Sleep deprivation

A small clinical trial involving 49 older adults (average age 66) found that the group who were given a standardized mindfulness meditation program had greater improvement in sleep score than the group given a sleep hygiene education program. They also showed greater improvement on secondary measures of insomnia symptoms, depression symptoms, fatigue interference and fatigue severity. However, differences between the groups were not seen for anxiety, stress or inflammatory signaling, the last of which declined in both groups.

http://www.eurekalert.org/pub_releases/2015-02/tjnj-mma021215.php

Black DS, O’Reilly GA, Olmstead R, Breen EC, Irwin MR. Mindfulness Meditation and Improvement in Sleep Quality and Daytime Impairment Among Older Adults With Sleep Disturbances: A Randomized Clinical Trial. JAMA Intern Med. 2015;175(4):494-501. doi:10.1001/jamainternmed.2014.8081.

A small study involving 15 adults with moderate-to-severe obstructive sleep apnea and 19 controls with mild or no sleep apnea has found that predicted peak oxygen uptake (VO2), a measure of aerobic physical fitness, was significantly lower in those people with moderate to severe obstructive sleep apnea. Moreover, the number of times a person stopped breathing, for 10-seconds or more, per hour of sleep, predicted 16% of the variability observed in the group's peak VO2.

People who suffer from apnea are more likely to be obese and thus would be expected to be less fit as well, but even compared to people with similar BMI, the apnea patients had a reduced aerobic fitness. It's suggested that the sleep apnea itself causes structural changes in muscle that contributes to exercise problems.

VO2 max measurements may be an early marker for those who are at higher risk of stroke and heart attack

http://www.eurekalert.org/pub_releases/2014-12/aaos-sls120114.php

http://www.eurekalert.org/pub_releases/2014-11/uoc--sal112414.php

Beitler JR, Awad KM, Bakker JP, Edwards BA, DeYoung P, Djonlagic I, Forman DE, Quan SF, Malhotra A. Obstructive sleep apnea is associated with impaired exercise capacity: a cross-sectional study. J Clin Sleep Med 2014;10(11):1199-1204.

A study involving 302 older women (mean age 82) has found that those with moderate to severe sleep apnea were at twice the risk of having problems in performing basic functions associated with independent living.

http://www.eurekalert.org/pub_releases/2014-11/jhub-oww111214.php

Spira, A. P., Stone, K. L., Rebok, G. W., Punjabi, N. M., Redline, S., Ancoli-Israel, S., & Yaffe, K. (2014). Sleep-Disordered Breathing and Functional Decline in Older Women. Journal of the American Geriatrics Society, 62(11), 2040–2046. http://doi.org/10.1111/jgs.13108

A study involving 49 office workers, of whom 27 worked in windowless workplaces and 22 in workplaces with windows, has found that those exposed to natural light slept better, and were also more active.

Employees with windows in the workplace received 173% more white light exposure during work hours and slept an average of 46 minutes more each night.

Workers without windows had lower scores on quality of life measures related to physical problems and vitality, as well as poorer outcomes on measures of overall sleep quality and sleep disturbances.

http://www.futurity.org/windows-workers-sleep-health-745022/

Boubekri M, Cheung IN, Reid KJ, Wang CH, Zee PC. Impact of windows and daylight exposure on overall health and sleep quality of office workers: a case-control pilot study. J Clin Sleep Med 2014;10(6):603-611.

A very small study, involving eight healthy young men and women, has found that insulin sensitivity gets worse the longer you're awake during the night.

During the study, one group had just five hours of available sleep time each night for five nights before five nights with nine hours of available sleep time. The other group did the opposite, starting with nine hours of available sleep time, followed by five hours per night. Participants were allowed to eat whatever they wanted during the short-night testing period.

The simulated five-day workweek of five hours of sleep per night resulted in a 20% reduced oral and intravenous insulin sensitivity, and it took three consecutive nights of nine hours of available sleep time to restore oral insulin sensitivity to previous levels.

It's worth emphasizing that these were all young and very healthy people.

http://www.eurekalert.org/pub_releases/2015-11/uoca-los_1110415.php

Eckel, R. H., Depner, C. M., Perreault, L., Markwald, R. R., Smith, M. R., McHill, A. W., … Wright, K. P. (2015). Morning Circadian Misalignment during Short Sleep Duration Impacts Insulin Sensitivity. Current Biology, 25(22), 3004–3010. http://doi.org/10.1016/j.cub.2015.10.011

Sleep apnea is common among overweight and obese individuals, and many people with prediabetes have untreated sleep apnea, although few of them are aware of it.

A study involving 39 middle-aged, overweight or obese volunteers with prediabetes and sleep apnea has found that those who received two weeks of CPAP treatment improved their blood sugar control and the ability of insulin to regulate their blood sugar, and also had lower blood pressure and lower levels of the stress hormone norepinephrine.

Two-thirds of the volunteers received continuous positive airway pressure (CPAP) for eight hours during the night; the other 13 received a placebo to be taken before bedtime. They were told the study would compare the two treatments. All participants slept in the sleep laboratory and were closely monitored.

http://www.eurekalert.org/pub_releases/2015-04/uocm-esa042715.php

Sushmita Pamidi, Kristen Wroblewski, Magdalena Stepien, Khalid Sharif-Sidi, Jennifer Kilkus, Harry Whitmore, and Esra Tasali "Eight Hours of Nightly Continuous Positive Airway Pressure Treatment of Obstructive Sleep Apnea Improves Glucose Metabolism in Patients with Prediabetes. A Randomized Controlled Trial", American Journal of Respiratory and Critical Care Medicine, Vol. 192, No. 1 (2015), pp. 96-105. doi: 10.1164/rccm.201408-1564OC

A review of 12 studies involving more than 225,000 people, of whom almost 15,000 had diabetes, has found that shift work carries a 9% higher risk of type 2 diabetes, especially in men and those with rotating shift patterns. Men, in fact, had a 37% greater risk of developing diabetes if they did shift work, while those who did rotating shifts had a 42% higher risk than those who worked a fixed shift pattern.

http://www.theguardian.com/society/2014/jul/25/shift-workers-higher-risk-type-2-diabetes-study

Gan, Y., Yang, C., Tong, X., Sun, H., Cong, Y., Yin, X., … Lu, Z. (2015). Shift work and diabetes mellitus: a meta-analysis of observational studies. Occupational and Environmental Medicine, 72(1), 72–78. http://doi.org/10.1136/oemed-2014-102150

A Greek study involving 386 middle aged patients (average age 61) with arterial hypertension has found that those who had a midday nap had lower systolic BP than those who didn't. Their average systolic BP readings were 4% lower when they were awake (5 mmHg) and 6% lower while they slept at night (7 mmHg) than non-midday sleepers .

Moreover, midday sleepers had pulse wave velocity levels that were 11% lower and left atrium diameter was 5% smaller — suggesting there is less damage in the arteries and heart. Additionally, midday sleepers had greater dips in blood pressure during the night (which is a good thing), and they took fewer antihypertensive medications.

Longer naps were better than shorter.

The research was presented at the 2015 ESC Congress.

http://www.eurekalert.org/pub_releases/2015-08/esoc-mna082815.php