For decades, the standard advice after a head injury was to stay awake or be woken up frequently by a caregiver. This created a widespread belief that sleeping with a concussion was dangerous, stemming from the fear of missing a serious complication while the person was asleep. Medical understanding has significantly evolved. A concussion is now defined as a mild traumatic brain injury (TBI) that causes a temporary, functional disturbance to the brain.
Understanding Concussions
A concussion is not typically a structural injury, such as a physical tear or bleeding visible on a standard brain scan. Instead, it is a complex physiological event resulting from the rapid acceleration or deceleration of the head, causing the brain to move quickly within the skull. This forceful movement triggers a cascade of ionic, metabolic, and physiologic disturbances at the cellular level.
The primary result is a functional disruption that temporarily impairs normal brain communication. Following the injury, the brain experiences an energy crisis, where there is an increased demand for glucose but a simultaneous decrease in cerebral blood flow. This metabolic imbalance causes common, short-term symptoms like confusion, dizziness, and mental fogginess.
The Historical Misconception
The fear surrounding sleep after a head injury originated when diagnostic tools were limited. Doctors lacked modern imaging technologies like CT scans and MRIs to quickly rule out severe internal injuries. The primary concern was missing the signs of a much more serious injury, such as an epidural or subdural hematoma, which involves bleeding in or around the brain.
This type of severe brain bleed causes a slow, progressive increase in pressure inside the skull. As this pressure builds, a patient’s neurological status deteriorates, leading to extreme drowsiness, unresponsiveness, and potentially coma. Because sleeping people cannot report worsening symptoms, the historical advice was to keep the person awake to monitor for these life-threatening changes.
Current Medical Guidance on Sleep
Current medical guidance states that sleep is not only safe but also an important part of the concussion recovery process. The brain actively uses sleep to repair itself and restore the metabolic balance disrupted by the injury. Denying sleep can hinder recovery and may worsen symptoms like headaches and irritability.
For a person diagnosed with a mild concussion who has been medically assessed and does not exhibit any immediate “red flag” symptoms, controlled sleep is encouraged. A medical professional might recommend a caregiver check in a few times during the first night to ensure the person can be easily roused and is responsive, rather than waking them hourly.
Recovery also depends on cognitive rest, especially in the initial days following the injury. This involves temporarily avoiding activities that require intense mental focus, such as reading, using computers, or doing schoolwork. This period of reduced mental demand allows the brain to conserve energy and dedicate resources to cellular repair.
Warning Signs Requiring Immediate Attention
While sleep is generally safe and beneficial for a mild concussion, certain symptoms indicate a more severe traumatic brain injury requiring immediate emergency medical attention. These “red flag” signs suggest the injury is likely structural, involving bleeding or significant swelling.
If any of the following symptoms occur, the person should be taken to the emergency room immediately:
- Inability to wake up or significant, increasing drowsiness beyond normal fatigue.
- Any change in pupil size, such as one pupil being larger than the other.
- A headache that continuously worsens and does not go away.
- Repeated episodes of vomiting.
- Seizures or convulsions.
- Slurred speech or profound confusion that rapidly worsens.
- Drainage of clear fluid or blood from the ears or nose.