Concussion After a Blow to the Head: Red Flags, Sleep and Recovery

After a blow to the head, first check for the danger signs below; if there are none, watch the person closely. A responsible adult should stay with them for the first 24 hours. Current guidance does not require waking them on a schedule to sleep — what matters is that someone is nearby and they can be woken. Most children with concussion feel better within 2–4 weeks (CDC).

When to see a doctor

Now — emergency (999 in the UK, 911 in the US, 112 in the EU):

knocked out and has not come round, cannot stay awake or is hard to wake;
a seizure;
vomiting more than once;
a severe headache or one that keeps getting worse, especially despite pain relief (IFRC);
pupils of different sizes, double vision or other problems with sight or hearing;
slurred speech, weakness or numbness, trouble walking, keeping balance, understanding, speaking or writing;
confusion, not recognising people or places, unusual behaviour, restlessness or agitation;
clear fluid or blood from the ears or nose, bruising behind the ears, a black eye with no injury to the eye;
a fall from more than 1 metre or five stairs, or a high-speed impact such as a car crash (NHS, UK);
a wound with something in it or a dent in the head;
a baby under 1 with a bruise, swelling or large cut on the head (NHS); a baby who cries inconsolably or will not feed (CDC).

If the person does not respond and is not breathing normally (occasional gasps are not normal breathing — Resuscitation Council UK), call an ambulance and start CPR.

Today — to the emergency department without delay (NICE NG232, UK): any loss of consciousness, however short; not remembering the injury or what came before or after it; a headache that has not let up since the injury; any vomiting — the UK NHS suggests calling 111 after a single vomit; blood thinners (anticoagulants, or antiplatelet drugs other than aspirin alone) or a bleeding disorder; previous brain surgery; a high-energy injury; being drunk or on drugs at the time; concern about abuse. If no one can stay with the person at home, NICE advises considering a hospital visit. In the UK, for a child under 5, call 111 for advice (NHS).

Routine: symptoms that last more than 2 weeks — see a GP (NHS).

What is happening

Typical symptoms versus warning signs. After a knock to the head, headache, nausea, dizziness and tiredness are common and usually fade. The list above is different: these are the signs that guidelines treat as an emergency. Such signs can appear hours later, which is why watching for the first day matters.

First aid cannot diagnose concussion. There is no validated concussion score for non-professionals, so anyone suspected of concussion should be checked by a medic (European Resuscitation Council, 2021).

Where "wake every 2 hours" came from. Doctors used to advise waking children regularly after a head injury; "now they recommend letting kids rest and sleep as needed" (KidsHealth). The NHS says you or your child "do not need to stay awake if you're tired", with an adult nearby for the first 24 hours; CDC advises letting a child "sleep as usual". The American Red Cross calls sleep "generally considered safe" once a doctor has checked the person, and a doctor may ask for wake-ups. The NICE checks every half hour, then hourly, then every 2 hours are a hospital observation schedule, not advice for home. What still matters at home: if the person is very hard to wake or cannot stay awake, call an ambulance.

What to do

Stay with them for 24 hours (NHS; NICE).
Rest, but not in bed for days. For up to 2 days, relative rest with light activity such as walking is fine, with less screen time for the first 48 hours (Concussion in Sport Group, 2023).
No alcohol until they feel better; sleeping pills only if a doctor prescribed them (NHS).
Pain relief: for headache, paracetamol as directed on the leaflet (NHS) — see paracetamol or ibuprofen and, for children, doses by weight. Do not take aspirin or ibuprofen without a doctor's advice. Guidance differs here: the American Red Cross advises against painkillers because they can mask symptoms. Do not give children medicines without asking a doctor (CDC).
Do not drive until fully recovered, and do not drive yourself to hospital (NHS).
Work or school: go back when feeling better (NHS).

Return to sport goes in steps, each lasting at least 24 hours and usually completed within a month; students return fully to learning before unrestricted sport (Concussion in Sport Group, 2023). In the UK, no contact sport for at least 3 weeks, and children should avoid rough play for a few days (NHS). Children return to sport with a doctor's clearance (CDC).

When this is not the case

Babies and toddlers cannot describe symptoms — watch feeding, crying and alertness.
Blood thinners raise the stakes: go to the emergency department even if the person seems fine (NICE).
Related: a faint followed by a fall — what to do if someone faints; a seizure; after a car accident; ringing or hearing loss after a head injury is an emergency — protect your hearing.

Sources

Checked: 27 September 2026