Reliable study of more than 1,200 Japanese adults with high blood pressure found that people who slept for less than 7.5 hours each night were more likely to suffer a heart attack or stroke or die of cardiac arrest over a 4-year period. Man women who slept less than 7.5 hours per night experienced a 68% higher risk of heart attacks, cardiac arrest or strokes.

“Short sleepers” — people who fail to have a blood-pressure dip that normally occurs overnight were at even higher risk.

Waiting for latest study to appear in PubMed.gov

Other studies …

Eguchi K, Ishikawa J, Hoshide S, Pickering TG, Schwartz JE, Shimada K, Kario K. Night Time Blood Pressure Variability Is a Strong Predictor for Cardiovascular Events in Patients With Type 2 Diabetes.  Am J Hypertens. 2008 Oct 2.

Scientists studied 35 men and 36 women aged between 18 and 45. Some were exposed to radiation that exactly mimicked mobile phone radiation; others were placed in precisely the same conditions, but without radiation exposure.

The research showed that using the handsets before bed caused people to take longer to reach deeper stages of sleep and and in shorter intervals. Exposure to 884 MHz wireless disrupted sleep periods that involve the body’s ability to repair damage suffered during the day.

The sleep disturbance can lead to mood and personality changes, ADHD-like symptoms, depression, lack of concentration and poor academic performance, grouchiness, difficulty concentrating, and hyperactivity and behavior problems in children.

About half of the people in the study believed themselves to be “electrosensitive”, with claims of symptoms such as headaches and impaired cognitive function from mobile phone use, but they proved unable to tell if they had been exposed to the radiation in the test.

Published by the Massachusetts Institute of Technology’s Progress in Electromagnetics Research Symposium and funded by the Mobile Manufacturers Forum, representing the main handset companies.

Pubmed abstract not found.

See also …

Hillert L, Akerstedt T, Lowden A, Wiholm C, Kuster N, Ebert S, Boutry C, Moffat SD, Berg M, Arnetz BB. The effects of 884 MHz GSM wireless communication signals on headache and other symptoms: An experimental provocation study. Bioelectromagnetics. 2007 Nov 28

Sleep is the state of natural rest observed throughout the animal kingdom — all mammals and birds, and in many reptiles, amphibians, and fish. In humans, other mammals, and many other animals that have been studied, such as fish, birds, ants, and fruit-flies,  regular sleep is necessary for survival. The capability of arousal from sleep is a protective mechanism that is also necessary for health and survival.

UNDER CONSTRUCTION …

Sleep is generally characterized by a reduction in voluntary body movement, decreased to little reaction to external stimuli, loss of consciousness, reduction in audio receptivity, an increased rate of anabolism (the synthesis of cell structures), and a decreased rate of catabolism (the breakdown of cell structures).

In mammals, the measurement of eye movement during sleep is used to divide sleep into two categories or phases: rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Each category has a distinct set of associated physiological, neurological and psychological features.

Sleep occurs in cycles of REM and NREM phases. In humans, this cycle is approximately 90 to 120 minutes. Each phase may have a distinct physiological function. Drugs such as alcohol and sleeping pills can suppress certain stages of sleep (see Sleep deprivation). This can result in a sleep that exhibits loss of consciousness but does not fulfill its physiological functions.

In the REM phase, the brain is active and the body inactive, and this is when most dreaming occurs. REM sleep is characterized by an electroencephalography (EEG) that has low voltage and mixed frequency — similar in appearance to the wakeful EEG. During REM sleep there is loss of skeletal muscle tone, and an active sympathetic nervous system. Also during REM sleep our muscles are paralyzed so that we don’t act out our dreams.

In the NREM sleep phase, the body is active and the brain is inactive, and there is relatively little dreaming. Non-REM encompasses four stages; stages 1 and 2 are considered ‘light sleep’, and 3 and 4 ‘deep sleep’. They are differentiated silence, or “drowsy sleep”. Associated with the onset of sleep during N1 may be sudden twitches and hypnic jerks. These are normal, as is an increased instance of flatulence[citation needed]. Other people may also experience hypnagogic hallucinations during this stage, which can be more troublesome to the subject. During N1 the subject loses some muscle tone, and conscious awareness of the external environment.

Stage N2, is characterized by “sleep spindles” (12 to 16 Hz) and “K-complexes.” During this stage the electromyography (EMG) lowers, and conscious awareness of the external environment disappears. This occupies 45 to 55% of total sleep.

In Stage N3, the delta waves, also called delta rhythms (0.5 to 4 Hz) make up less than 50% of the total wave-patterns. This is considered part of the slow-wave sleep (SWS) and functions primarily as a transition into stage N4. Overall it occupies 3 to 8% of total sleep time. This is the stage in which night terrors, bed wetting, sleepwalking, and sleep-talking occur.

In Stage N4, delta-waves make up more than 50% of the wave-patterns. Stages N3 and N4 are the deepest forms of sleep; N4 is effectively a deeper version of N3, in which the deep-sleep characteristic, such as delta-waves, are more pronounced.[1]

UNDER CONSTRUCTION …

An altered gene, named “after hours” or Afh, is a variant of a gene called Fbxl3, which had not been known to have any relationship to control of the body clock that keeps our metabolism, digestion and sleep patterns in tune with the rising and setting of the sun.

Instead of following the typical 24 hour pattern, a discovery showed that some mice had body clocks that stretched to up to a 27 hour day. Closer study of the DNA from the mice revealed that those on a 27-hour-cycle had the after hours or Afh version of the Fbxl3 gene — a large family of genes that controls the breakdown of specific proteins within body cells. Specifically, the mutation, a Cys358Ser substitution in Fbxl3, an F-box protein with leucine-rich repeats, results in long free-running rhythms of about 27 hours.

The internal body clocks of mice with the after hours gene run on a longer cycle than mice that have a normal copy of the gene with the 24 hour schedule. The body clock consists of interlocked cycles of proteins that wax and wane in cells. A key protein in the loop called CRY had a delayed rate of degradation.

Also noted, the circannual body calendar is reset every summer, when increased light inhibits the production of melatonin — important in the relationship to mood.

Sofia I. H. Godinho, Elizabeth S. Maywood, Linda Shaw, Valter Tucci, Alun R. Barnard, Luca Busino, Michele Pagano, Rachel Kendall, Mohamed M. Quwailid, M. Rosario Romero, John O’Neill, Johanna E. Chesham, Debra Brooker, Zuzanna Lalanne, Michael H. Hastings, and Patrick M. Nolan. The After-Hours Mutant Mouse Reveals a Role for Fbxl3 in Determining Mammalian Circadian Period. Published online 26 April 2007 [DOI: 10.1126/science.1141138] (in Science Express Reports).

Science