Sleep and circadian rhythm disruption are frequently observed in patients with psychiatric disorders and neurodegenerative disease. The abnormal sleep that is experienced by these patients is largely assumed to be the product of medication or some other influence that is not well defined. However, normal brain function and the generation of sleep are linked by common neurotransmitter systems and regulatory pathways. Disruption of sleep alters sleep-wake timing, destabilizes physiology and promotes a range of pathologies (from cognitive to metabolic defects) that are rarely considered to be associated with abnormal sleep. We propose that brain disorders and abnormal sleep have a common mechanistic origin and that many co-morbid pathologies that are found in brain disease arise from a destabilization of sleep mechanisms. The stabilization of sleep may be a means by which to reduce the symptoms of--and permit early intervention of--psychiatric and neurodegenerative disease.

Sleep and circadian rhythm disruption in psychiatric and neurodegenerative disease

Whilst exposure to vibration is traditionally regarded as perilous, recent research has focussed on potential benefits. Here, the physical principles of forced oscillations are discussed in relation to vibration as an exercise modality. Acute physiological responses to isolated tendon and muscle vibration and to whole body vibration exercise are reviewed, as well as the training effects upon the musculature, bone mineral density and posture. Possible applications in sports and medicine are discussed. Evidence suggests that acute vibration exercise seems to elicit a specific warm-up effect, and that vibration training seems to improve muscle power, although the potential benefits over traditional forms of resistive exercise are still unclear. Vibration training also seems to improve balance in sub-populations prone to fall, such as frail elderly people. Moreover, literature suggests that vibration is beneficial to reduce chronic lower back pain and other types of pain. Other future indications are perceivable.

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Vibration as an exercise modality: how it may work, and what its potential might be.

Study Objectives: Traffic noise disturbs sleep and may impair recuperation. There is limited information on single and combined effects of air, road and rail traffic noise on sleep and recuperation.
Design: Repeated measures
Setting: Polysomnographic laboratory study
Participants: 72 healthy subjects, mean ± standard deviation 40 ± 13 years, range 18-71 years, 32 male
Interventions: Exposure to 40, 80, or 120 rail, road, and/or air traffic noise events
Measurements and Results: Subjects were investigated for 11 consecutive nights, which included eight noise exposure nights and one noise-free control night. Noise effects on sleep structure and continuity were subtle, even in nights with combined exposure, most likely due to habituation and an increase in arousal thresholds both within and across nights. However, cardiac arousals did not habituate across nights. Noise exposure significantly affected subjective assessments of sleep quality and recuperation, whereas objective performance was unaffected, except for a small increase in mean PVT reaction time (+4 ms, adjusted P 3 kHz) noise event components.
Conclusions: Road, rail, and air traffic noise differentially affect objective and subjective assessments of sleep. Differences in the degree of noise-induced sleep fragmentation between traffic modes were explained by the specific spectral and temporal composition of noise events, indicating potential targets for active and passive noise control. Field studies are needed to validate our findings in a setting with higher ecologic validity.

http://www.laermorama.ch/m6_machtlaermkrank/pdf/03_Basner2011_Air,%20Road,%20Rail%20and%20Sleep.pdf

Single and combined effects of air, road, and rail traffic noise on sleep and recuperation.

Long-term spaceflight induces hypokinesia and hypodynamia, which, along microgravity per se, result in a number of significant physiological alterations, such as muscle atrophy, force reduction, insulin resistance, substrate use shift from fats to carbohydrates, and bone loss. Each of these adaptations could turn to serious health deterioration during the long-term spaceflight needed for planetary exploration. We hypothesized that resveratrol (RES), a natural polyphenol, could be used as a nutritional countermeasure to prevent muscle metabolic and bone adaptations to 15 d of rat hindlimb unloading. RES treatment maintained a net protein balance, soleus muscle mass, and soleus muscle maximal force contraction. RES also fully maintained soleus mitochondrial capacity to oxidize palmitoyl-carnitine and reversed the decrease of the glutathione vs. glutathione disulfide ratio, a biomarker of oxidative stress. At the molecular level, the protein content of Sirt-1 and COXIV in soleus muscle was also preserved. RES further protected whole-body insulin sensitivity and lipid trafficking and oxidation, and this was likely associated with the maintained expression of FAT/CD36, CPT-1, and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in muscle. Finally, chronic RES supplementation maintained the bone mineral density and strength of the femur. For the first time, we report a simple countermeasure that prevents the deleterious adaptations of the major physiological functions affected by mechanical unloading. RES could thus be envisaged as a nutritional countermeasure for spaceflight but remains to be tested in humans.

Resveratrol prevents the wasting disorders of mechanical unloading by acting as a physical exercise mimetic in the rat

Space flight is a new experience for humans. Humans adapt if not perfectly, rather well to life without gravity. There is a reductive remodeling of the musculo-skeletal system. Protein is lost from muscles and calcium from bones with anti-gravity functions. The observed biochemical and physiological changes reflect this accommodative process. The two major direct effects of the muscle loss are weakness post-flight and the increased incidence of low back ache pre- and post-flight. The muscle protein losses are compromised by the inability to maintain energy balance inflight. Voluntary dietary intake is reduced during space flight by ~20 %. These adaptations to weightlessness leave astronauts ill-equipped for life with gravity. Exercise, the obvious counter-measure has been repeatedly tried and since the muscle and bone losses persist it is not unreasonable to assume that success has been limited at best. Nevertheless, more than 500 people have now flown in space for up to 1 year and have done remarkably well. This review addresses the question of whether enough is now known about these three problems (negative energy balance, muscle loss and bone loss) for to the risks to be considered either acceptable or correctible enough to meet the requirements for a Mars mission.

Weight, muscle and bone loss during space flight: another perspective

A 6 degrees head down tilt bed rest (HDT) was used to simulate the effects of muscle unloading in space. We tested whether vibration training (VT) reduces the decrease in leg muscle volume induced by 14 days HDT. In two study phases eight healthy male subjects received both (1) HDT and VT or (2) HDT and a control intervention. Twice daily five intervals of 1 min VT were performed (20 Hz, 2-4 mm) in upright standing position followed by 1 min breaks in seated position. The control intervention included identical procedures except the vibration plate was off. Before and the day after HDT volumes of upper and lower leg muscles were measured using magnetic resonance imaging. HDT combined with control intervention caused a significant (P < 0.05) decrease in the volumes of muscles by -4 to -6.5%. VT failed to counteract the decrease in leg muscle volume induced by HDT.

20-Hz whole body vibration training fails to counteract the decrease in leg muscle volume caused by 14 days of 6° head down tilt bed rest

OBJECTIVES: Polysomnography is the gold standard for investigating noise effects on sleep, but data collection and analysis are sumptuous and expensive. We recently developed an automatic algorithm for the identification of cardiac activations associated with cortical arousals, which uses heart rate information derived from a single electrocardiogram (ECG) channel (Basner et al. 2007a). We hypothesized that cardiac arousals can be used as estimates for EEG awakenings. METHODS: Polysomnographic EEG awakenings and automatically detected cardiac activations were systematically compared using laboratory data of 112 subjects (47 male, mean ± SD age 37.9 ± 13 years), 985 nights and 23,855 aircraft noise events (ANEs). RESULTS: The overall agreement was higher in control (81.9 %) compared to noise nights (76.4 %). However, if corrected for chance expected agreement according to Landis and Koch (1977), agreement was higher in noise (к=0.60) compared to control nights (к=0.33), representing “moderate to substantial” and “fair” agreement respectively. The probability of automatically detected cardiac arousals increased monotonously with increasing maximum sound pressure levels of ANEs, exceeding the probability of EEG awakenings by up to 18.1 %. If spontaneous reactions were taken into account, exposure-response curves were practically identical for EEG awakenings and cardiac arousals. CONCLUSIONS: Automatically detected cardiac arousals can be used as estimates for EEG awakenings. This inexpensive, objective, and non-invasive method facilitates large scale field studies on the effects of traffic noise on sleep. More investigations are needed to further validate the ECG algorithm in the field and to investigate interindividual differences in its ability to predict EEG awakenings.

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Götz Kluge

Papers

20-Hz whole body vibration training fails to counteract the decrease in leg muscle volume caused by 14 days of 6° head down tilt bed rest

Aircraft noise effects on sleep: a systematic comparison of EEG awakenings and automatically detected cardiac activations.

Commercial suborbital space tourism-proposal on passenger's medical selection