The Circadian System Is Vulnerable to Concussion The suprachiasmatic nucleus (SCN) is the master clock. Located in the hypothalamus, the SCN coordinates the body's circadian rhythms. It receives light input from the retina and synchronizes hormones, body temperature, alertness, and sleep-wake cycles. Concussion can damage the SCN or its connecting pathways, disrupting the entire circadian system (Wickwire et al., 2016). The pineal gland produces melatonin. Located near the base of the brain, the pineal gland responds to SCN signals to produce melatonin at night. Concussion can affect pineal function or its signaling pathways, reducing melatonin production. The melatonin deficiency disrupts sleep onset, sleep quality, and the antioxidant function melatonin provides. Retinal ganglion cells provide light input. Specialized retinal cells (intrinsically photosensitive retinal ganglion cells) detect light and signal the SCN. Concussion affects these cells and their connections. The reduced light signaling impairs the daily circadian synchronization that healthy rhythm requires. The Symptoms of Circadian Disruption Delayed sleep onset. Patients lie awake for hours despite exhaustion. Sleep does not arrive when expected. The circadian signal to sleep is delayed or weakened. Many patients describe being tired all day then unable to sleep at night. Fragmented sleep. Frequent awakenings throughout the night. Difficulty returning to sleep after waking. Total sleep time may be adequate but quality is poor. The circadian system normally maintains continuous sleep; disrupted circadian function produces the fragmented pattern. Inverted energy patterns. Many PCS patients become evening-energetic and morning-exhausted, reversing typical patterns. The disrupted circadian rhythm produces a phase delay where the body's daily energy peak shifts later. The pattern is biological, not behavioral. Daytime sleepiness despite night sleep. Even with adequate hours, daytime alertness is reduced. The circadian alertness signal that should peak during the day is weakened. The pattern persists even when patients sleep 9-10 hours. Mood and cognitive changes. Circadian disruption produces depression, irritability, and cognitive impairment independent of other PCS factors. The mood and cognitive symptoms often improve substantially when circadian rhythm restores. Mobility Support for Circadian Restoration JME 155 Diaphragmatic breathing at consistent times reinforces the daily rhythm that circadian restoration requires. Morning breathing (within 30 minutes of waking) signals daytime activation. Evening breathing (within 60 minutes of bed) signals sleep preparation. The consistent timing supports rhythm restoration. 10 breaths each session. JME 14 Chin tucks address the cervical contribution to sleep disruption. Cervical tension produces pain micro-arousals that fragment sleep. Pre-sleep chin tucks reduce the cervical baseline that disrupts overnight sleep. 10 repetitions with 5-second holds, included in evening routine. JME 1 Cervical rotation maintains the mobility that supports comfortable sleep positioning. Stiff necks force restricted sleep postures that produce overnight pain awakenings. Regular rotation maintains positioning options. 10 repetitions each direction during the day. JME 150 Thoracic rotation supports the breathing capacity needed for sleep quality. Stiff thoracic spines restrict breathing during sleep, fragmenting the architecture. Daily thoracic mobility supports the breathing that quality sleep requires. 8 repetitions per direction. Start your 3-day free trial for circadian-restoration mobility programming. The Circadian Restoration Protocol Step 1: Morning bright light exposure. 20-30 minutes of bright outdoor light within 60 minutes of waking. This is the single most powerful circadian intervention. The light signal through the eyes resets the SCN. On cloudy days or during winter, use a 10,000 lux light therapy box. The morning timing matters; afternoon bright light is less effective. Step 2: Consistent wake time. Same wake time every day, including weekends. Variable wake times prevent circadian entrainment. Pick a sustainable time and maintain it. The consistency teaches the SCN when the daily cycle begins. Step 3: Evening light reduction. Dim indoor lights to 50% or less starting 2-3 hours before bed. Eliminate blue light through f.lux, night shift, or blue-blocking glasses. The reduced evening light allows melatonin production to begin. Bright evening light suppresses melatonin and delays sleep onset. Step 4: Consistent bedtime. Same bedtime every night. Together with the consistent wake time, this defines the sleep window the SCN can synchronize to. The combination of consistent timing and light cycle restores rhythm faster than either alone. Step 5: Consider melatonin supplementation. 0.3-1 mg of melatonin 2-3 hours before bed (not at bedtime). The timing differs from typical recommendations because the goal is rhythm restoration, not sedation. The low dose mimics natural production. Higher doses commonly used (3-10 mg) often produce side effects without additional benefit. Daily Movement to Support Rhythm JME 3 Lateral cervical flexion as part of consistent morning and evening routines reinforces daily rhythm. The routine consistency supports circadian entrainment. 8 repetitions per side with 15-second holds, twice daily. JME 42 Shoulder circles support the morning activation that healthy circadian rhythm produces. The brief movement at consistent morning time reinforces the daytime activation signal. 10 repetitions each direction, morning. JME 15 Cervical extension supports cerebral blood flow that healthy circadian function requires. The exercise contributes to the morning activation and evening preparation routines. 8 repetitions, twice daily. JME 151 Lateral side bends with breathing serve as the integrative pre-sleep exercise. The combination of mobility, breathing, and parasympathetic activation prepares the body for sleep onset. 8 repetitions per side, evening. Restore your circadian rhythm with simplmobility's rhythm-support programming. Common Mistakes That Prevent Restoration Variable weekend schedules. Sleeping in on weekends produces "social jet lag" that resets the SCN backward. The Monday morning struggle reflects the weekend disruption. Maintaining the schedule on weekends is essential, even when extended sleep is needed (go to bed earlier rather than sleeping in). Evening exercise. Vigorous exercise within 3 hours of bed delays sleep onset. The body temperature rise and sympathetic activation interfere with sleep preparation. Move exercise to morning or early afternoon for circadian benefit. Late caffeine. Caffeine half-life is extended after concussion. Even 2 PM coffee can affect sleep onset. Move caffeine to morning only during recovery. Switch to decaf afternoon options. Alcohol use. Alcohol disrupts circadian rhythm beyond its sleep effects. Even moderate consumption shifts the rhythm and fragments sleep. Eliminate during active circadian restoration. How long until my circadian rhythm restores? With consistent protocol implementation, most patients see substantial improvement in 2-4 weeks. Full restoration typically takes 6-8 weeks. The early changes feel subtle (sleeping slightly earlier, waking slightly more refreshed). The cumulative effect of weeks of consistency produces dramatic improvement. Should I take prescription sleep medications? Generally not as a first approach. Sleep medications produce sedation but do not restore circadian rhythm. They often produce daytime grogginess that worsens PCS symptoms. Use circadian protocol first. Medications may be appropriate for severe insomnia that does not respond to protocol, with provider guidance. Why am I energetic at night and exhausted in the morning? Your circadian rhythm has phase-delayed. The body's daily activation pattern has shifted later. The morning fatigue and evening alertness reflect this shift. The morning light exposure protocol specifically addresses this phase delay. Most patients see the pattern correct within 2-4 weeks. References Wickwire, E. M., et al. (2016). Sleep, sleep disorders, and mild traumatic brain injury: A review. Chest, 149(5), 1296-1312. PubMed Patricios, J. S., et al. (2023). Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport, Amsterdam, October 2022. British Journal of Sports Medicine, 57(11), 695-711. PubMed