A concussion, medically known as a mild traumatic brain injury (mTBI), is a temporary functional disturbance to the brain caused by a blow or jolt to the head. While it rarely involves structural damage visible on imaging, it disrupts normal brain function. This disruption frequently manifests as a range of symptoms, with sleep disturbances, particularly the inability to fall or stay asleep, being common during recovery. These sleep problems are a direct consequence of the physical and chemical changes that occur in the brain immediately following the injury.
The Neurological Basis of Sleep Disruption
A concussion initiates a rapid cascade of events within the brain’s cells, often described as a neurometabolic crisis. This involves a mass depolarization of neurons, leading to an uncontrolled influx of ions. The brain expends a tremendous amount of energy attempting to restore this ionic balance, creating a temporary state where energy demand exceeds supply.
This cellular overactivity and energy depletion directly disrupts the brain regions that govern the sleep-wake cycle. Structures like the reticular activating system (RAS) in the brainstem, which promotes wakefulness, can become dysregulated, leading to persistent hyperarousal. The hypothalamic-pituitary-adrenal (HPA) axis, which manages the body’s stress response, is also activated. This activation leads to a sustained release of stress hormones that oppose the transition to sleep.
The brain’s internal clock, regulated by the suprachiasmatic nucleus, relies on a precise balance of neurochemicals. A concussion can impair the production or signaling of key sleep regulators, such as melatonin, leading to lower evening levels. The injury can also affect hypocretin (orexin), a neuropeptide that maintains wakefulness. This impact can vary, sometimes resulting in excessive daytime sleepiness or fragmented nighttime sleep.
Poor sleep also impairs the glymphatic system, which acts as the brain’s waste clearance mechanism. This system is most active during deep sleep, flushing out metabolic byproducts that accumulate during wakefulness. When sleep is disturbed, the clearance of these waste products is reduced. This reduction can impede the brain’s recovery process and prolong symptoms.
Common Post-Concussion Sleep Issues
Difficulties with sleep after a concussion manifest in several distinct ways. One common form is sleep initiation insomnia, the inability to fall asleep quickly at the beginning of the night. This is frequently a result of neurological hyperarousal that leaves the brain in a state of alert wakefulness.
Another frequent complaint is maintenance insomnia, characterized by waking up frequently during the night or waking up too early and being unable to return to sleep. This fragmentation results in poor sleep quality, as the individual spends less time in deep, restorative stages. The increased time spent in lighter sleep cycles diminishes the brain’s opportunity for healing and repair.
A shift in the body’s natural rhythm, known as a Circadian Rhythm Sleep-Wake Disorder, is also common, affecting approximately one-third of individuals with persistent symptoms. This disorder often presents as a delayed sleep-wake phase, where the body tends to fall asleep and wake up significantly later than desired. This misalignment with schedules compounds the feeling of fatigue and daytime sleepiness.
Conversely, some individuals experience post-traumatic hypersomnia, feeling excessively sleepy and requiring much more sleep than usual, particularly immediately following the injury. Even after extended periods of sleep, many report non-restorative sleep. They wake up feeling unrefreshed and continue to struggle with daytime fatigue.
Secondary Factors Affecting Sleep
Several secondary factors beyond the direct neurological impact can significantly worsen post-concussion sleep problems. Headaches and neck pain are prominent physical symptoms that make finding a comfortable position difficult, leading to frequent nocturnal awakenings. This constant physical discomfort acts as a powerful arousal trigger, preventing the sustained deep sleep necessary for recovery.
Anxiety and mood changes are intertwined with sleep disruption, creating a self-perpetuating cycle of sleeplessness and psychological distress. Worry about the injury, fear of not recovering, or frustration can lead to conditioned arousal. In this state, the bed or bedroom becomes associated with wakefulness and anxiety, which can be more challenging to overcome than the initial physical injury.
Certain medications prescribed during recovery can unintentionally interfere with sleep architecture. Over-the-counter pain relievers containing caffeine can be stimulating, while some prescription medications for mood or pain can fragment natural sleep cycles. Patients should also be cautious about common over-the-counter sleep aids containing antihistamines. These compounds can impair memory and cognitive function, which is detrimental to a recovering brain.
Changes in daily routine, such as reduced physical activity and excessive napping, also blur the distinction between wakefulness and sleep. This lack of structure weakens the natural homeostatic drive for sleep at night. When the brain does not expend sufficient energy or receive clear cues about the difference between day and night, it struggles to regulate the sleep cycle effectively.
Strategies for Improving Sleep During Recovery
The most effective approach to managing post-concussion sleep problems focuses on non-pharmacological methods, known as Cognitive Behavioral Therapy for Insomnia (CBT-I). A foundational element of this therapy is strict sleep hygiene, which involves creating a sleep-conducive environment. This means ensuring the bedroom is dark, quiet, and cool, ideally below 70 degrees Fahrenheit, to facilitate the natural drop in body temperature that precedes sleep.
Maintaining a consistent sleep-wake schedule, even on weekends, is necessary to help reset the body’s disrupted circadian rhythm. It is recommended to avoid daytime naps after the initial acute phase of the injury. If a nap is necessary, it should be limited to 20 to 30 minutes and taken before mid-afternoon to preserve the homeostatic sleep drive for the night.
Stimulus control is a behavioral technique that addresses the learned association between the bed and wakefulness. If sleep does not occur within about twenty minutes, one should leave the bedroom. Engage in a quiet, non-stimulating activity in dim light until feeling drowsy again, then return to bed. This technique helps reinforce the idea that the bed is exclusively for sleep.
Limiting exposure to bright light, especially the blue light emitted by screens, for at least an hour before bedtime is important because this light suppresses the release of melatonin. Avoiding stimulants like caffeine and nicotine for many hours before bed, as well as minimizing alcohol, is strongly advised. These substances can severely disrupt the quality and continuity of sleep.
If sleep difficulties persist beyond a few weeks or severely impact daytime function, consulting a healthcare provider or a sleep specialist is recommended. They can provide a comprehensive assessment and potential treatment, such as formal CBT-I or short-term, medically managed sleep aids.