Sleep is essential for maintaining both physical and mental health, but achieving restful, uninterrupted sleep is a constant struggle for many veterans. Circadian rhythm disorders disrupt the body’s natural sleep-wake cycle, making it difficult to fall, stay, or wake up at appropriate times. These disorders are pervasive among veterans due to the demanding schedules, shift work, and environmental stressors experienced during military service.

For some, circadian rhythm disturbances develop as a direct result of deployment schedules, combat-related stress, or exposure to traumatic events. Others experience these disorders as a secondary condition linked to service-connected sleep disorders such as sleep apnea, PTSD, or traumatic brain injury (TBI). Regardless of the cause, veterans suffering from sleep disorders may be able to secure VA disability benefits with the help of a nexus letter.

Common Causes of Circadian Rhythm Disorders in Veterans

Circadian rhythm disorders occur when the body’s internal clock, which regulates sleep and wakefulness, is disrupted. While anyone can develop these disorders, veterans are at a significantly higher risk due to the unique demands and experiences of military service. Below are some of the most common causes of circadian rhythm disorders among veterans.

Shift Work and Irregular Schedules

Military service often requires personnel to work unconventional hours, including night shifts, rotating schedules, and extended duty periods. These irregular sleep patterns can confuse the body’s internal clock, making it difficult to fall asleep and wake up at the appropriate times. Over time, this leads to Shift Work Sleep Disorder, a condition where the body struggles to adapt to changing work schedules, resulting in chronic fatigue, difficulty concentrating, and long-term sleep disruptions. Even after leaving the military, many veterans continue to experience sleep disturbances because their bodies have been conditioned to function on erratic sleep schedules.

Frequent Deployments and Time Zone Changes

When experiencing jet lag, most of us have the luxury of taking extra time to acclimate and realign our sleep schedules. Veterans are not offered the same opportunity to adjust to a new time zone gradually during a deployment. Their roles require immediate action, and despite the rapid change in their sleep cycle, they are required to function immediately. For veterans who have been on multiple deployments, these experiences can translate into irregular sleep schedules that permanently change the body’s circadian rhythm, leading to sleep disorders that follow them home long after their service has ended.

Exposure to Combat and Chronic Stress

The high-stress environment of combat zones can impact a veteran’s ability to regulate sleep. During active service, many military personnel develop hypervigilance, a heightened state of alertness that makes it difficult to relax or feel safe while sleeping.

Traumatic Brain Injury and Neurological Damage

Traumatic Brain Injury is a service-connected condition that can directly interfere with the brain’s ability to regulate sleep-wake cycles. Since the brain plays a critical role in controlling circadian rhythms, any damage to the neurological pathways responsible for sleep regulation can lead to long-term disturbances that require medical intervention.

Chronic Pain and Medication Use

Many veterans suffer from chronic pain conditions related to musculoskeletal injuries, nerve damage, or post-surgical complications. Pain can make it difficult to fall asleep and stay asleep, leading to inconsistent sleep patterns. Additionally, many medications prescribed for pain management, depression, or anxiety—such as opioids, antidepressants, and stimulants—can interfere with the body’s circadian rhythm. Some medications cause drowsiness during the day, while others lead to nighttime alertness, further disrupting normal sleep-wake cycles.

Types of Circadian Rhythm Sleep Disorders

Circadian rhythm sleep disorders occur when the body’s internal clock is misaligned with the natural day-night cycle, causing difficulties in maintaining a regular sleep schedule. Veterans are particularly susceptible to these disorders due to shift work, deployments, combat stress, and service-related injuries. Below are the most common types of circadian rhythm sleep disorders that may be connected to military service.

Shift Work Sleep Disorder

Many service members work irregular schedules, including night shifts, rotating shifts, and extended duty periods. These schedules force the body to stay awake when it would naturally be sleeping, leading to Shift Work Sleep Disorder (SWSD).

Delayed Sleep Phase Syndrome

Delayed Sleep Phase Syndrome (DSPS) is characterized by a consistent delay in the sleep-wake cycle, meaning a person naturally falls asleep much later than socially or professionally acceptable times. Veterans with DSPS may find themselves unable to fall asleep until the early morning hours, resulting in chronic daytime sleepiness and difficulty maintaining a traditional work schedule. This disorder is often linked to PTSD, chronic stress, and neurological changes that shift the body’s circadian rhythm later than normal.

Advanced Sleep Phase Syndrome

Advanced Sleep Phase Syndrome (ASPS) is the opposite of DSPS. In ASPS, the individual feels excessively sleepy in the early evening and wakes up much earlier than desired. Veterans with ASPS may find themselves unable to stay awake past the early evening hours and wake up before dawn, regardless of how much sleep they’ve had.

Non-24-Hour Sleep-Wake Disorder

Non-24-Hour Sleep-Wake Disorder is a condition where a person’s sleep cycle gradually shifts later each day, making it increasingly difficult to maintain a stable schedule. This disorder is common among blind veterans whose bodies are unable to process natural light cues, but it can also affect those with traumatic brain injuries or neurological conditions that impair circadian rhythm regulation.

Irregular Sleep-Wake Rhythm Disorder

Irregular Sleep-Wake Rhythm Disorder is characterized by a lack of a stable sleep schedule, where sleep occurs in fragmented episodes throughout the day and night rather than in a single, consolidated period. Veterans with TBI, PTSD, or neurodegenerative conditions are more likely to experience this disorder, as brain damage or psychological distress can prevent the body from maintaining a normal circadian rhythm. This condition can be particularly disruptive to daily functioning, making it difficult for veterans to hold steady employment, engage in social activities, or get sufficient restorative sleep.

Circadian Rhythm Disorders and Their Connection to Service-Connected Conditions

Circadian rhythm disorders often develop as a result of underlying service-connected conditions such as PTSD, TBI, sleep apnea, and chronic pain. Veterans with PTSD frequently experience hypervigilance, nightmares, and heightened anxiety, making it challenging to maintain a regular sleep schedule.

TBI can disrupt the brain’s ability to regulate sleep-wake cycles, leading to conditions like Non-24-Hour Sleep-Wake Disorder or Irregular Sleep-Wake Rhythm Disorder. Sleep apnea, a common service-connected disorder, fragments sleep and contributes to circadian misalignment. Chronic pain and medications used to manage service-related conditions further interfere with sleep stability, causing delayed or irregular sleep patterns. Metabolic and gastrointestinal conditions, such as obesity, diabetes, and GERD, can also be linked to disrupted circadian rhythms. Veterans experiencing these issues may qualify for VA disability benefits if they can establish a service connection, typically with medical evidence and a VA nexus letter.

Filing a VA Disability Claim for Circadian Rhythm Disorders

Veterans seeking VA disability benefits for circadian rhythm disorders must demonstrate that their condition is service-connected. The first step is obtaining a formal diagnosis from a medical professional, often through sleep studies and evaluations by a neurologist or sleep specialist. Because circadian rhythm disorders are often secondary to conditions like PTSD, TBI, sleep apnea, or chronic pain, veterans should document any related diagnoses that may strengthen their claim.

To establish a service connection, veterans must submit medical evidence linking their sleep disorder to military service. This can include service treatment records, VA medical records, and private doctor evaluations. A VA nexus letter from a qualified medical provider can be crucial in explaining how the disorder developed due to service-related factors.

Once the claim is filed, the VA evaluates the severity of symptoms and their impact on daily life. Veterans can appeal if their claim is denied by providing additional medical evidence or seeking legal representation to strengthen their case.

The Role of VA Nexus Letters for Circadian Rhythm Disorders

A VA nexus letter is essential for establishing the connection between a circadian rhythm disorder and military service. Written by a medical professional, this letter explains how the condition is linked to service-related factors such as PTSD, TBI, shift work, or deployments. It should provide a clear medical opinion, supported by clinical evidence, that the disorder is “at least as likely as not” caused or worsened by military service. A strong nexus letter strengthens a veteran’s claim by bridging the gap between medical records and VA eligibility criteria, increasing the likelihood of securing disability benefits for sleep-related conditions.

Learn How Elite Medical Review Associates Can Help

Unfortunately, securing a VA nexus letter is not always as easy as it sounds. Many doctors are unwilling or unable to evaluate your condition and write a letter on your behalf. Without one, your chances of a successful claim are drastically reduced.

Elite Medical Review Associates can help by matching you with a medical professional in the sleep disorder field. Their expertise could be what is needed to build a successful claim. Call today to learn more.