Sleep is a Life or Death Habit for the Warfighter
Written by JD Mata
MS, CSCS,*D, TSAC-F,*D, RSCC
Bottom Line Up Front
LACK OF SLEEP HAS BEEN ASSOCIATED WITH INCREASED SUICIDE RISK.
This article is a bit science heavy. If you want the meat and potatoes, skip down to the next section: Psychosocial Impacts of Disordered Sleep.
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Physiological Sleep Management
Human sleep is rhythmic in nature and revolves around direct light exposure to the eyes (9), keeps within a cycle of about 24-hrs (4), but is susceptible to changes in response to external “non-photic” stimuli, internal perceptions of those stimuli, eating habits, hydration, and many other variables (2, 26).
Each person exhibits internal variation in their sleep/wake rhythms and these “chronotypes” are strongly influenced by genetics, early life exposures (19) and possibly the region, i.e. latitude, from which they originate (5,18).
It has been frequently stated that the desired sleep duration for most people should be roughly 7 to 9-hrs per night (12), with some interpersonal variances. Failure to achieve recommended sleep times can have negative short and long-term health and performance effects on humans, especially those who serve in military occupations (15).
The 24hr human circadian clock is intimately linked to the function of the suprachiasmatic nuclei (SCN), also referred to as the “master internal pacemaker”, which is located within the hypothalamus region of the brain. Light, which enters the eyes via the retina, is received directly by the SCN and enables molecular pathways to process forward until their own rates of transcription begin to feedback and inhibit themselves, at a rate of about every 24hrs. These molecular pathways act within the SCN to signal directly to major function centers within the brain and indirectly to the peripheral tissues to synchronize the various bodily functions around this 24hr light/dark rhythm (4). Again, these cycles are also influenced by interactions that are not light/dark based, but the SCN is the most significant influence throughout on sleep patterns and failure to maintain a consistent sleep routine promotes stress-induced body function disruption.
Disturbance of this normal 24-hr sleep cycle can lead to an increase in hypothalamic-pituitary-adrenal-axis (HPA axis; stress response control center) signaling which can hinder the factors that contribute to falling asleep on time, the length and quality of sleep cycles observed, and hormone activity during sleep (4, 6). When the HPA axis is stimulated, usually in the response to physical and mental/emotional stress, the pituitary gland releases adrenocorticotropic hormone (ACTH) which then acts upon the adrenal cortex then synthesizes and releases cortisol. Chronic HPA axis stimulation and high cortisol levels have been linked to insomnia, mild depression, and psychotic major depression (25), reduced insulin sensitivity and carbohydrate tolerance, and possibly hypertension or pre-hypertension.
Chronic stress response has also been linked with higher resting blood concentrations of certain pro-inflammatory cytokines; interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNFα) comprise known markers of inflammation which play a role in sleep regulation in the human body (28).
Sticking to a well-regulated sleep/wake rhythm allows these inflammatory compounds to flux within their normal 24hr cycles, whereas disrupted sleep has been shown to drive more chronic elevations of these molecules and lead to the development or proliferation of sleep disorders, mood disturbances, and metabolic syndrome.
In addition, Bollinger et al. (2009) stated the body may adapt a dysfunctional immune response from disrupted sleep patterns in the long-term; “clock desynchrony in the leukocyte subpopulations to chronic sleep disturbances will promote immune related diseases such as autoimmunity, allergy, and tumors.”
It is highly evident that warfighters who seek to maintain healthy lives, successful personal relationships, and highly functional careers need to maintain sleep rhythms (when possible) and be provided resources or time by their organizations to mitigate the effects of sleep-loss under operational conditions outside of their control.
Psychosocial Impacts of Disordered Sleep
The failure to maintain adequate amounts of sleep can create physiological distress which manifests in a horde of cognitive, psychological, and behavioral symptoms that may impact health and mission effectiveness of warfighters well beyond their immediate life in service.
Foster (2020) reported the following signs and symptoms associated with inadequate sleep patterns in humans:
Increased time required to feel alert after waking
Daytime sleepiness
Moodiness
Irritability
Inability to maintain concentration
Self-selecting impulsive behavior(s)
Craving caffeine and/or sugary food and drinks
Worry
Anxiety
Depressive symptoms
These symptoms have also been reported to induce a “feed-forward” loop, where the poor sleep regimen induces symptoms that cause more physiological and psychological stress -- thus more impaired sleep and even more symptoms. In these cases, a larger magnitude, a greater amount, or maintenance of current symptoms occur - further feeding the detrimental impacts of inadequate sleep and can produce psychosocial behaviors that are not compatible with personal health, healthy personal relationships, military operations, and organizational performance in the short and long term.
Lack of sleep has been associated with increased suicide risk, lifetime assessment of suicidal ideation or attempt, frequency of ideation during last 12-months, verbalizing ideation to another, and reported likelihood of a future suicide attempt(s) (3).
Let me state that again:
LACK OF SLEEP HAS BEEN ASSOCIATED WITH INCREASED SUICIDE RISK.
In a study which surveyed 1,700 college aged males and females (18-29yrs), similar ages to those seen in a typical warfighter, 83% of respondents who met the classification criteria to be considered at risk for suicide were also considered sleep-deprived – reporting less than 6 hours per night.
Becker et al. (2018) also reported a 2.7x increase in reported suicide risk for those individuals who were communicating the following:
Poor subjective sleep quality
Poor sleep latency
Poor sleep duration
Habitual sleep deficiency
Sleep disturbance
Use of sleep medication
Daytime dysfunction due to self-perceived sleep inadequacy
Symptoms of insomnia have also been shown as a top individual predictor of suicidal ideation in a subset of 300+ service members who were referred to major U.S. Army Medical centers for severe suicidality, even when other known contributors such as substance abuse, post-traumatic stress, and anxiety are factored out of the analysis (20).
These self-reported symptoms of insomnia were also associated with self-reported suicide attempts at the one-month follow-up in these service members, but this finding only trended toward statistical significance. Interestingly, baseline reports of suicidal ideations did not predict symptoms of insomnia at the one-month follow-up. This suggests that self-reported insomnia feeds forward into suicidal ideation and potentially suicide attempts, but suicidality does not necessarily increase symptoms of insomnia. Though, these findings are to be considered with care when applied to a general military population, as these subjects were undergoing active mental health intervention stemming from suicide attempts and/or ideations.
Regardless, these conclusions add depth to the importance of PRIORITIZING sleep at the command-level, not as a convenience, but as a life-or-death matter.
Decision Making
When choices outside of one’s own mortality are considered, sleep deprivation still has a negative effect on our individual decision-making ability.
Olsen, Pallesen, and Eid (2010) reported a correlation between disturbed sleep and the inability to make “moral judgements” while in a command-and-control situation following five nights of sleeping an average of 2.5 hours in military field training conditions. The officer trainees who were sleep deprived exhibited a decrement of sound judgment, which has been linked with higher-level cognition in relation to the ideas of “justice and equality” (29). They also reported higher average scores on the well-validated “Stanford Sleepiness Scale'' compared to those who were not sleep deprived.
Killgore et al. (2007) reported similar findings in a study of 26 active-duty military personnel. Reaction times involving “Personal Moral Judgements”, or situations where the health or safety of another party, or parties, was dependent on the infliction of harm to a specific and identifiable individual were slower following 53-hours of continuous wakefulness. The subjects had to decide if an outcome to this type of scenario was “appropriate” or “not appropriate”.
These associations between sleep and impaired decision-making have been frequently documented in the literature for over 20-years (1, 13, 16) and can be mitigated through thoughtful leadership and compassionate decision making from organizational stakeholders.
“Potentially grave decisions are in-line with warfighter duties and hold severe consequences which may have no solutions if negatively influenced by habitual poor sleep. ”
Moral reasoning and ethical decision making can become a major contributor to self- and peer-perceived leadership and in-role performance (30), especially when outcomes involve the health, safety, and well-being of others (31). For this reason, it is vital that warfighter sleep must be PROTECTED as a vital resource by military leaders when the conditions allow. Failure to do so, especially after viewing this evidence, could extend past innocent neglect into willful negligence, with the life of everyone under their command or responsibility serving as collateral damage.
Key Takeaways
Sleep revolves around a 24hr internal cycle that is largely regulated by getting light exposure into the eyes early in the day.
Failure to sleep 7-9hrs per night can result in disturbance of our natural physiological cycles - which can lead to a “feed-forward loop” where symptoms of poor sleep lead to even worse sleep.
The “feed forward” of that poor sleep cycle can increase the likelihood of warfighters displaying signs of depression, anxiety, and other clinical psychological conditions.
Those who are chronically sleep deprived have a reduced capacity to make sound judgments in their own lives and decisions that affect the life and safety of others.
Chronic sleep deprivation has been shown to be directly linked to increased suicidality in young adults, increased suicidal ideations and future suicide attempts in military AND civilian populations – independent of other lifestyle factors.
* Extensive list of References provided below JD’s bio
JD MATA
Linkedin: jd-mata
JD Mata is a 10-year United States Air Force veteran with multiple deployments supporting Operations Iraqi and Enduring Freedom, as well as Combined Joint Task Force – Horn of Africa.
Following his honorable discharge in 2014, he has been involved in Strength & Conditioning as a coach and researcher in the military, law-enforcement, college, pro, and Olympic human performance communities which has resulted in multiple peer-reviewed scientific journal articles.
Over that time, JD has amassed 19 years of experience in the general and specific development of tactical and athletic skills that contribute to success and survivability in competition and in life. Now pursuing his PhD, JD spends his free time exploring nature with his dog Lex, playing recreational sports, training for the sport of Olympic weightlifting, and enjoying watching his three beautiful nieces growing into strong, confident young women.
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