Publications

2023

Engert L, Haack. Immune, neuroendocrine, and metabolic functions in insomnia disorder. In: Kushida C, editor. Encyclopedia of Sleep and Circadian Rhythms. Vols. 3. 2nd ed. Elsevier; 2023. pp. 113–122.
Substantial evidence supports that insomnia prospectively increases risks for developing a wide range of diseases, including cardiovascular, metabolic, neurodegenerative, autoimmune, carcinogenic diseases, and pain disorders. The mechanisms underlying increased disease risks in individuals suffering from insomnia are an active area of research and involve dysregulations of multiple biological systems, including immune, neuroendocrine, and metabolic processes. Dysregulations in these physiological domains as they have been observed in insomnia disorder will be reviewed and their potential in mediating increased disease risk will be discussed.

2022

Besedovsky L, Dang R, Engert LC, Goldstein MR, Devine JK, Bertisch SM, Mullington JM, Simpson N, Haack M. Differential effects of an experimental model of prolonged sleep disturbance on inflammation in healthy females and males. PNAS Nexus. 2022;1(1):pgac004.
Sleep disturbances, including disrupted sleep and short sleep duration, are highly prevalent and are prospectively associated with an increased risk for various widespread diseases, including cardiometabolic, neurodegenerative, chronic pain, and autoimmune diseases. Systemic inflammation, which has been observed in populations experiencing sleep disturbances, may mechanistically link disturbed sleep with increased disease risks. To determine whether sleep disturbances are causally responsible for the inflammatory changes reported in population-based studies, we developed a 19-day in-hospital experimental model of prolonged sleep disturbance inducing disrupted and shortened sleep. The model included delayed sleep onset, frequent nighttime awakenings, and advanced sleep offset, interspersed with intermittent nights of undisturbed sleep. This pattern aimed at providing an ecologically highly valid experimental model of the typical sleep disturbances often reported in the general and patient populations. Unexpectedly, the experimental sleep disturbance model reduced several of the assessed proinflammatory markers, namely interleukin(IL)-6 production by monocytes and plasma levels of IL-6 and C-reactive protein (CRP), presumably due to intermittent increases in the counterinflammatory hormone cortisol. Striking sex differences were observed with females presenting a reduction in proinflammatory markers and males showing a predominantly proinflammatory response and reductions of cortisol levels. Our findings indicate that sleep disturbances causally dysregulate inflammatory pathways, with opposing effects in females and males. These results have the potential to advance our mechanistic understanding of the pronounced sexual dimorphism in the many diseases for which sleep disturbances are a risk factor.

2021

STUDY OBJECTIVES: Prior studies have suggested a benefit of yoga for alleviating sleep disturbance; however, many studies have had methodological limitations. This trial study aimed to extend that literature by including an active sleep hygiene (SH) comparison. METHODS: Participants aged 25-59 with a primary complaint of sleep onset insomnia lasting at least six months were block randomized to 8-week Kundalini Yoga or SH intervention, both consisting of initial 60-minute instruction and weekly check-ins. Daily sleep diaries and questionnaires were collected at baseline, throughout intervention, and at 6-month follow-up. Data were analyzed using linear mixed models (N=20 in each group). RESULTS: Participant ratings of the interventions did not significantly differ. SH improved several diary and questionnaire outcomes, however, yoga resulted in even greater improvements corresponding to medium-to-large between-group effect sizes. Total sleep time increased progressively across yoga treatment (d=0.95, p=.002), concurrent with increased sleep efficiency (SE; d=1.36, p<.001) and decreased sleep onset latency (SOL; d=-1.16, p<.001), but without changes in pre-sleep arousal (d=-0.30, p=.59). Remission rates were also higher for yoga compared to SH, with ≥80% of yoga participants reporting average SOL<30 minutes and SE>80% at 6-month follow-up. For over 50% of yoga participants, the insomnia severity index decreased by at least 8 points at end of treatment and follow-up. CONCLUSIONS: Yoga, taught in a self-care framework with minimal instructor burden, was associated with self-reported improvements above and beyond an active sleep hygiene comparison, sustained at 6-month follow-up. Follow-up studies are needed to assess actigraphy and polysomnography outcomes, as well as possible mechanisms of change. CLINICAL TRIAL REGISTRATION: Yoga as a Treatment for Insomnia (ClinicalTrials.gov, NCT00033865).
Yang H, Baltzis D, Bhatt V, Haack M, Meier-Ewert H, Gautam S, Veves A, Mullington J. Macro- and microvascular reactivity during repetitive exposure to shortened sleep: sex differences. Sleep. 2021;44(5). doi:10.1093/sleep/zsaa257
Epidemiological studies have reported strong association between sleep loss and hypertension with unknown mechanisms. This study investigated macrovascular and microcirculation changes and inflammatory markers during repetitive sleep restriction. Sex differences were also explored. Forty-five participants completed a 22-day in-hospital protocol. Participants were assigned to, (1) eight-hour sleep per night (control), or (2) sleep restriction (SR) condition: participants slept from 0300 to 0700 h for three nights followed by a recovery night of 8-h sleep, repeated four times. Macrocirculation assessed by flow mediated dilation (FMD) and microcirculation reactivity tests were performed at baseline, last day of each experimental block and during recovery at the end. Cell adhesion molecules and inflammatory marker levels were measured in blood samples. No duration of deprivation (SR block) by condition interaction effects were found for FMD, microcirculation, norepinephrine, cell adhesion molecules, IL-6 or IL-8. However, when men and women were analyzed separately, there was a statistical trend (p = 0.08) for increased IL-6 across SR blocks in women, but not in men. Interestingly, men showed a significant progressive (dose dependent) increase in skin vasodilatation (p = 0.02). A novel and unexpected finding was that during the recovery period, men that had been exposed to repeated SR blocks had elevated IL-8 and decreased norepinephrine. Macrocirculation, microcirculation, cell adhesion molecules, and markers of inflammation appeared to be resistant to this model of short-term repetitive exposures to the blocks of shortened sleep in healthy sleepers. However, men and women responded differently, with women showing mild inflammatory response and men showing more vascular system sensitivity to the repetitive SR.
Mullington J, Cunningham T, Haack M, Yang H. Causes and Consequences of Chronic Sleep Deficiency and the Role of Orexin. Front Neurol Neurosci. 2021;45:128–138. doi:10.1159/000514956
Sleep is one of the pillars of health. Experimental models of acute sleep loss, of chronic partial sleep deprivation, and of sleep fragmentation in healthy sleepers are helpful models of sleep deficiency produced by insufficient sleep duration, sleep timing, and sleep disorders. Sleep deficiency is associated with changes in markers associated with risk for disease. These include metabolic, inflammatory, and autonomic markers of risk. In addition, sleep disruption and sleep deficits lead to mood instability, lack of positive outlook, and impaired neurobehavioral functioning. On a population level, insufficient sleep is associated with increased risk for hypertension and diabetes. Sleep disturbance is very common, and about half the population will report that they have experienced insomnia at some time in their lives. Approximately 10% of the population describe daytime impairment due to sleep disturbance at night, consistent with a diagnosis of insomnia disorder. The hypothalamic neuropeptides, orexin-A and orexin-B, act through G-protein-coupled receptors (orexin-1 and orexin-2 receptors). Dual and selective orexin-2 receptor antagonists have shown efficacy in inducing sleep in men and women with insomnia disorder by accelerating sleep onset and improving sleep efficiency and total sleep time. Further study comparing these medications, in short- and longer-term use models, is recommended. Greater understanding of comparative effects on mood, neurobehavioral, and physiological systems will help determine the extent of clinical utility of dual versus selective orexin receptor antagonists.

2020

Goldstein M, Lewin R, Allen J. Improvements in well-being and cardiac metrics of stress following a yogic breathing workshop: Randomized controlled trial with active comparison. J Am Coll Health. 2020:1–11. doi:10.1080/07448481.2020.1781867
Objective: Compare two distinct psychosocial stress-management workshops.Participants: Undergraduate and graduate students (n = 69 for analysis, completed April 2017).Methods: Participants were randomized to one of two workshops (Sudarshan Kriya Yoga, SKY; Wisdom On Wellness, WOW), matched in terms of duration, group size, etc. Outcomes were questionnaires and psychophysiological response to laboratory stress induction at pre, post, and 3-month follow-up.Results: SKY and WOW participants demonstrated similar workshop ratings and retention rates. SKY demonstrated greater improvements on a number of self-report measures relative to WOW, including perceived stress, sleep, social connectedness, distress, anxiety, depression, conscientiousness, self-esteem, and life satisfaction. Both groups improved in terms of heart rate measures of stress reactivity, however, these outcomes were partially related to changes in resting values at post-workshop and follow-up.Conclusions: These findings offer insight into unique patterns of change between yogic breathing, acceptance-based approaches to stress management versus cognitively based approaches.
Rodriguez-Seijas C, Fields E, Bottary R, Kark S, Goldstein M, Kensinger E, Payne J, Cunningham T. Comparing the Impact of COVID-19-Related Social Distancing on Mood and Psychiatric Indicators in Sexual and Gender Minority (SGM) and Non-SGM Individuals. Front Psychiatry. 2020;11:590318. doi:10.3389/fpsyt.2020.590318
Empirical evidence demonstrates mental health disparities between sexual and gender minority individuals (SGM) compared with cisgender heterosexual individuals. SGM individuals report elevated rates of emotional distress, symptoms related to mood and anxiety disorders, self-harm, and suicidal ideation and behavior. Social support is inversely related to psychiatric symptoms, regardless of SGM status. The COVID-19 pandemic-with its associated limited social interactions-represents an unprecedented period of acute distress with potential reductions in accessibility of social support, which might be of particular concern for SGM individuals' mental well-being. In the present study, we explored the extent to which potential changes in mental health outcomes (depressive symptoms, worry, perceived stress, positive and negative affect) throughout the duration of the pandemic were related to differences in perceptions of social support and engagement in virtual social activity, as a function of SGM status. Utilizing a large sample of US adults (N = 1,014; 18% reported SGM status), we assessed psychiatric symptoms, perceptions of social isolation, and amount of time spent socializing virtually at 3 time windows during the pandemic (between March 21 and May 21). Although SGM individuals reported greater levels of depression compared with non-SGM individuals at all 3 time points, there was no interaction between time and SGM status. Across all participants, mental health outcomes improved across time. Perceived social isolation was associated with poorer mental health outcomes. Further, time spent engaging in virtual socialization was associated with reduced depression, but only for those in self-reported quarantine. We discuss these results in terms of the nature of our sample and its impact on the generalizability of these findings to other SGM samples as well as directions for future research aimed at understanding potential health disparities in the face of the COVID-19 pandemic.