Sleep

Sleep Help And Advice

It is very common to struggle with your sleep after you have had a heart attack. There will be a lot going through your head at this time, which often can impact your sleep. It is important to get rest when you are recovering and many people will need to also recover from the effects of a hospital admission. When in hospital your sleep is often poor owing to many factors such as the machines or people monitoring your vital signs; the snoring from your neighbours; the alarms going off down the corridor; the unfamiliar surroundings and stress of your acute illness. It will take a little time just to catch up on this interrupted sleep pattern.

Furthermore, you might be experiencing effects from new medications or devices, such as diuretics or a CPAP machine, that might be waking you in the night to go to the toilet or due to discomfort. Poor sleep can hinder your rehabilitation time and/ or make the problem worse. This not only causes physical problems; but also worsen mental health, leading to anxiety and depression.

Sleep deprivation affects much of our physiology and the depth of its importance is still not completely known to us. Sleep plays a crucial role in both mental and physical recovery, as it allows the brain to naturally eliminate waste products and toxins that build up during the day. This process occurs mainly through the glymphatic system, which enables fluid to circulate through the brain and clear out these waste materials. In essence, the brain “cleans itself” while you sleep.

When sleep deprivation occurs and the glymphatic system isn’t able to function properly, the brain struggles to remove waste products and toxins that build up throughout the day. This can lead to a buildup of harmful substances, such as beta-amyloid, a protein associated with Alzheimer’s disease. Without the cleansing action of the glymphatic system, these waste products accumulate in the brain, potentially increasing the risk of neurodegenerative diseases and impairing cognitive functions like memory, attention, and decision-making. Chronic sleep deprivation can also impair overall brain health, contribute to inflammation, and negatively affect mood, further disrupting mental and physical recovery processes. The complexity increases further because there is a lot of overlap in long term illnesses and sleep disorder. High blood pressure, obesity, systemic inflammation, diabetes, sleep apnoea and depression all overlap each other significantly and can potentiate worse sleep patterns.

II hope this highlights why we place great importance on dedicating time to improving your sleep. The body of research available also backs the physiology by consistently showing that targeted treatment for sleep disorders has been shown to improve multiple factors and co-existing illnesses associated with prognosis after a heart attack. Most significantly it has been shown to improve quality of life and significantly reduced short-term and long-term death rates. Importantly, depression post-MI can be significantly reduced by focusing on the treatment of any underlying sleep disorders._¹

The study of sleep is still in its early stages, prompting researchers to explore a broad range of factors influencing various outcomes in an effort to replicate findings and deepen understanding. They have also looked at a variety of key components of sleep, such as duration, timing, quality, interruptions, napping and breathing disturbances. Hopefully over the coming years more clarity about the intricacies of health and sleep will become available. The strongest conclusions we’ve drawn regarding heart health suggest aiming for 7,8 hours of sleep while maintaining a consistent routine. Even in good health, this can be challenging, but we’re here to help you find strategies to achieve it. Some studies indicate better outcomes for those who sleep before midnight and those that experience fewer interruptions during their sleep (possibly a big contributing factor with sleep apnoea). Additionally, lower light exposure has been linked to reduced risk, as has daytime napping in individuals under 65. Focusing solely on heart health already reveals that sleep plays a far more significant role than we once thought!

Sleep Apnoea

Sleep apnoea is a sleep disorder in which breathing repeatedly stops and starts during sleep. The main cause is due to Obstructive sleep apnea (OSA), which happens when the muscles in the throat relax too much during sleep, causing the anatomy to collapse on the airway thereby creating a temporary blockage of the airway. This prevents normal breathing, leading to repeated pauses in breathing (called apnoeas) throughout the night. This interruption in breathing means we get less oxygen into our lungs and breath out less carbon dioxide. This results in a reduction in oxygen levels in the blood and causes a rise in carbon dioxide (forming carbonic acid and thereby making the blood more acidic). It is this rise in acidity that causes the brainstem to engage and wakes you to take a deep breath. Sleep apnoea causes many other unwanted effects including persistently high fight-or-flight hormones in our system (cortisol) and excessive daytime sleepiness. It also has significant impact on our metabolism putting us at risk of hypertension, obesity, diabetes and high lipids. All of this leads to faster progression to plaque formation in our blood vessels.

Interestingly, due to the long term exposure to low oxygen, there is a slight protective effect when someone has a heart attack because the lack of oxygen is not felt as severely by the tissues that are already conditioned to periods of lower oxygen.
In both chronic insomnia and in sleep apnoea higher levels of fibrinogen (a key blood clotting factor) are found in the blood putting us at higher risk of clots in our bodies, which is even more important if addition to atrial fibrillation, where static blood is more likely to clot in the top chambers of the heart.

It is easy for sleep apnoea to go unnoticed unless our partners mention it. There are certain risk factors to look out for including: obesity, smoking, alcohol consumption, family history, nasal congestion and progressive age. If you think you might have sleep apnoea please consult The Sleep Apnoea Trust website and take a look at the Epworth Sleep Scale (https://sleep-apnoea-trust.org/wp-content/uploads/2020/08/Epworth-Sleepiness-Scale-for-SATA.pdf)

Cardiovascular System

Sleep deprivation has been shown to result in the disruption of our circadian (day-night) cycle of our heart cells. This leads to malignments of their molecular clock, which consequently causes a disturbance in metabolic balance (homeostasis) making cells more vulnerable to physiological stress (e.g. if receiving less oxygen). It has also been shown to reduce function of the top chambers (atria) and reduce cardiac output in heart failure, which is certainly not ideal.

Sleep deprivation has also been shown to reduce our heart rate variability after exercise, which may be important to many who are used to keeping very fit. Recurrent sleep restriction has also been shown to increase cardiac stress response related to acute high intensity exercise, which may shoot your heart rate up higher than is healthy.
The quality of sleep seems to be particularly important to women. Studies have shown that mortality both one month after a heart attack and also at ten-year follow up is higher in groups that report poor quality sleep.

Blood Pressure

Studies have shown that sleep deprivation increases the activity of the sympathetic nervous system (the body’s fight or flight system), thereby increasing blood pressure and heart rate during the night and the following morning. Furthermore, sleep deprivation has also been shown to increase our cortisol, which increases our blood pressure further._⁴

There is ample evidence showing the link between cardiovascular risk and high blood pressure. It is normal to have a short period of raised blood pressure after surgery, however, if this is prolonged, it can lead to longer healing times due to poor blood supply. This causes reduced oxygen and nutrients to the wound for healing and also reduces the removal of waste materials and toxins.

Inflammation

Inflammation is a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection. Our understanding of many disease processes in the human body now have inflammation as the core underlying problem. This can lead to heart disease, Alzheimer’s, Parkinson’s, inflammatory bowel disease and arthritis. It is therefore vital that we prioritise getting into a good sleep pattern to minimise our systemic inflammation and reduce our risk of progression to these illnesses.
Numerous studies have suggested a link between sleep deprivation and inflammation within the body. Although there are several theories of why inflammatory markers are raised with poor sleep, the exact reason is not fully understood. One theory is that during deep sleep, our body’s glymphatic system (which removes waste and regulates fluid movement) is active. If we do not get to this deep sleep state, the activity of this system is decreased.

Anxiety And Depression

Sleep deprivation is a key component in increasing levels of anxiety and even depression. Insomnia has been proven to increase the rates of panic attacks, leading to many feeling isolated and unable to carry out their usual activities, at work or socially.

Anxiety and depression can affect all aspects of life. An often over-looked contributing factor to anxiety as a consequence of heart disease (and its medical treatment) is erectile disfunction (ED) and lowered sex drive (libido). Sleep deprivation can lead to increasing anxiety on top of an already stressful situation which can worsen the effects on sexual function. It is vital that these topics are discussed openly in a safe space in order to reduce the stigma associated and attempt to resolve the issues. Some brave patients have shared their stories on the British Heart Foundation website, which you might find helpful. At Heart and mind clinics, we invite you to talk about these issues as a natural part of your healing process and if necessary, further referrals can be made to psychosexual counsellors.
So how does sleep deprivation have such an impact on our mental wellbeing? Major depression is linked to impaired function of the autonomic nervous system. The autonomic nervous system (ANS) is the part of your nervous system that works automatically to control things your body does without you thinking about them. It manages essential functions like breathing, heart rate, digestion, and blood pressure. Impaired regulation of this can in turn lead to abnormal heart rate variability, which can interfere with the heart’s ability to deliver oxygen and recover after injury. It also leads to dysfunction of the lining of our arteries (the endothelium) and our platelets (involved in blood clotting). heart attacks and strokes. This, combined with the increased systemic inflammation we discussed earlier and a reduced ability of our arteries to adjust their diameter, results in more plaque buildup in the arteries, raising the risk of blockages that can lead to heart attacks and strokes.

Disruption of the equilibrium of our nervous system also impacts our serotonin and dopamine hormones. Serotonin and dopamine are both neurotransmitters, which are chemicals that help transmit signals in the brain and play important roles in regulating mood, emotions, and mental wellbeing. Serotonin, often called the “feel-good” neurotransmitter, helps regulate mood, anxiety, and happiness. It contributes to feelings of calm and emotional stability. Low levels of serotonin are linked to depression, anxiety, and other mood disorders, which lead to the development of medications called SSRI to boost concentrations of this hormone.

Dopamine is known as the “reward” neurotransmitter: it plays a key role in motivation, pleasure, and the brain’s reward system. It is associated with feelings of enjoyment and reinforcement, encouraging behaviour that feels rewarding. Imbalances in dopamine can lead to conditions like depression, addiction, and attention-related issues (e.g., ADHD). Chronic lack of sleep can both lower dopamine production but also lower the brain’s sensitivity to dopamine receptor activation, meaning your brain becomes less responsive to dopamine. This leads to feelings of reduced motivation, pleasure, and reward, even when engaging in enjoyable activities.

Executive Function And Concentration

Poor concentration as a result of sleep deprivation is no surprise to anyone. Evidence suggests that acute sleep deprivation has greater immediate effects. However, chronic sleep deprivation has significant effects on our long and short term memory consolidation. People who are exposed to sleep loss usually experience a decline in cognitive performance and changes in mood.
As we have seen already, the impact of sleep on our brains is complex and not fully understood. There has been a lot of research into total sleep deprivation but less so into partial sleep deprivation. It has shown that the frontal brain areas are vulnerable to sleep deprivation, including the prefrontal cortex, which is important in so many higher cognitive functions, such as language, executive functions, divergent thinking, and creativity.
Aging also influences our ability to cope with sleep deprivation; in which older patients actually seem to cope better with less sleep (where younger people of especially affected in terms of performance speed). Women may also endure prolonged wakefulness better than men, whereas physiologically they recover slower. The mechanisms to explain both these differences remains unclear and may rely on numerous physiological mechanisms as well as social or environmental factors.

Blood Sugars

Poor sleep and later sleeping times are associated with poor blood sugar control in the morning. Insufficient sleep can lead to high fasting blood sugar levels, elevated glucose after meals, and high insulin levels. Total sleep deprivation can also lead to insulin resistance, β-cell dysfunction (the pancreatic cells that make insulin), and thereby also defects in insulin secretion. This increases the risk of diabetes and therefore increased cardiovascular risk.

From this it is not surprising that inadequate sleep can also worsen glucose control in patients with type 2 diabetes. Sleep is important for regulating our metabolism, so when you don’t get enough sleep, your pancreas may not be able to produce enough insulin to process the additional sugar in your body. This can lead to unhealthy amounts of sugar in your bloodstream and high blood sugar levels.

All of this sounds scary and it may even feel like an unsurmountable challenge but, here at Heart and mind clinics, we want give you the best chance to recover to your old self as quickly as possible. We want to lay out the evidence as it currently stands to give you knowledge to empower you to improve your health and focus of reducing the risk of further physical and psychological problems. By improving many aspects of your life we can noticeably reduce your risk piece by piece and get you fitter and more resilient than before.

Top Tips For Better Sleep

Listen to your body. Our body has a way of telling us what we need but we aren’t always great at listening to it! This means only go to bed when you are tired , it sounds obvious but this also means if its earlier than expected!
Have a quiet hour before bed and turn off your screens. It is possible that blue light may impact our sleep but it may be more important what you are doing on your devices in terms of stimulus. Ideally turn to a book and /or practice meditation!
Practice relaxation , this means identifying the things that help you to switch off. This may mean a hot bath which can promote muscle and mind relaxation. Drinking herbal teas with fennel or lavender before bed can help too.
Listen to music until you drift off: many apps have both ready-made playlists and sleep timers to limit how long the music plays.
Be active during the day: exercise promotes quality sleep and will help you fall asleep quicker and sleep longer. Furthermore, exercise is an important component of cardiac rehabilitation and should be part of everyday activity.
Avoid stimulants after midday: stay clear of caffeine at least from midday onwards as this will stimulate the brain more and make it harder to fall asleep. They also cause an increase in heart rate, blood pressure and blood sugar, constricting blood vessels. Also avoid processed sugar as much as possible because this has an impact on your weight (can impact sleep apnoea).
If you are still awake after this time, get up until you feel drowsy. Repeat until you fall asleep. It may take a few days of getting up, but eventually you should find that you can fall asleep much more easily.

Sleep Medication

Try to avoid using sleep medication. Most sleep medications are sedative and often leave you feeling tired in the morning or with a bad metallic taste (zopiclone). They also don’t improve your sleep quality in the long term. It is much better to address your sleep hygiene to promote good long term sleep habits. Sleep medications can be helpful at times to help reset your sleep pattern in the case of a temporary sleep disturbance (e.g. acute stress, travelling).
New medications on the market are finally providing some exciting data in treating insomnia. They block the action of orexin, a neuropeptide that promotes wakefulness. The two common trade names are daridorexant and lemborexant. They are non-sedative with low rates of somnolence and fatigue as side effects but may not be suitable if you suffer from headaches. There is also some evidence suggesting they may help reduce anxiety and hyperarousal, which likely helps in their effect. They are currently not available on the NHS in primary care but may provide a welcome hand in combatting sleep disorder after recent physical illness and we can issue these privately for you.