A concussion is a brain injury resulting from a bump, blow, or jolt to the head that temporarily alters normal brain function. This type of traumatic brain injury can lead to various symptoms affecting physical well-being, cognitive skills, emotions, and sleep patterns. Difficulty sleeping is a common and often frustrating experience reported by many individuals after a concussion.
The Brain’s Immediate Response
Immediately following a concussion, the brain undergoes complex physiological changes impacting sleep regulation. An “energy crisis” occurs as the brain’s demand for repair energy increases, while the supply of glucose, its primary fuel, decreases.
The initial mechanical force causes rapid ion shifts, requiring ion pumps to consume large amounts of glucose for balance. Reduced cerebral blood flow hinders glucose delivery, exacerbating this energy deficit. This metabolic mismatch can lead to mitochondrial dysfunction, deepening the energy crisis.
Neuroinflammation, the brain’s immune response to injury, often worsens outcomes and contributes to sleep disturbances. Inflammation can disrupt sleep regulation, and poor sleep can intensify neuroinflammation, creating a detrimental feedback loop.
Concussions disrupt the balance of neurotransmitters regulating sleep and wakefulness. An excessive release of glutamate, an excitatory neurotransmitter, is linked to sleep disruption after mild traumatic brain injury.
Conversely, levels of gamma-aminobutyric acid (GABA), the brain’s main inhibitory neurotransmitter, may be affected; decreased levels are associated with insomnia. Sleep-regulating hormones like melatonin, crucial for the sleep-wake cycle, and hypocretin (orexin) and histamine, which promote wakefulness, can also be impacted. Reduced levels of these substances can lead to poor sleep quality, decreased restorative sleep, or excessive daytime sleepiness.
Disruption of Sleep-Wake Regulation
Beyond the immediate injury response, a concussion can interfere with the body’s natural sleep-wake cycle and organized sleep stages. Brain injury can disrupt the circadian rhythm, the body’s internal clock, leading to difficulty falling asleep or maintaining sleep throughout the night.
The injury can also alter sleep architecture, the distinct phases of sleep including REM and non-REM stages. Individuals with concussions often experience fragmented sleep, characterized by frequent awakenings. This fragmentation reduces overall sleep efficiency and time in restorative sleep stages.
Some individuals experience insomnia, struggling to initiate or maintain sleep, while others develop hypersomnia, an excessive need for sleep. Reduced REM sleep, important for cognitive function and emotional processing, has been observed. This compromised sleep quality means the brain does not get the restorative benefits needed for healing.
The Vicious Cycle of Poor Sleep and Concussion Symptoms
Inability to achieve restorative sleep after a concussion often creates a negative feedback loop, worsening symptoms and challenging recovery. Poor sleep can intensify headaches, increase cognitive fog, and impair memory. This cognitive impairment makes daily tasks difficult, leading to frustration and heightened anxiety.
Poor sleep impacts emotional regulation, leading to increased irritability, mood swings, or anxiety. These emotional difficulties make it harder to relax and fall asleep, perpetuating the cycle. Insufficient sleep hinders the brain’s capacity for repair and recovery, as sleep clears waste products, repairs damaged cells, and consolidates memories.
Poor sleep quality is directly linked to a longer duration of concussion symptoms. Pain and low mood, common after a concussion, can make it difficult to fall asleep. Overwhelming fatigue might lead to frequent daytime naps, inadvertently disrupting the natural sleep drive needed for consolidated nighttime sleep.
When to Seek Professional Guidance
While some sleep disturbances after a concussion may resolve, seek medical attention if difficulties are severe and persistent, significantly impacting daily life or hindering recovery. This includes severe insomnia that does not improve or excessive daytime sleepiness interfering with normal functioning.
Seek immediate medical attention for a worsening headache, slurred speech, new weakness or numbness, repeated vomiting, seizures, or inability to wake up. If symptoms worsen or do not resolve after 10 to 14 days, medical guidance is advisable. A professional can assess the sleep disturbance and rule out other conditions like sleep apnea or narcolepsy.