The effects of caffeinated products on sleep and functioning in the military population: A focused review

A social-ecological examination of sleep among Airmen in technical training

Inadequate sleep is an on-going risk to the health and mission readiness of U.S. Armed Forces, with estimates of sleep problems high above U.S. civilian populations. Intervening early in the career of active duty Air Force personnel (or "Airmen") with education and the establishment of healthy behaviors may prevent short and long term-detriments of sleep problems. This paper describes the results of a qualitative study seeking to understand the facilitators and barriers to achieving good sleep in a technical training school during the first year of entry into the United States Air Force. Using the social ecological framework and content analysis, three focus groups with Airmen were conducted to explore themes at the individual, social, environmental, and organizational/policy level. Overall, results indicated a cohort motivated to achieve good sleep, and also struggling with a number of barriers across each level. This paper highlights opportunities for population health interventions during technical training aimed at supporting Airmen in developing healthy sleep behaviors early in the course of their career.

Sleep loss, caffeine, sleep aids and sedation modify brain abnormalities of mild traumatic brain injury

Little evidence exists about how mild traumatic brain injury (mTBI) is affected by commonly encountered exposures of sleep loss, sleep aids, and caffeine that might be potential therapeutic opportunities. In addition, while propofol sedation is administered in severe TBI, its potential utility in mild TBI is unclear. Each of these exposures is known to have pronounced effects on cerebral metabolism and blood flow and neurochemistry. We hypothesized that they each interact with cerebral metabolic dynamics post-injury and change the subclinical characteristics of mTBI. MTBI in rats was produced by head rotational acceleration injury that mimics the biomechanics of human mTBI. Three mTBIs spaced 48 h apart were used to increase the likelihood that vulnerabilities induced by repeated mTBI would be manifested without clinically relevant structural damage. After the third mTBI, rats were immediately sleep deprived or administered caffeine or suvorexant (an orexin antagonist and sleep aid) for the next 24 h or administered propofol for 5 h. Resting state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) were performed 24 h after the third mTBI and again after 30 days to determine changes to the brain mTBI phenotype. Multi-modal analyses on brain regions of interest included measures of functional connectivity and regional homogeneity from rs-fMRI, and mean diffusivity (MD) and fractional anisotropy (FA) from DTI. Each intervention changed the mTBI profile of subclinical effects that presumably underlie healing, compensation, damage, and plasticity. Sleep loss during the acute post-injury period resulted in dramatic changes to functional connectivity. Caffeine, propofol sedation and suvorexant were especially noteworthy for differential effects on microstructure in gray and white matter regions after mTBI. The present results indicate that commonplace exposures and short-term sedation alter the subclinical manifestations of repeated mTBI and therefore likely play roles in symptomatology and vulnerability to damage by repeated mTBI.

International society of sports nutrition position stand: coffee and sports performance

Based on review and critical analysis of the literature regarding the contents and physiological effects of coffee related to physical and cognitive performance conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society:(1) Coffee is a complex matrix of hundreds of compounds. These are consumed with broad variability based upon serving size, bean type (e.g. common Arabica vs. Robusta), and brew method (water temperature, roasting method, grind size, time, and equipment).(2) Coffee's constituents, including but not limited to caffeine, have neuromuscular, antioxidant, endocrine, cognitive, and metabolic (e.g. glucose disposal and vasodilation) effects that impact exercise performance and recovery.(3) Coffee's physiologic effects are influenced by dose, timing, habituation to a small degree (to coffee or caffeine), nutrigenetics, and potentially by gut microbiota differences, sex, and training status.(4) Coffee and/or its components improve performance across a temporal range of activities from reaction time, through brief power exercises, and into the aerobic time frame in most but not all studies. These broad and varied effects have been demonstrated in men (mostly) and in women, with effects that can differ from caffeine ingestion, per se. More research is needed.(5) Optimal dosing and timing are approximately two to four cups (approximately 473-946 ml or 16-32 oz.) of typical hot-brewed or reconstituted instant coffee (depending on individual sensitivity and body size), providing a caffeine equivalent of 3-6 mg/kg (among other components such as chlorogenic acids at approximately 100-400 mg per cup) 60 min prior to exercise.(6) Coffee has a history of controversy regarding side effects but is generally considered safe and beneficial for healthy, exercising individuals in the dose range above.(7) Coffee can serve as a vehicle for other dietary supplements, and it can interact with nutrients in other foods.(8) A dearth of literature exists examining coffee-specific ergogenic and recovery effects, as well as variability in the operational definition of "coffee," making conclusions more challenging than when examining caffeine in its many other forms of delivery (capsules, energy drinks, "pre-workout" powders, gum, etc.).

Sleep, Activity, and Nutrition Among an Army Sample: Strengths, Deficits, and Demographic Differences

Sleep, activity, and nutrition (SAN) are key components in overall health, and an individual's knowledge about and self-confidence to engage in healthy SAN behaviors can have an impact on their actions. This evaluation examined SAN knowledge, self-confidence, and behaviors among U.S. Army Soldiers prior to participating in a health promotion program. Baseline surveys from participating Soldiers provide evidence in this evaluation. U.S. Army Soldiers (N = 11,485) participating in a health promotion program completed surveys. Participants completed an online survey assessing SAN knowledge, self-confidence, and behaviors (among other constructs). We examined the common patterns of SAN behaviors, the associations between them, and the differences based on gender and rank. Knowledge, self-confidence, and behaviors were correlated within each of the three SAN domains. Men reported more aerobic exercise (d = .48) and more resistance training (d = .34) per week than women. Officers reported greater self-confidence in their ability to consume a post-exercise snack (i.e., refuel; d = .38), greater refueling behaviors (d = .43), greater activity knowledge (d = .33), and greater self-confidence in their ability to achieve activity goals (d ranging from .33 to .39), compared to enlisted Soldiers. Finally, greater confidence in one's ability to achieve healthy sleep correlated with getting more sleep, both during workweek (r = .56, p < .001) and weekend (r = .25, p < .001). These baseline data support the need for health promotion of SAN behaviors among these Soldiers.

The effect of coffee and black tea consumption on sleep bruxism intensity based on polysomnographic examination

Background

Sleep bruxism (SB) is a common behavior that can result in various clinical consequences on human health. Risk factors for SB include among others emotional stress, anxiety, tobacco smoking, and excessive alcohol consumption. Coffee and black tea are among the most commonly consumed beverages worldwide. This study explores the influence of coffee and black tea consumption on bruxism intensity, as observed in polysomnographic examination.

Methods

Polysomnographic examination with simultaneous camera recording was conducted in 106 adult subjects. The results were evaluated according to guidelines set out by the American Academy of Sleep Medicine (AASM). The study group was divided according to habitual stimulant usage, as declared by the participants in a self-reported questionnaire. Four groups were identified: coffee drinkers versus non-drinkers and black tea drinkers versus non-drinkers.

Results

The bruxism episode index (BEI) was increased in coffee-drinkers as opposed to non-drinkers (4.59 ± 3.44 vs. 2.87 ± 1.50, p = 0.011). Sleep fragmentation, measured according to the arousal index, was comparable in coffee drinkers and non-drinkers. Electrolyte and lipid levels were similar in coffee drinkers and non-drinkers. Habitual black tea intake did not affect sleep architecture or bruxism intensity.

Conclusions

The study showed that habitual coffee consumption is a risk factor for the increased intensity of sleep bruxism. Neither coffee nor tea consumption is related to sleep fragmentation in habitual drinkers. Coffee and tea intake does not affect electrolyte and lipid concentrations. Caution should therefore be recommended in drinking coffee in people with sleep bruxism.

Catching up on sleep: Recent evidence on the role of sleep in substance use disorders

The objective of this editorial is to summarize the findings published in the special issue on "Sleep and Drug Abuse". The manuscripts in this issue include review articles as well as original investigations, and cover topics ranging from pre-clinical investigation to epidemiological-based clinical studies. Together, these papers provide evidence that sleep and drug abuse share a bidirectional relationship, with sleep playing a prominent role in substance use disorders. The knowledge included here can inform treatment development and future research endeavors, clearly pointing to the need for attention that focuses on sleep quality in the treatment of substance use disorders.