Interactions between evening and nocturnal cortisol secretion and sleep parameters in patients with severe chronic primary insomnia

Heart rate variability and daytime functioning in insomniacs and normal sleepers: preliminary results

OBJECTIVES

This study examined the differences in heart rate variability (HRV) and daytime functioning between insomniacs and normal sleepers.

METHODS

All participants underwent an interview, a medical examination, and a sleep measurement protocol during which they wore an actigraph and logged a sleep diary for a 7-day period to verify their eligibility. Included in the study were 18 insomniacs and 21 normal sleepers. During a laboratory session, these participants completed four paper-pencil tests of sleepiness, anxiety, fatigue, and concentration difficulty and the Wisconsin Card Sorting Test. Resting HRV was recorded under paced breathing.

RESULTS

Neither did insomniacs experience cognitive impairment nor did they experience excessive daytime sleepiness compared with normal sleepers. However, insomniacs experienced higher frequency of fatigue [effect size (ES)=1.14, P=.002] compared with normal sleepers. There was also a trend toward higher trait anxiety score (ES=0.62) and concentration difficulty (ES=0.59) in insomniacs than in normal sleepers. Although a tendency toward lower resting high- frequency (HF) HRV (ES=-0.57) in insomniacs than in normal sleepers was noted, neither the resting low-frequency (LF) HRV nor the LF/HF ratio were different between groups. Subjective sleep estimates correlated to self-reported daytime consequences such as fatigue and concentration difficulty but not cognitive function. On the contrary, objective sleep estimates correlated to problem-solving/conceptualization and learning but not self-reported daytime consequences.

CONCLUSIONS

Insomniacs are not sleepier during the day than normal sleepers. However, they may experience such a daytime symptom as fatigue although cognitive function remains unimpaired.

Can electrons act as antioxidants? A review and commentary

A previous study demonstrated that connecting the human body to the earth during sleep (earthing) normalizes the daily cortisol rhythm and improves sleep. A variety of other benefits were reported, including reductions in pain and inflammation. Subsequent studies have confirmed these earlier findings and documented virtually immediate physiologic and clinical effects of grounding or earthing the body. It is well established, though not widely known, that the surface of the earth possesses a limitless and continuously renewed supply of free or mobile electrons as a consequence of a global atmospheric electron circuit. Wearing shoes with insulating soles and/or sleeping in beds that are isolated from the electrical ground plane of the earth have disconnected most people from the earth's electrical rhythms and free electrons. The most reasonable hypothesis to explain the beneficial effects of earthing is that a direct earth connection enables both diurnal electrical rhythms and free electrons to flow from the earth to the body. It is proposed that the earth's diurnal electrical rhythms set the biological clocks for hormones that regulate sleep and activity. It is also suggested that free electrons from the earth neutralize the positively charged free radicals that are the hallmark of chronic inflammation. A relationship between cortisol and inflammation was established in the pioneering work of H. Selye published in the 1950s. Current biomedical research has led to an inflammation hypothesis that is establishing chronic inflammation as the culprit behind almost every modern chronic illness. The research summarized here and in subsequent reports provides a basis for a number of earthing technologies that restore and maintain natural electrical contact between the human body and the earth throughout the day and night in situations where going barefoot on the earth is impractical. It is proposed that free or mobile electrons from the earth can resolve chronic inflammation by serving as natural antioxidants.

Which symptoms predict recurrence of depression in women treated with maintenance interpersonal psychotherapy?

BACKGROUND

Even low levels of residual symptoms are known to increase the risk of relapse and early recurrence of major depression. It is not known if ongoing psychotherapy lessens this risk. We therefore examined the impact of persistent symptoms, including mood, insomnia, and anxiety symptoms, on time to recurrence in women receiving maintenance interpersonal psychotherapy (IPT-M) for recurrent depression.

METHODS

We analyzed data on 131 women aged 20-60 from a 2-year randomized trial of weekly versus twice-monthly versus monthly IPT-M. Participants achieved remission with IPT alone (n=99) or IPT plus sequential antidepressant medication (n=32). Medications were tapered before starting maintenance treatment. Residual symptoms were assessed with the Hamilton Rating Scale for Depression (HRSD; total score and subscales); insomnia was also assessed in 76 women with the Pittsburgh Sleep Quality Index (PSQI). Data analyses used Cox proportional hazards regression models.

RESULTS

Neither overall burden of residual symptoms (HRSD total score), nor HRSD mood and anxiety subscale scores predicted recurrence during ongoing IPT-M. In contrast, persistent insomnia measured both by the HRSD-17 insomnia subscale and the PSQI predicted recurrence. Women with persistent insomnia who required sequential pharamacotherapy had the highest recurrence rate (65%) compared to women requiring sequential treatment without insomnia (13%), or women who had recovered with IPT alone but had persistent insomnia (21%) or no insomnia (18%).

CONCLUSIONS

Persistent insomnia following the recovery from an episode of recurrent major depression is associated with increased risk of recurrence despite maintenance psychotherapy, particularly for those withdrawn from antidepressant medication.

Neurochemical regulation of sleep

This review summarizes recent developments in the field of sleep regulation, particularly in the role of hormones, and of synthetic GABA(A) receptor agonists. Certain hormones play a specific role in sleep regulation. A reciprocal interaction of the neuropeptides growth hormone (GH)-releasing hormone (GHRH) and corticotropin-releasing hormone (CRH) plays a key role in sleep regulation. At least in males GHRH is a common stimulus of non-rapid-eye-movement sleep (NREMS) and GH and inhibits the hypothalamo-pituitary adrenocortical (HPA) hormones, whereas CRH exerts opposite effects. Furthermore CRH may enhance rapid-eye-movement sleep (REMS). Changes in the GHRH:CRH ratio in favor of CRH appear to contribute to sleep EEG and endocrine changes during depression and normal ageing. In women, however, CRH-like effects of GHRH were found. Besides CRH somatostatin impairs sleep, whereas ghrelin, galanin and neuropeptide Y promote sleep. Vasoactive intestinal polypeptide appears to be involved in the temporal organization of human sleep. Beside of peptides, steroids participate in sleep regulation. Cortisol appears to promote REMS. Various neuroactive steroids exert specific effects on sleep. The beneficial effect of estrogen replacement therapy in menopausal women suggests a role of estrogen in sleep regulation. The GABA(A) receptor or GABAergic neurons are involved in the action of many of these hormones. Recently synthetic GABA(A) agonists, particularly gaboxadol and the GABA reuptake inhibitor tiagabine were shown to differ distinctly in their action from allosteric modulators of the GABA(A) receptor like benzodiazepines as they promote slow-wave sleep, decrease wakefulness and do not affect REMS.

CHRONIC INSOMNIA AND STRESS SYSTEM

SynopsisIn insomnia, which is a very common sleep disorder, objective sleep measures, EEG activity, physiologic findings, HPA axis activity and inflammation markers suggest that it is not a state of sleep loss, but a disorder of hyperarousal present both during the night and the daytime. Several psychological and physiological factors contribute to the onset and perpetuation of insomnia, such as anxious-ruminative personality traits, stressful events, age-related sleep homeostasis weakening mechanisms, menopause and biologic - genetic diathesis of CNS hyperarousal. The therapeutic approach in insomnia should be multidimensional reducing the overall emotional and physiologic hyperarousal and its underlying factors present throughout the 24-h sleep/wake period.

Impaired declarative memory consolidation during sleep in patients with primary insomnia: Influence of sleep architecture and nocturnal cortisol release

BACKGROUND

A central cognitive function of sleep is to consolidate newly acquired memories for long-term storage. Here, we investigated whether the overnight consolidation of declarative memory in patients with chronic sleep disturbances is impaired, owing to less slow wave sleep (SWS) and an increased cortisol release.

METHODS

Polysomnographic recordings, serum cortisol concentrations, and overnight memory consolidation in 16 patients with primary insomnia were compared with those of 13 healthy control subjects.

RESULTS

Patients displayed distinctly less overnight consolidation of declarative memory (p < .05), which was significantly correlated with SWS in the control subjects (r = .69) but with rapid eye movement (REM) sleep in the patients (r = .56), who had a diminished amount of SWS (p < .05). Increased cortisol levels in the middle of the night were associated with impaired retrieval of declarative memory after sleep for both control subjects (r = -.52) and patients (r = -.46).

CONCLUSIONS

Primary insomnia is associated with a diminished sleep-related consolidation of declarative memory. Efficient overnight consolidation of declarative memory is associated with high amounts of SWS and low serum cortisol levels during the early part of the night. Where SWS is decreased, REM sleep might play a partly compensatory role in the consolidation of declarative memory.

Roles of peptides and steroids in sleep disorders

A bidirectional interaction exists between the electrophysiological and neuroendocrine components of sleep. The first is represented by the nonrapid eye movement sleep (NREMS) and rapid eye movement sleep (REMS) cycles, the latter by distinct patterns of the secretion of various hormones. Certain hormones (neuropeptides and steroids) play a specific role in sleep regulation. Changes in their activity contribute to the pathophysiology of sleep disorders. A reciprocal interaction of the peptides growth hormone-releasing hormone (GHRH) and corticotropin-releasing hormone (CRH) plays a key role in sleep regulation. GHRH promotes growth hormone secretion and, at least in males, NREMS, whereas CRH impairs NREMS, promotes REMS and stimulates the secretion of adrenocorticotropic hormone and cortisol. Changes in the CRH:GHRH ratio in favor of CRH contribute to impaired sleep, elevated cortisol secretion and blunted GH levels during depression and normal aging. However, in women, GHRH exerts CRH-like effects. Galanin, ghrelin and neuropeptide Y are other sleep-promoting peptides, whereas somatostatin impairs sleep. A decline of orexin activity causes narcolepsy. In addition to CRH overactivity, hypercortisolism appears to be involved in the pathophysiology of sleep- electroencephalogram (EEG) changes in depression. Various neuroactive steroids exert specific effects on sleep. The changes of sleep EEG in women after the menopause are related to the decline of estrogen and progesterone. Furthermore, sleep-EEG changes in dwarfism, acromegaly, Addison's disease, Cushing's disease, brain injury, sleep apnea syndrome, primary insomnia, prolactinoma and dementia appear to be related to changes in the activity of peptides and steroids.

Neurophysiological aspects of primary insomnia: Implications for its treatment

Insomnia has usually been studied from a behavioral perspective. Somatic and/or cognitive conditioned arousal was shown to play a central role in sleep complaints becoming chronic, and was used as a starting point for the development of treatment modalities. The introduction of the neurocognitive perspective, with its focus on cortical or CNS arousal, has given rise to a renewed interest in the neurophysiological characteristics of insomnia. Recent research, using quantitative EEG, neuroimaging techniques and the study of the microstructure of sleep, suggests a state of hyperarousal with a biological basis. Furthermore, insomnia might not be restricted to sleep complaints alone because it appears to be a 24-h disorder, affecting several aspects of daytime functioning as well. These new findings have implications for the treatments used and indicate that a focus on cortical or CNS arousal should be pursued. As such, the use of EEG neurofeedback, a self-regulation method based on the paradigm of operant conditioning, might be a promising treatment modality. Preliminary results for insomnia and successful applications for other disorders suggest that this treatment can have the necessary stabilizing effects on the EEG activity, possibly resulting in a normalizing effect on daytime as well as nighttime functioning.

Burnout and risk of cardiovascular disease: evidence, possible causal paths, and promising research directions

Burnout is characterized by emotional exhaustion, physical fatigue, and cognitive weariness, resulting from prolonged exposure to work-related stress. The authors review the accumulated evidence suggesting that burnout and the related concept of vital exhaustion are associated with increased risk of cardiovascular disease and cardiovascular-related events. The authors present evidence supporting several potential mechanisms linking burnout with ill health, including the metabolic syndrome, dysregulation of the hypothalamic-pituitary-adrenal axis along with sympathetic nervous system activation, sleep disturbances, systemic inflammation, impaired immunity functions, blood coagulation and fibrinolysis, and poor health behaviors. The association of burnout and vital exhaustion with these disease mediators suggests that their impact on health may be more extensive than currently indicated.

Increased nocturnal interleukin-6 excretion in patients with primary insomnia: a pilot study

The aim of the present study was to investigate whether there is a difference in evening/nocturnal interleukin-6 (IL-6) serum excretion in patients with primary insomnia compared to controls. We hypothesized that in insomniac patients, the excretion of evening/nocturnal IL-6 is enhanced, like observed in aged adults and after sleep deprivation in healthy subjects. We studied IL-6 serum concentrations in 11 patients (two males and nine females) with primary insomnia and 11 age and gender-matched healthy controls. Sleep was monitored polysomnographically for three consecutive nights. The measurement of IL-6 (from 19:00 h to 09:00 h) in 2-h intervals were performed prior to and during the last laboratory night. Polysomnographically determined sleep parameters and subjective ratings of sleep demonstrated clear-cut impairments of sleep in the insomniac group. Nocturnal IL-6 secretion was significantly increased (p<.05) in insomniac patients for the whole measurement period (mean area under the curve+/-SD: 27.94+/-14.15 pg/ml x 2h) compared to controls (16.70+/-7.64 pg/ml x 2h). Total IL-6 secretion correlated inversely with subjectively perceived sleep quality and amount of slow wave sleep in the insomniac patients. Amount of Wake Time correlated positively with IL-6 excretion in insomniacs. The results of the present study demonstrate significantly increased nocturnal IL-6 secretion in insomniacs. It might be speculated that chronic primary insomnia with polysomnographically documented sleep impairments activates the production of IL-6 analogous to sleep deprivation studies in healthy subjects. This might also implicate a higher risk for inflammatory and cardiovascular diseases in patients with chronic insomnia.

The biologic effects of grounding the human body during sleep as measured by cortisol levels and subjective reporting of sleep, pain, and stress

OBJECTIVES

Diurnal cortisol secretion levels were measured and circadian cortisol profiles were evaluated in a pilot study conducted to test the hypothesis that grounding the human body to earth during sleep will result in quantifiable changes in cortisol. It was also hypothesized that grounding the human body would result in changes in sleep, pain, and stress (anxiety, depression, irritability), as measured by subjective reporting.

SUBJECTS AND INTERVENTIONS

Twelve (12) subjects with complaints of sleep dysfunction, pain, and stress were grounded to earth during sleep for 8 weeks in their own beds using a conductive mattress pad. Saliva tests were administered to establish pregrounding baseline cortisol levels. Levels were obtained at 4-hour intervals for a 24-hour period to determine the circadian cortisol profile. Cortisol testing was repeated at week 6. Subjective symptoms of sleep dysfunction, pain, and stress were reported daily throughout the 8-week test period.

RESULTS

Measurable improvements in diurnal cortisol profiles were observed, with cortisol levels significantly reduced during night-time sleep. Subjects' 24-hour circadian cortisol profiles showed a trend toward normalization. Subjectively reported symptoms, including sleep dysfunction, pain, and stress, were reduced or eliminated in nearly all subjects.

CONCLUSIONS

Results indicate that grounding the human body to earth ("earthing") during sleep reduces night-time levels of cortisol and resynchronizes cortisol hormone secretion more in alignment with the natural 24-hour circadian rhythm profile. Changes were most apparent in females. Furthermore, subjective reporting indicates that grounding the human body to earth during sleep improves sleep and reduces pain and stress.

Sleep disturbances are correlated with decreased morning awakening salivary cortisol

Morning and evening salivary cortisol levels were correlated with sleep parameters in 14 patients with primary insomnia and 15 healthy controls. Salivary cortisol was sampled immediately after awakening (T1), 15 min later (T2), and immediately before going to bed (T3) for 1 week at home. In parallel with this, subjects estimated parameters of sleep in a daily sleep log. Patients and controls were all non-smokers who did not differ regarding morning awakening time or bedtime. Cortisol after awakening was significantly decreased in primary insomnia. Salivary cortisol at the time of awakening correlated negatively with the subjective estimation of sleep quality, i.e. a low salivary cortisol level directly after awakening correlated with a higher frequency of nightly awakenings (r = -0.50), a diminished sleep quality (r = -0.34) and a decreased feeling of recovery after awakening (r = -0.35; all p < 0.05). Furthermore, awakening cortisol was negatively correlated with the Pittsburgh Sleep Quality Index (r = -0.43) and with a questionnaire on sleep-related cognitions with the subscales rumination in bed (r = -0.56 ) and focusing on sleep-related thoughts (r = -0.46; all p < 0.05).

The sleep-improving effects of doxepin are paralleled by a normalized plasma cortisol secretion in primary insomnia. A placebo-controlled, double-blind, randomized, cross-over study followed by an open treatment over 3 weeks

RATIONALE

In primary care, sedating antidepressants are often used for treating insomnia, although their underlying sleep-promoting mechanisms are only incompletely understood. Since enhanced evening and nocturnal plasma cortisol levels are supposed to maintain insomniac sleep complaints, a functional link between sleep and cortisol secretion in the mode of action of antidepressants in insomnia might be suspected.

OBJECTIVES

We therefore investigated the effects of the tricyclic antidepressant doxepin on nocturnal sleep and plasma cortisol concentration in ten patients (age 41.3+/-9.5 years) with chronic primary insomnia between 1700 hours and 0800 hours.

METHODS

Single infusions of placebo and 25 mg doxepin were applied following a double-blind, randomized cross-over design. Afterward, all patients received 25 mg doxepin p.o. for 3 weeks in an open-study design.

RESULTS

Both doxepin application forms improved sleep significantly and reduced mean cortisol levels from 9.0+/-1.7 microg/l (single placebo i.v.) to 7.5+/-1.6 microg/l (single doxepin i.v.) or 7.6+/-2.0 microg/l (subchronic doxepin p.o.). The duration of the quiescent period of the cortisol rhythm was significantly prolonged following both doxepin administrations compared with placebo.

CONCLUSIONS

The results implicate that the sleep-improving effects of doxepin are mediated at least in part by a normalization of hypothalamic-pituitary-adrenal axis functions. Although in some patients rebound insomnia and specific side effects must be considered, our findings give a further rationale for the use of antidepressants in the treatment of primary insomnia.

Nocturnal cortisol and melatonin secretion in primary insomnia

The present study investigated evening and nocturnal serum cortisol and melatonin concentrations in patients with primary insomnia to test if this clinical condition is accompanied by an increase of cortisol secretion and a simultaneous decrease of nocturnal melatonin production. Ten drug-free patients (4 males, 6 females) with primary insomnia (mean age+/-S.D.: 39.2+/-9.1 years) and 10 age- and gender-matched healthy controls participated in the study. All subjects spent three consecutive nights in the sleep laboratory with polysomnography. Measurement of cortisol and melatonin (from 19:00 h to 09:00 h) was performed prior to and during the last laboratory night. Contrary to expectation, cortisol secretion did not differ between healthy controls and insomniac patients. On the other hand, nocturnal melatonin production was significantly diminished in insomniac patients. Polysomnographically determined sleep patterns, in contrast to subjective ratings of sleep, demonstrated only minor alterations of sleep in the insomniac group. The lack of increased cortisol secretion in the patients with primary insomnia indicates that results from studies on the biological consequences of experimental sleep loss in healthy subjects cannot be applied to primary insomnia in general, especially if there are only minor objective sleep alterations. In spite of the negligible objective sleep disturbances in the present sample, nocturnal melatonin production was reduced, which tentatively suggests a role for this hormone in primary insomniacs. The pathophysiological significance of this finding is, however, still a matter of debate.