Most sports-related head injuries, such as concussions — which temporarily interfere with the way the brain works — are mild and allow for complete recovery.

Head injuries take time to heal. After a concussion, children should rest from both physical and mental (cognitive) activities for a day or two. They should return to activities gradually as their symptoms allow.

Some children who return to school after a concussion may require classroom adjustments, including a lighter course load or a shortened school day. If activities such as reading or jogging cause symptoms, such as headache, children should take a break. Then, they may resume the activity for shorter periods, gradually working up to pre-concussion levels as symptoms improve. A gradual return to learning and physical activity is key.

If there's any suspicion of a concussion, it's best not to return to play until symptoms improve. In other words, "If in doubt, sit it out."

Common concussion symptoms can include:

• Difficulty with thinking skills, such as memory and attention
• Dizziness
• Fatigue
• Headaches
• Irritability

Children might develop complications or delay healing if they are reinjured before a concussion has healed. Another blow to the head while the initial concussion is healing can result in longer lasting or more-severe symptoms.

Researchers continue to study other potential long-term effects of concussions. Having a concussion puts children at higher risk of having another. The effects of repeat concussions over years can multiply.

Post-concussion syndrome is a complex disorder of concussion symptoms that last longer than the usual concussion recovery period. It's unclear why some people develop post-concussion syndrome and others don't, though some risk factors have been identified. Some research suggests that having repeat concussions might increase the risk of post-concussion syndrome.

In rare cases, what is initially thought to be a concussion turns out to be a more severe brain injury with bleeding in or around the brain. Such bleeding can increase pressure on the brain and can be life-threatening.

If your child develops any of the following signs or symptoms after a head injury, seek medical attention immediately.

• Behavior changes such as agitation, confusion or restlessness
• Convulsions or seizures
• Inability to recognize people or places
• Loss of consciousness
• One pupil that is larger than the other
• Slurred speech
• Unusual behavior
• Extreme drowsiness or inability to be woken from sleep
• Vomiting
• Crying that won't stop and inability to be consoled

To protect your child from head injuries, insist on appropriate and properly fitted protective equipment — such as a helmet — during sports and other activities. However, even the best protective equipment can't prevent all concussions.

Children can have a concussion without losing consciousness. Also, a blow to the body that jars the head can result in concussion. Make sure your child's coach knows if your child has had a concussion. Your child shouldn't return to play until he or she has been cleared by a medical professional. Formal return-to-sport plans are recommended.

Signs and symptoms of a concussion may include:

• Headache or a feeling of pressure in the head
• Nausea or vomiting
• Balance problems or dizziness
• Double or blurry vision
• Sensitivity to light or noise
• Feeling fatigued, sluggish, groggy or dazed
• Difficulty paying attention
• Memory problems
• Confusion
• Slowness in understanding and responding to others
• Sleeping problems
• Mood changes and irritability
• Changes in behavior
• Changes in personality

If you think your child has a concussion, seek medical attention. Your child's doctor will determine how serious the concussion is and when it's safe for your child to return to sports, school or other activities.