent in the second half of the night, and this is when dreaming occurs. These two phases change from one to another across the night each cycle lasting approximately 90 minutes.
The overall function of sleep is to provide recovery from the preceding days activities and to ensure optimal function for the following day. NREM and REM sleep make complementary contributions particularly in the formation and consolidation of memories. During the slow brain waves of NREM information from short-term memory in the hippocampus of the brain is moved into long-term memory which frees up space in the short-term memory for the events of the next day. Also, during NREM work is done to weed out and remove unnecessary neural connections. During REM new knowledge is compared to past experiences so connections can be made between past and new information. The function of REM/ dreaming is to support waking memory consolidation, mood regulation and creativity.
Sleeping is controlled by the interaction of two processes. Process S is a homeostatic mechanism involving the chemical adenosine in the brain. Adenosine builds up during wakefulness in the day and dissipates when asleep at night. The accumulation of adenosine results from the use of adenosine triphosphate (ATP) as an energy source by active nerve cells and is associated with a feeling of sleepiness. Interestingly caffeine is as an adenosine receptor antagonist which explains why it is difficult to sleep after drinking coffee. The other process is Process C the internal circadian rhythm which is approximately 24 hours. This internal clock is controlled by a part of the hypothalamus called the suprachiasmatic nucleus (SCN) and is synchronised by the light-dark cycle. A regular pattern of sleep and wake timing coincides with the build-up of adenosine over the day so sleep pressure is high in the evening at the time of going to bed.
Melatonin, a hormone secreted by the pineal gland plays an important part in regulating the sleep wake cycle and the circadian clock. Melatonin is secreted in the dark at night and release is inhibited by light during the day. The daily rhythm of melatonin production is driven by the SCN and synchronised to the light/dark cycle via light input through the eyes. During the day the SCN prevents melatonin production by sending inhibitory messages to the pineal gland but not at night. This rise of melatonin coincides with the increase in sleep pressure usually about 2 hours before regular bedtime and levels peak around 3.00 to 4.00 in the night. The peak of melatonin coincides with a reduction in in the slow brain waves of NREM sleep and an increase in REM. As morning approaches sleep pressure is reduced and the circadian rhythm begins to promote wakefulness which coincides with the usual time of waking and a circadian peak in cortisol production.
Treating insomnia
Treatment of insomnia depends on the underlying cause but use of sedative drugs such as benzodiazepines and so-called Z drugs are no longer the first choice of treatment. These drugs have serious side effects such as daytime sleepiness and the risk of addiction. The sleep induced by these drugs is not the same as naturel sleep reducing the deepest stage NREM sleep and the restorative benefits of sleep. Nonpharmacological methods of treating insomnia are now the preferred choice. Cognitive behavioural therapy for insomnia (CBT-I) which focuses on behavioural changes to alter sleep patterns and Mindfulness based therapy for Insomnia (MBTI) have both been shown to be effective. While very beneficial these behavioural practices may not be the complete solution.
An integrative approach considering the person as a whole and considering aspects of lifestyle offers the best way for treatment. Such treatment includes consideration of sleep hygiene, diet, and exercise together with complementary therapies such as herbal medicine which can be combined with behavioural and conventional treatment.
Treatment with herbal medicine
Herbal medicines are one of the most popular and frequently used therapies for treating insomnia. They can be readily bought over the counter and allow self-management of short-term periods of insomnia.
Many of the sedative herbs have a similar mechanism of action to sedative drugs acting by influencing the brain chemical messenger gamma amino butyric acid (GABA). This neurotransmitter is inhibitory reducing nerve activity and producing a calming and sedative effect. Herbs that can enhance the action of GABA include:
Herbal medicines are not as strong as sedative drugs, but they have far fewer side effects, and they are not addictive. Herbs contain a range of low dose compounds which combine to produce a sedative action this compares with single compound found in high doses in sedative drugs. A high dose of a compound is less likely to be cleared from the body at the time of waking so more likely to cause drowsiness during the day.
There are several possible causes of insomnia, and these need to be identified if treatment is to be effective long-term. The aim of a Medical Herbalist is to identify the underlying cause and to select a combination of herbs which will provide both sedative actions to treat the symptom of insomnia and other herbal actions to treat the underlying cause. The possible causes of insomnia include:
Stress and anxiety are a common cause of insomnia, and most people have at some time been unable to sleep due to stress and anxiety. If this continues long term it can interfere with the hypothalamic-pituitary- adrenal axis and disrupt the release of cortisol from the adrenal gland. Any change in the circadian pattern of cortisol, peaking in the early morning and decreasing in the evening, will lead to a disruption in sleep. Herbs which are adaptogens can restore adrenal balance and the circadian pattern of cortisol. These include ashwagandha, eleuthero (Eleutherococcus senticosus), holy basil (Ocimum sanctum), liquorice (Glycrrhiza glabra) and rhodiola (Rhodiola rosea). Where anxiety is linked to depression nervine herbs such as St John’s wort (Hypericum perforatum), Skullcap, (Scutellaria lacteriflora), lemon balm (Melissa officinalis) or vervain (Verbena officinalis) will be part of the treatment.
Another common cause of insomnia is the hormonal imbalance which occurs in women during the perimenopause. Treatment includes herbs that balance ovarian hormones such as black cohosh (Cimicifuga racemosa) and vitex (Vitex agnus-castus) together with those that reduce hot flushes such as sage (Salvia officinalis) if these are also disturbing sleep. Vitex is a further aid in the treatment of insomnia as it has been shown to increase night-time melatonin levels.
These examples demonstrate how diagnosis of the cause of insomnia determines the selection of herbs for treatment. This selection can be modified for each individual and combined with advice on sleep hygiene, diet and exercise to improve both the duration and quality of sleep.
Reference sources and further reading
Matthew Walker (2017) Why We Sleep: The New Science of Sleep and Dreams. Penguin Random House, UK
Integrative Sleep Medicine (2021) Edited by Valerie Cacho and Esther Lum. Oxford University Press, UK.
Kerry Bone (2021) Functional Herbal Therapy: A Paradigm for Clinicians. Aeon, UK
Christine Herbert (2021) Sleep the Elixir of Life: How to Restore Sleep with Herbs and Natural Healing. Aeon, UK
Oxford Handbook of Sleep Medicine (2022) Edited by Guy Leschziner. Oxford University Press, UK
Jillian Stansbury, (2010) Herbal Treatment Approaches to Insomnia. Naturopathic Doctor News and Reviews. https://ndnr.com/botanical-medicine/herbal-treatment-approaches-to-insomnia/
Understanding the mechanisms and role of sleep
A decent night’s sleep sustains good physical and mental health. Evidence shows that, for most of us, our bodies and brains – our own complex and sophisticated computers – need between 7 and 8 hours sleep each night, but this is not always easy to achieve in the hurly-burly of modern society
Insufficient sleep, resulting from too few hours or poor quality, undermines our health and our ability to function. Loss of sleep can influence all the major physiological systems increasing the chances of cardiovascular disease and diabetes as well as a weakened immune system, increased risk of cancer, dementia, and poor mental health including depression and anxiety.
Understanding the mechanisms and function of sleep is important for understanding and treating sleep disorders the most common of which is insomnia. Insomnia is defined as difficulty in falling asleep, staying asleep or nonrestorative sleep which occurs more than three times a week for at least three months. Rates of insomnia appear to increase with age. Symptoms of insomnia were reported in 12% of 25-45-year-olds but in a sample of over 65s, 55% reported insomnia over the last month.
What is sleep?
The best sleep includes both the duration and the quality of sleep. Good quality sleep has distinct phases identified by different brain wave frequencies. There are two main phases, non-rapid-eye-movement (NREM) and rapid eye movement (REM). NREM is deep slow wave sleep and predominates early in the night whereas in REM brain waves are fast and desynchronised. REM is more frequent in the second half of the night, and this is when dreaming occurs. These two phases change from one to another across the night each cycle lasting approximately 90 minutes.
The overall function of sleep is to provide recovery from the preceding days activities and to ensure optimal function for the following day. NREM and REM sleep make complementary contributions particularly in the formation and consolidation of memories. During the slow brain waves of NREM information from short-term memory in the hippocampus of the brain is moved into long-term memory which frees up space in the short-term memory for the events of the next day. Also, during NREM work is done to weed out and remove unnecessary neural connections. During REM new knowledge is compared to past experiences so connections can be made between past and new information. The function of REM/ dreaming is to support waking memory consolidation, mood regulation and creativity.
Sleeping is controlled by the interaction of two processes. Process S is a homeostatic mechanism involving the chemical adenosine in the brain. Adenosine builds up during wakefulness in the day and dissipates when asleep at night. The accumulation of adenosine results from the use of adenosine triphosphate (ATP) as an energy source by active nerve cells and is associated with a feeling of sleepiness. Interestingly caffeine is as an adenosine receptor antagonist which explains why it is difficult to sleep after drinking coffee. The other process is Process C the internal circadian rhythm which is approximately 24 hours. This internal clock is controlled by a part of the hypothalamus called the suprachiasmatic nucleus (SCN) and is synchronised by the light-dark cycle. A regular pattern of sleep and wake timing coincides with the build-up of adenosine over the day so sleep pressure is high in the evening at the time of going to bed.
Melatonin, a hormone secreted by the pineal gland plays an important part in regulating the sleep wake cycle and the circadian clock. Melatonin is secreted in the dark at night and release is inhibited by light during the day. The daily rhythm of melatonin production is driven by the SCN and synchronised to the light/dark cycle via light input through the eyes. During the day the SCN prevents melatonin production by sending inhibitory messages to the pineal gland but not at night. This rise of melatonin coincides with the increase in sleep pressure usually about 2 hours before regular bedtime and levels peak around 3.00 to 4.00 in the night. The peak of melatonin coincides with a reduction in in the slow brain waves of NREM sleep and an increase in REM. As morning approaches sleep pressure is reduced and the circadian rhythm begins to promote wakefulness which coincides with the usual time of waking and a circadian peak in cortisol production.
Treating insomnia
Treatment of insomnia depends on the underlying cause but use of sedative drugs such as benzodiazepines and so-called Z drugs are no longer the first choice of treatment. These drugs have serious side effects such as daytime sleepiness and the risk of addiction. The sleep induced by these drugs is not the same as naturel sleep reducing the deepest stage NREM sleep and the restorative benefits of sleep. Nonpharmacological methods of treating insomnia are now the preferred choice. Cognitive behavioural therapy for insomnia (CBT-I) which focuses on behavioural changes to alter sleep patterns and Mindfulness based therapy for Insomnia (MBTI) have both been shown to be effective. While very beneficial these behavioural practices may not be the complete solution.
An integrative approach considering the person as a whole and considering aspects of lifestyle offers the best way for treatment. Such treatment includes consideration of sleep hygiene, diet, and exercise together with complementary therapies such as herbal medicine which can be combined with behavioural and conventional treatment.
Treatment with herbal medicine
Herbal medicines are one of the most popular and frequently used therapies for treating insomnia. They can be readily bought over the counter and allow self-management of short-term periods of insomnia.
Many of the sedative herbs have a similar mechanism of action to sedative drugs acting by influencing the brain chemical messenger gamma amino butyric acid (GABA). This neurotransmitter is inhibitory reducing nerve activity and producing a calming and sedative effect. Herbs that can enhance the action of GABA include:
- Valerian (Valeriana officinalis)
- Passionflower (Passiflora incarnata)
- California poppy (Eschscholzia californica)
- Hops (Humulus lupulus)
- Lemon balm (Melissa officinalis)
- Skullcap (Scutellaria lateriflora)
- Nutmeg (Myristica fragans)
- Chamomile (Matricaria recutita)
- Lavender (Lavendula angustifolia)
- Ashwagandha (Withania somnifera)
Herbal medicines are not as strong as sedative drugs, but they have far fewer side effects, and they are not addictive. Herbs contain a range of low dose compounds which combine to produce a sedative action this compares with single compound found in high doses in sedative drugs. A high dose of a compound is less likely to be cleared from the body at the time of waking so more likely to cause drowsiness during the day.
There are several possible causes of insomnia, and these need to be identified if treatment is to be effective long-term. The aim of a Medical Herbalist is to identify the underlying cause and to select a combination of herbs which will provide both sedative actions to treat the symptom of insomnia and other herbal actions to treat the underlying cause. The possible causes of insomnia include:
- Stress, anxiety or depression
- Gastrointestinal disorders
- Menopausal or other hormonal imbalances
- Musculoskeletal restlessness or pain
- Glucose imbalance
Stress and anxiety are a common cause of insomnia, and most people have at some time been unable to sleep due to stress and anxiety. If this continues long term it can interfere with the hypothalamic-pituitary- adrenal axis and disrupt the release of cortisol from the adrenal gland. Any change in the circadian pattern of cortisol, peaking in the early morning and decreasing in the evening, will lead to a disruption in sleep. Herbs which are adaptogens can restore adrenal balance and the circadian pattern of cortisol. These include ashwagandha, eleuthero (Eleutherococcus senticosus), holy basil (Ocimum sanctum), liquorice (Glycrrhiza glabra) and rhodiola (Rhodiola rosea). Where anxiety is linked to depression nervine herbs such as St John’s wort (Hypericum perforatum), Skullcap, (Scutellaria lacteriflora), lemon balm (Melissa officinalis) or vervain (Verbena officinalis) will be part of the treatment.
Another common cause of insomnia is the hormonal imbalance which occurs in women during the perimenopause. Treatment includes herbs that balance ovarian hormones such as black cohosh (Cimicifuga racemosa) and vitex (Vitex agnus-castus) together with those that reduce hot flushes such as sage (Salvia officinalis) if these are also disturbing sleep. Vitex is a further aid in the treatment of insomnia as it has been shown to increase night-time melatonin levels.
These examples demonstrate how diagnosis of the cause of insomnia determines the selection of herbs for treatment. This selection can be modified for each individual and combined with advice on sleep hygiene, diet and exercise to improve both the duration and quality of sleep.
Reference sources and further reading
Matthew Walker (2017) Why We Sleep: The New Science of Sleep and Dreams. Penguin Random House, UK
Integrative Sleep Medicine (2021) Edited by Valerie Cacho and Esther Lum. Oxford University Press, UK.
Kerry Bone (2021) Functional Herbal Therapy: A Paradigm for Clinicians. Aeon, UK
Christine Herbert (2021) Sleep the Elixir of Life: How to Restore Sleep with Herbs and Natural Healing. Aeon, UK
Oxford Handbook of Sleep Medicine (2022) Edited by Guy Leschziner. Oxford University Press, UK
Jillian Stansbury, (2010) Herbal Treatment Approaches to Insomnia. Naturopathic Doctor News and Reviews. https://ndnr.com/botanical-medicine/herbal-treatment-approaches-to-insomnia/
