Warm Feet and Sleep

Researchers writing in the medical journal Physiology and Behavior say they “present new data indicating age- and insomnia-related changes in the sleep-onset latency response to foot warming, and evaluate whether different methods of foot warming could provide an applicable strategy to address sleep complaints.”

Physiol Behav. 2007 Feb 28;90(2-3):257-66. Raymann RJ, Swaab DF, Van Someren EJ.

Skin temperature and sleep-onset latency: Changes with age and insomnia.

Throughout the 24-hour day, the occurrence of sleep and wakefulness is closely related to changes in body temperatures.

Changes in skin temperature may causally affect the ability to initiate and maintain sleep.

First, we briefly summarize a previously proposed neurobiological mechanism that couples skin temperature to sleep propensity. Next we review previous findings on the relation between skin temperature and sleep-onset latency, indicating that sleep propensity can be enhanced by warming the skin to the level that normally occurs prior to – and during – sleep. Finally, we present new data indicating age- and insomnia-related changes in the sleep-onset latency response to foot warming, and evaluate whether different methods of foot warming could provide an applicable strategy to address sleep complaints. Foot temperature manipulations included footbaths before sleep onset (1), and heatable bed socks applied either before (2) or after lights-off (3).

In adults, sleep-onset was accelerated by warm and neutral bed socks after lights-off and correlated to the increase in foot temperature. This increase was attenuated in elderly subjects. In elderly subjects without sleep difficulties, sleep onset could be accelerated with neutral bed socks after lights-off and a warm footbath prior to lights-off. In elderly insomniacs, none of the treatments accelerated sleep onset. We illustrate that elderly subjects show an attenuated increase in foot temperature after lights-off and lose the relationship between pre-sleep heat-loss activation and sleep latency. The sensitivity of sleep propensity to foot warming changes with age and is attenuated in age-related insomnia.

Sleep

Sleep and Diabetes Risk in Men Is Testosterone Also Involved?
Researchers writing in the medical journal Diabetes Care say that too little or too much sleep increases diabetes risk. The researchers say that men getting 5 to 6 hours of sleep a night were twice as likely to develop diabetes, men getting more than 8 hours were three times more likely to develop diabetes. They also noted that testosterone may be a factor in sleep on diabetes.

Poor Sleep and Cognitive Function
Researchers writing in the medical journal The Journals of Gerontology Series A: Biological Sciences and Medical Sciences say that Disturbed Sleep was related to poorer cognition.

Hot Flashes and Insomnia
Researchers writing in the Archives of Internal Medicine say: “Severe hot flashes are strongly associated with chronic insomnia in midlife women. The presence of hot flashes should be systematically investigated in women with insomnia. Treating hot flashes could improve sleep quality and minimize the deleterious consequences of chronic insomnia.”

Hot Flashes and Sleep
Researchers writing in the medical journal Menopause say that ambient temperature and REM sleep patterns effect sleep in postmenopausal women.

Warm Feet and Sleep
Researchers writing in the medical journal Physiology and Behavior say they “present new data indicating age- and insomnia-related changes in the sleep-onset latency response to foot warming, and evaluate whether different methods of foot warming could provide an applicable strategy to address sleep complaints.”

Sleep and Diabetes Risk in Men

Researchers writing in the medical journal Diabetes Care say that too little or too much sleep increases diabetes risk. The researchers say that men getting 5 to 6 hours of sleep a night were twice as likely to develop diabetes, men getting more than 8 hours were three times more likely to develop diabetes. They also noted that testosterone may be a factor in sleep on diabetes.

Highlights from the study abstract
“OBJECTIVE—Short-term partial sleep restriction results in glucose intolerance and insulin resistance. The purpose of this study was to assess the long-term relationship between sleep duration and the incidence of clinical diabetes.

RESEARCH DESIGN AND METHODS—A cohort of men from the Massachusetts Male Aging Study without diabetes at baseline (1987–1989) were followed until 2004 for the development of diabetes. Average number of hours of sleep per night was grouped into the following categories: 5, 6, 7, 8, and >8 h. Incidence rates and relative risks (RRs) were calculated for the development of diabetes in each sleep duration category. Those reporting 7 [hours] of sleep per night served as the reference group.

RESULTS—Men reporting short sleep duration (5 and 6 [hours] of sleep per night) were twice as likely to develop diabetes, and men reporting long sleep duration [more than 8 hours of sleep per night] were more than three times as likely to develop diabetes over the period of follow-up.

Elevated risks remained essentially unchanged after adjustment for age, hypertension, smoking status, self-rated health status, education, and waist circumference. (Relative Risks) were altered considerably for the two extreme sleep groups when adjusted for testosterone…suggesting that the effects of sleep on diabetes could be mediated via changes in endogenous testosterone levels.

CONCLUSIONS—Short and long sleep durations increase the risk of developing diabetes, independent of confounding factors. Sleep duration may represent a novel risk factor for diabetes.”

Yaggi HK, Araujo AB, McKinlay JB. Sleep Duration as a Risk Factor for the Development of Type 2 Diabetes. Diabetes Care 29:657-661, 2006.
Read the full abstract

Does Being Optimistic Really Lower Risk From Cardiovascular Disease in Elderly Men?
Researchers writing in the medical journal the Archives of Internal Medicine say that having an optimistic outlook, DOES lower mortality risk associated with cardiovascular disease. Read more

Poor Sleep and Cognitive Function

Blackwell T, Yaffe K, Ancoli-Israel S, Schneider JL, Cauley JA, Hillier TA, Fink HA, Stone KL. Poor Sleep Is Associated With Impaired Cognitive Function in Older Women: The Study of Osteoporotic Fractures. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 61:405-410 (2006)

Researchers writing in the medical journal The Journals of Gerontology Series A: Biological Sciences and Medical Sciences say that Disturbed Sleep was related to poorer cognition.

From the article abstract:
Background. The association between objectively measured sleep and cognition among community-dwelling elderly persons remains understudied. This observational, cross-sectional analysis examined this association.

Methods. Results are from 2932 women (mean age 83.5 years) in the Study of Osteoporotic Fractures between 2002 and 2004. Cognitive function was measured…Sleep parameters measured objectively using actigraphy included total sleep time, sleep efficiency, sleep latency, wake after sleep onset (WASO), and total nap time.

Conclusion. Objectively measured disturbed sleep was consistently related to poorer cognition, whereas total sleep time was not. This finding may suggest that it is disturbance of sleep rather than quantity that affects cognition.

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Sleep and Diabetes Risk in Men

Sleep and Risk of Fractures

Researchers writing in the Journal of the American Geriatrics Society say that long sleep and daily napping are associated with greater risk of falls and fractures in older women.

Stone KL, Ewing SK, Lui LY, Ensrud KE, Ancoli-Israel S, Bauer DC, Cauley JA, Hillier TA, Cummings SR. Self-reported sleep and nap habits and risk of falls and fractures in older women: the study of osteoporotic fractures. J Am Geriatr Soc. 2006 Aug;54(8):1177-83.

From the study abstract:

OBJECTIVES: To test the association between self-reported sleep and nap habits and risk of falls and fractures in a large cohort of older women.

DESIGN: Study of Osteoporotic Fractures prospective cohort study.

SETTING: Clinical centers in Baltimore, Maryland; Minneapolis, Minnesota; Portland, Oregon; and the Monongahela Valley, near Pittsburgh, Pennsylvania.
PARTICIPANTS: Eight thousand one hundred one community-dwelling Caucasian women aged 69 and older (mean 77.0).

MEASUREMENTS: Sleep and nap habits were assessed using a questionnaire at the fourth clinic visit (1993/94). Fall frequency during the subsequent year was ascertained using tri-annual questionnaire. Incident hip and nonspinal fractures during 6 years of follow-up were confirmed using radiographic reports. RESULTS: Five hundred fifty-three women suffered hip fractures, and 1,938 suffered nonspinal fractures. In multivariate models, women who reported napping daily had significantly higher odds of suffering two or more falls during the subsequent year (odds ratio=1.32, 95% confidence interval (CI)=1.03-1.69) and were more likely to suffer a hip fracture (hazard ratio (HR)=1.33, 95% CI=0.99-1.78) than women who did not nap daily. Those sleeping at least 10 hours per 24 hours had a higher risk of nonspinal fracture than (HR=1.26, 95% CI=1.00-1.58) and a similar but nonsignificant increased risk of hip fracture to (HR=1.43, 95% CI=0.95-2.15) those who reported sleeping between 8 and 9 hours.

CONCLUSION: Self-reported long sleep and daily napping are associated with greater risk of falls and fractures in older women. Interventions to improve sleep may reduce their risk of falls and fractures. Future research is needed to determine whether specific sleep disorders contribute to these relationships.

Bone Loss

Estradiol, Testosterone, and Hip Fractures in Men
Researchers writing in The American Journal of Medicine say “Men with low estradiol levels are at an increased risk for future hip fracture. Men with both low estradiol and low testosterone levels seem to be at greatest risk for hip fracture.”

The Importance of Strength Training Exercises in Aging
Researchers writing in the medical journal Aging Clinical and Experimental Research say that “although aerobic exercise is important in maintaining overall health, the resistance type of muscle training may be more applicable to the basic rules of bone adaptation and site-specific effects of exercise, have more favorable effects in maintaining or improving bone mass and architecture, and be safe and feasible for older people.”

DHEA, Bone Mineral Density, Older Adults
Researchers writing in the medical journal The Journal of Clinical Endocrinology & Metabolism, say that DHEA replacement therapy for one year improved hip Bone Mineral Density in older adults and spine Bone Mineral Density in older women.

Lifelong risk factors for osteoporosis and fractures in elderly women with low body mass index
Researchers writing in the medical journal Bone, evaluated the association between lifelong lifestyle factors and bone density, falls and postmenopausal fractures in elderly women with low body mass index.

Osteoporosis in Men Testosterone and Estradiol Deficiency
Researchers writing in the Journal of Clinical Endocrinology & Metabolism say that: Older men with total testosterone or estradiol deficiency were more likely to be osteoporotic. Those with osteoporosis were more likely to be total testosterone or estradiol deficient. Rapid hip bone loss was more likely in men with total testosterone deficiency.

Hip Fracture in High Risk Groups
Researchers writing in the Journal of Postgraduate Medicine say “prevention of hip fracture is still inadequate in high risk patients. Discrepancy seemed to exist in treatment frequency among different high risk groups suggesting that emphasis on prevention of osteoporosis has not been reinforced in all people at risk.”

Sleep and Risk of Fractures
Researchers writing in the Journal of the American Geriatrics Society say that long sleep and daily napping are associated with greater risk of falls and fractures in older women

Melatonin

Melatonin is secreted by the pea-sized pineal gland in the center of our brains to regulate our sleep patterns. Our bodies make it from the well known sleep inducing amino acid tryptophan.

As we age we seem to produce less melatonin and this has been suggested as one of the reasons why our aging population has difficult sleeping patterns.

The decline of melatonin centers around age 45. The decline is usually a steep one. By age 60, we produce half the melatonin we did during our twenties and by the late seventies nearly none.

What is so important about sleep?
You probably do not need a long litany of medical articles to know that it is probably a pretty good idea to get a good night’s sleep.

The researchers of sleep have broken sleep up into five different stages, Stages I and II are the “light” sleep phases, Stage III and IV are the deep sleep cycles. Dreaming occurs during Rapid Eye Movement sleep (REM). It is during level IV sleep that our body re-energizes and most importantly that the immune system is stimulated. In treating patients with chronic pain, one of the very first things we do is take a history from the patient of their sleep patterns. Melatonin helps restore good sleep architecture. Without deep Stage IV sleep, healing becomes more difficult, there is a decrease in hormones and neurotransmitters produced that can give us a great quality of life.

If regulating sleep was all that melatonin did, that would be important enough to include it in an age management program.

But research has also suggested that melatonin may contribute to the following:
– Enhances the immune system as an anti-oxidant
– Positive effect on the aging process
– Reduce blood pressure
– Improves bowel symptoms
– Decrease cholesterol
– Increase the natural killer cell activity of the immune system
– Helps reset the circadian rhythm in jet lag

Will melatonin make you live longer?
Much has been made of the possibility of melatonin being a life extender. This is based on animal studies in rats and mice that showed a 20% increase in life span. Speculation centers on melatonin’s anti-oxidant properties. No human longevity studies have been reported to date.

The negatives of melatonin
No serious side effects have been reported in the short-term, and long-term effects are unknown. Melatonin is a hormone, and as such, it should be taken under a physician’s guidance.

Other Side Effects
Headaches
Stomach upset
Insomnia
Restlessness
Depression
Strange dreams

Selected Research

Pregnenolone Research

Sleep and Memory

George O, Vallee M, Le Moal M, Mayo W. Neurosteroids and cholinergic systems: implications for sleep and cognitive processes and potential role of age-related changes Neurosteroids and cholinergic systems: implications for sleep and cognitive processes and potential role of age-related changes. Psychopharmacology (Berl). 2006 Jan 17;:1-12

Rationale: The neurosteroids pregnenolone sulfate (PREGS), dehydroepiandrosterone sulfate (DHEAS) and allopregnanolone (3alpha,5alpha THPROG) have been implicated as powerful modulators of memory processes and sleep states in young and aged subjects with memory impairment. As these processes depend on the integrity of cholinergic systems, a specific effect of neurosteroids on these systems may account for their effects on sleep and memory.

Objective: To review the evidence for a specific and differential effect of neurosteroids on cholinergic systems.

Conclusions: The specific modulation of basal forebrain and brainstem cholinergic systems by neurosteroids may account for the effects of these compounds on sleep and memory processes. To improve our understanding of the role of neurosteroids in cholinergic systems during normal and pathological aging, we need to determine whether there is specific regionalization of neurosteroids, and we need to investigate the relationship between neurosteroid concentrations in cholinergic nuclei and age-related sleep and memory impairments.

Alzheimer’s
Neurosteroid quantification in human brain regions: comparison between Alzheimer’s and nondemented patients.

Weill-Engerer S, David JP, Sazdovitch V, Liere P, Eychenne B, Pianos A, Schumacher M, Delacourte A, Baulieu EE, Akwa Y.Neurosteroid quantification in human brain regions: comparison between Alzheimer’s and nondemented patients.J Clin Endocrinol Metab. 2002 Nov;87(11):5138-43

Abstract: “…To investigate the physiopathological significance of neurosteroids in Alzheimer’s disease (AD), we compared the concentrations of pregnenolone, pregnenolone sulfate (PREGS), dehydroepiandrosterone, dehydroepiandrosterone sulfate (DHEAS), progesterone, and allopregnanolone…in individual brain regions of AD patients and aged nondemented controls, including hippocampus, amygdala, frontal cortex, striatum, hypothalamus, and cerebellum.

A general trend toward decreased levels of all steroids was observed in all AD patients’ brain regions compared with controls: PREGS and DHEAS were significantly lower in the striatum and cerebellum, and DHEAS was also significantly reduced in the hypothalamus. A significant negative correlation was found between the levels of cortical beta-amyloid peptides and those of PREGS in the striatum and cerebellum and between the levels of phosphorylated tau proteins and DHEAS in the hypothalamus. This study provides reference values for steroid concentrations determined by gas chromatography-mass spectrometry in various regions of the aged human brain. High levels of key proteins implicated in the formation of plaques and neurofibrillary tangles were correlated with decreased brain levels of PREGS and DHEAS, suggesting a possible neuroprotective role of these neurosteroids in AD.”

Pregnenolone main page

Hot Flashes and Sleep

Researchers writing in the medical journal Menopause say that ambient temperature and REM sleep patterns effect sleep in postmenopausal women.

Freedman RR, Roehrs TA.Effects of REM sleep and ambient temperature on hot flash-induced sleep disturbance. Menopause. 2006 Jul-Aug;13(4):576-83.

From the study abstract:
OBJECTIVE:: To determine whether hot flashes produce sleep disturbance in postmenopausal women.

DESIGN:: This study was performed in a university medical center laboratory with 18 postmenopausal women with hot flashes, six with no hot flashes, and 12 cycling women, all healthy and medication free. Polysomnography, skin and rectal temperatures, and skin conductance to detect hot flashes were recorded for four nights.

Nights 2, 3, and 4 were run at 30 degrees C (86 degrees F), 23 degrees C (about 73.5 degrees F), and 18 degrees C (about 64.5 degrees F) in randomized order.

RESULTS:: During the first half of the night, the women with hot flashes had significantly more arousals and awakenings than the other two groups and the 18 degrees C ambient temperature (about 64.5 degrees F) significantly reduced the number of hot flashes.

These effects did not occur in the second half of the night. In the first half of the night, most hot flashes preceded arousals and awakenings. In the second half, this pattern was reversed.

CONCLUSIONS: In the second half of the night, rapid eye movement sleep suppresses hot flashes and associated arousals and awakenings. This may explain previous discrepancies between self-reported and laboratory-reported data in postmenopausal women with hot flashes.