Sleep Problems After Cardiac Arrest: Causes and Solutions

Sleep problems after cardiac arrest are extremely common and are frequently underreported to clinical teams. Survivors often assume that poor sleep is simply part of recovery — something to be endured rather than addressed. It is not. Sleep is one of the most important drivers of physical and psychological recovery, and persistent sleep difficulties can compound fatigue, mood disorders, cognitive problems, and cardiac risk. If you are not sleeping well after a cardiac arrest, it is worth taking seriously and worth raising with your GP.

Why Cardiac Arrest Disrupts Sleep

Sleep disruption after cardiac arrest is rarely a single problem with a single cause. It typically arises from a combination of factors that interact with each other, making it important to understand what is driving the difficulty before deciding how to address it.

Trauma and hyperarousal

Cardiac arrest is a traumatic event. One of the hallmarks of trauma is hyperarousal — a state of persistent nervous system activation that keeps the body on high alert. This is the opposite of what sleep requires. The brain, having registered a genuine threat to life, may resist the vulnerability of sleep, particularly in the early weeks and months after the event. Nightmares and intrusive memories during the night are common manifestations of this. For more on the relationship between cardiac arrest and trauma, see our page on Trauma After Cardiac Arrest.

Anxiety and rumination

The quiet of bedtime removes the distractions of the day and can leave survivors alone with their fears — about recurrence, about health, about the future. Anxiety is strongly associated with difficulty falling asleep and with waking in the night unable to return to sleep. Rumination — repetitive, looping anxious thoughts — is a particularly disruptive pattern. See our page on Anxiety After Cardiac Arrest for a fuller account of how anxiety manifests and what helps.

Medication effects

Many medications commonly prescribed after cardiac arrest can affect sleep. Beta-blockers, in particular, are associated with vivid dreams, nightmares, and disrupted sleep architecture in some patients. Diuretics can cause nocturnal waking due to increased urination. Antiarrhythmics and some anticoagulants may also affect sleep quality. It is always worth checking whether a medication change coincided with a change in sleep, and raising this with your cardiologist or GP. Never adjust cardiac medication without medical advice, but do raise sleep side effects — alternatives may be available. Our Medications page covers post-cardiac arrest prescribing in more detail.

Brain injury and circadian disruption

Hypoxic brain injury — caused by the interruption of blood flow and oxygen to the brain during cardiac arrest — can affect the areas of the brain that regulate sleep-wake cycles. This can result in disrupted circadian rhythms, excessive daytime sleepiness, difficulty maintaining sleep at night, and changes in the structure of sleep stages. These effects can persist for months and are worth discussing with a neurologist or sleep specialist if they are significantly affecting quality of life.

Depression

Depression and sleep problems have a bidirectional relationship — each makes the other worse. Depression is common after cardiac arrest and frequently presents with early morning waking, difficulty getting to sleep, or hypersomnia. If low mood, loss of interest, fatigue, and sleep difficulties are occurring together, it is important to address the depression directly rather than only the sleep symptoms. See our page on Depression After Cardiac Arrest.

Common Sleep Problems After Cardiac Arrest

Insomnia

Insomnia — difficulty falling asleep, staying asleep, or waking significantly earlier than intended — is the most commonly reported sleep problem after cardiac arrest. It can develop quickly in the aftermath of the event and, if not addressed, can become a persistent pattern that is harder to shift the longer it continues. Cognitive Behavioural Therapy for Insomnia (CBT-I) has the strongest evidence base of any treatment for chronic insomnia and is now recommended by NICE as a first-line treatment ahead of medication. It is available through some NHS Talking Therapies services and via digital programmes.

Nightmares and intrusive dreams

Nightmares are one of the hallmark symptoms of PTSD and are very common in cardiac arrest survivors, particularly in the weeks and months following the event. They may directly replay the arrest, or may take indirect forms — themes of danger, helplessness, or loss. Nightmares are distressing in themselves and disrupt sleep quality by causing waking and heightened arousal. They tend to improve as the underlying trauma response is addressed. Image Rehearsal Therapy (IRT) is a specific technique for chronic nightmare disorder that has good evidence and can be used alongside trauma-focused therapies. Our page on PTSD After Cardiac Arrest covers the treatment options in more depth.

Sleep apnoea

Obstructive sleep apnoea (OSA) — where the airway repeatedly collapses during sleep, causing brief interruptions to breathing — is significantly more prevalent in people with cardiovascular disease than in the general population. It is associated with increased cardiac risk and can seriously compromise sleep quality, leading to unrefreshing sleep, excessive daytime tiredness, morning headaches, and difficulty concentrating. Many survivors are undiagnosed. If you or your partner have noticed loud snoring, gasping or choking during sleep, or if you wake unrefreshed regardless of how long you sleep, ask your GP about a sleep study referral. The NHS sleep apnoea page has further information on symptoms and diagnosis.

Restless legs syndrome

Restless legs syndrome (RLS) causes an uncontrollable urge to move the legs — typically in the evening or at night — accompanied by uncomfortable sensations that are temporarily relieved by movement. It can make falling asleep very difficult and significantly fragments sleep when it occurs during the night. RLS has associations with iron deficiency, kidney disease, and certain medications, all of which can be relevant in the post-cardiac arrest context. It is worth raising with your GP as it is often treatable once properly identified.

Not all sleep problems after cardiac arrest involve too little sleep. Some survivors sleep excessively — particularly in the early recovery period — and still feel unrefreshed. This can reflect the brain’s need to repair and consolidate, but persistent hypersomnia may also be a sign of depression, medication side effects, or undiagnosed sleep apnoea. If excessive sleep is limiting your ability to rehabilitate or return to normal activities, it is worth investigating rather than accepting as inevitable. For more on managing recovery-related exhaustion, see our page on Managing Fatigue After Cardiac Arrest.

Improving Sleep After Cardiac Arrest

Sleep hygiene

Sleep hygiene refers to the habits and environment that support good sleep. While sleep hygiene alone is unlikely to resolve significant sleep problems after cardiac arrest, it provides a foundation on which other approaches can build. Key principles include going to bed and waking at consistent times (even at weekends), keeping the bedroom cool, dark, and quiet, avoiding screens in the hour before bed, and not lying awake in bed for prolonged periods — if sleep does not come within 20 minutes, getting up briefly and doing something calm before returning.

Addressing the underlying cause

Because sleep problems after cardiac arrest usually have identifiable causes — trauma, anxiety, depression, medication, neurological changes — addressing those causes directly tends to be more effective than focusing on sleep alone. If nightmares and hyperarousal are the primary problem, trauma-focused therapy is likely to help more than sleep hygiene advice. If rumination and anxiety are preventing sleep onset, psychological therapy addressing the anxiety is the appropriate intervention.

Relaxation and wind-down techniques

Progressive muscle relaxation, slow diaphragmatic breathing, and body scan meditation can all help to reduce physiological arousal in the hour before bed. These approaches work by activating the parasympathetic nervous system — effectively signalling to the body that it is safe to rest. The NHS mindfulness resources include free guided practices that are appropriate for use as part of a wind-down routine.

Diet and stimulants

Caffeine has a half-life of approximately five to six hours, meaning that a cup of coffee at 3pm can still be affecting sleep at 11pm. Alcohol, despite its sedating effect, significantly disrupts sleep architecture — particularly REM sleep — and tends to cause waking in the second half of the night as it is metabolised. Both are worth reviewing if sleep quality is poor. Our page on Alcohol After Cardiac Arrest has more detail on how alcohol specifically affects recovering survivors.

Talking to your GP

Persistent sleep problems after cardiac arrest are a clinical issue, not simply a lifestyle one. Your GP can review your medication for sleep-disrupting effects, refer you to NHS Talking Therapies for CBT-I or anxiety treatment, request a sleep study if sleep apnoea is suspected, and consider short-term medication where appropriate. Do not assume that poor sleep is simply part of recovery that must be accepted.

Sleep Problems in Co-Survivors

Partners and family members of cardiac arrest survivors frequently report their own significant sleep difficulties. Hypervigilance — listening for changes in the survivor’s breathing, waking at every movement — is extremely common. Nightmares about the arrest are also reported by many co-survivors, particularly those who performed CPR. These experiences are valid and deserve acknowledgement and support in their own right. Our Co-Survivors page addresses the broader impact of cardiac arrest on those closest to the survivor.