|The healthy lifestyle rhythm: "Sleep, eat, train, live, sleep,..." × 365 days/year|
This means that it won't touch on the 19% increase in copulatory efficiency and the other "significantly facilitated" aspects of sexual activity (mounting latency -80%, ejaculatory latency -63%, etc.) scientists from the University of British Columbia observed in melatonin treated (4 mg/L of drinking water) Long-Evans rats (Brotto. 2002).
Rather than that we are going to focus on the non X-rated semantics of "to sleep", its health effects and the role of melatonin in sleep, health and disease. So, let's see what we've got in stock for you:
- Profound effects of sleep restriction on the human plasma metabolome (Bell. 2014) -- In spite of the the fact that it is well established that short sleep durations and/or poor sleep quality induce changes in our energy and substrate metabolism (Penev. 2012) that increase your risk of developing diabesity (Cappuccio. 2010), we know very little about the biochemical signatures involved in the pathogenesis of type 2 diabetes[5–9]. How bad is bad sleep? That's a pretty good question and if we put faith in the latest meta-analyses by researchers from the University of Warwick and the University of Naples Medical School, it's pretty bad - at least that's what I would call something that is associated with increases in ...Bell et al. did thus decide to use a metabolomic profiling approach to assess the impact of recurrent sleep restriction on human intermediary metabolism to identify biochemical signatures that may reflect the effects of sleep curtailment on metabolic risk. To this ends, each study participant completed two 8-night inpatient sessions with restricted (5.5-h time-in-bed) vs. adequate (8.5-h time-in-bed) sleep opportunity while daily food intake and physical activity were carefully controlled.
- diabetes - 28% increased risk with sleep duration ≤5–6 h/night, 48% increased risk with difficulty in initiating sleep, and 84% increased risk with difficulty maintaining sleep (Cappuccio. 2010),
- cardiovascular disease - 48% increased risk of developing or dying of CHD with short sleep durations (≤5–6 h/night), and 38% increased risk of coronary heart disease , 65% increased risk of stroke, and 41% increased risk of for any form of CVD with long duration (>8h/night) sleep (Cappuccio. 2011),
- all-cause mortality - 12% higher all-cause mortality risk for short duration of sleep (≤5–6 h/night), +30% all-cause mortality risk with long-duration sleep (>8h/night) (Cappuccio. 2012)
The subsequent combination analysis of 362 biochemicals in fasting plasma samples that were collected from study participants the morning after each 8-night sleep treatment revealed that..
- the relative concentrations of 12 amino acids and related metabolites were increased when sleep was curtailed
- sleep restriction also induced elevations in several fatty acid, bile acid, steroid hormone, and tricarboxylic acid cycle intermediates, and surprisingly
- the circulating levels of glucose, some monosaccharides, gluconate, andfive-carbon sugar alcohols tended to decline when sleep was reduced.
Incidentally, the same is true for the answer to the question whether similar changes would have been observed if the hitherto healthy, lean subjects didn't have a parenteral history of type 2 diabetes. The Bell study must therefore be seen as a first in a series of studies that could broaden our insights into the role of abnormal sleeping patterns in the etiology of type II diabetes and other metabolic disease.
- Food ↻ sleep interactions and their potential role in the etiology of diabesity (Chaput. 2013) -- The insights we may gain from the previously discussed study by Bell et al. may give some indication of whether or not the increase in energy intake that's so characteristic for sleep deprived human beings is a crucial, necessary or conditional contributer to the increased diabetes and obesity (=diabesity) risk in this population.
Figure 1: Potential mechanisms by which insufficient sleep may facilitate the ingestion of calories (Chaput. 2013)
Other examples of sleep-promoting foods include herbal products (e.g. chamomile
tea) and certain fruits (e.g. tart cherries or kiwifruits), but again, robust scientific evidence supporting this is, in many cases, nonexistent (Pehkuri. 2012). And with respect to tryptophan, which is a precursor to the neurotransmitter serotonin and the neuro-secretory hormone melatonin, have only been confirmed in studies using pharmacological doses way above the maximal amount you could get from food.
- Can exercise attenuate the metabolic effects of dim light at night? (Fonken. 2013) -- You will be aware that going to bed right after an intense HIIT session is beside the point. Your chances of falling to and gettins some restful sleep don't border zero, they are zero. Against that background it may initially sound surprising that researchers from the Department of Neuroscience at the Ohio State University have recently argued that exercise could exert at least part of its beneficial anti-obesity effects by strengthening and realigning the circadian rhythm.
To test this hypothesis Fonken et al. maintained four groups of mice in either dark (LD) or dim (dLAN) nights and provided them with either a functional or a locked running wheel or a locked wheel. As it turned out, "[m]ice exposed to dim, rather than dark, nights increased weight gain." If the mice had access to a functional running wheel, however, the dim light at night hat no effect on their body mass.
This sounds fantastic. Unfortunately, the effect was not brought about by a preventive effect exercise may have on the dim-light-induced defect of the animals circadian system. It was brought about by an increase in energy consumption by the means of which the rodents compensated for the increases in daytime food intake.
- Melatonin supplements work and won't lose efficacy over time (Ferracioli-Oda. 2013) -- In view of the fact that the classics, i.e. milk and camomile tea obviously don't do much to improve your sleep quality (see previous paragraph), it's all the more important to emphasize that Eduardo Ferracioli-Oda, Ahmad Qawasmi, and Michael H. Bloch's meta-regression analysis that examined the influence of dose and duration of melatonin on reported efficacy yielded results all the melatonin lovers out there will certainly appreciate.
Figure 2: Restoring reduced melatonin levels (A,B,C) to youthful levels by supplementation (1-3) counters the build-up of ameloid plaque (➲Alzheimer's; cf. Lahiri. 2004).
- reduces sleep latency by t = 7.06 min
- increases total sleep time by t = 8.25 min
- promotes overall sleep quality (+22%)
The often-heard hypothesis that you could build up a tolerance over time is thus not supported by scientific evidence. And dependence, as it is common with benzodiazepines is not an issue (Srinivasan. 2011)
- Bell, Lauren N., et al. "Effects of sleep restriction on the human plasma metabolome." Physiology & behavior 122 (2013): 25-31.
- Brotto, Lori A., and Boris B. Gorzalka. "Melatonin enhances sexual behavior in the male rat." Physiology & behavior 68.4 (2000): 483-486.
- Bubenik, G. A., and S. J. Konturek. "Melatonin and aging: prospects for human treatment." Journal of Physiology and Pharmacology 62.1 (2011): 13.
- Cappuccio, Francesco P., et al. "Quantity and Quality of Sleep and Incidence of Type 2 Diabetes A systematic review and meta-analysis." Diabetes Care 33.2 (2010): 414-420.
- Cappuccio, Francesco P., et al. "Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies." Sleep 33.5 (2010): 585.
- Cappuccio, Francesco P., et al. "Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies." European Heart Journal 32.12 (2011): 1484-1492.
- Fonken, Laura K., et al. "Exercise attenuates the metabolic effects of dim light at night." Physiology & behavior 124 (2014): 33-36.
- Lahiri, Debomoy K., et al. "Dietary supplementation with melatonin reduces levels of amyloid beta‐peptides in the murine cerebral cortex." Journal of pineal research 36.4 (2004): 224-231.
- Lin, Li, et al. "Melatonin in Alzheimer’s Disease." International journal of molecular sciences 14.7 (2013): 14575-14593.
- Peuhkuri, Katri, Nora Sihvola, and Riitta Korpela. "Diet promotes sleep duration and quality." Nutrition Research 32.5 (2012): 309-319.
- Penev, P. D. "Update on energy homeostasis and insufficient sleep." Journal of Clinical Endocrinology & Metabolism 97.6 (2012): 1792-1801.
- Srinivasan, Venkatramanujan, et al. "Melatonin agonists in primary insomnia and depression-associated insomnia: Are they superior to sedative-hypnotics?." Progress in Neuro-Psychopharmacology and Biological Psychiatry 35.4 (2011): 913-923.
- Valtonen, M., et al. "Effect of melatonin-rich night-time milk on sleep and activity in elderly institutionalized subjects." Nordic Journal of Psychiatry 59.3 (2005): 217-221.
- Yamamura, S., et al. "The effect of Lactobacillus helveticus fermented milk on sleep and health perception in elderly subjects." European journal of clinical nutrition 63.1 (2007): 100-105.