learning, memory, sleep

>Sleep is good for you

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Sunday is one of my favourite days as I tend to have time to do some reading. I like to read everything, but today i particularly enjoyed something recently published on sleep using an interesting animal model.

The benefits of sleep seem obvious. However, scientists have long debated precisely how it improves brain performance at the cellular level. One theory argues that sleep reduces the unimportant connections between neurons, preventing brain overload. Another theory maintains that sleep consolidates memories from the previous day.

I have previously discussed in this blog the importance of sleep for athletes with particular reference to the possibility of videogames altering the normal sleep-wake cycle.

Recent work published on Neuron shows how the circadian clock and sleep affect the scope of neuron-to-neuron connections in a particular region of the brain. The authors also identified a gene that appears to regulate the number of these connections.

The study was conduced studying the larvae of a common see-through aquarium pet, the zebrafish. Like humans, zebrafish are active during the day and sleep at night.

The researchers, led by Lior Appelbaum and Philippe Mourrain of Stanford University, tagged the larvae neurons with a dye (Synaptophysin,  pre-synaptic marker) so that active neuron connections, or synapses, appeared green, whereas inactive ones appeared black.

High-quality image (930K) - Opens new window

After following the fluctuations of these synapses over the course of a day, the team found that the zebrafish did indeed have lower overall synapse activity during sleep.

The scientist are pretty much of the impression that sleep is an active process that reduces the activity in the brain. This reduction in brain activity allows the brain to recover from past experiences.

Without the synapse reduction that happens during sleep the brain would not have the ability to continually take in and store new information. So the importance of sleep i an athletic population is not relevant only for physical recovery, but possibly to facilitate learning and memory all activities incredibly important in sports where tactical aspects are crucial.

More studies are needed but this particular study provides the first insights on NPTX2, a protein implicated in AMPA receptor clustering which modulates circadian synaptic changes. Overexpression of NPTX2b in hypocretin/orexin (HCRT) neurons induces melatonin resistance, so for sure there is a need for more studies in this field to understand the links between sleep and brain function.

monitoring, nutrition, performance, Sports Science, supplements

New recommendations for dietary intake of Vitamin D and Calcium

Most Americans and Canadians up to age 70 need no more than 600 international units (IUs) of vitamin D per day to maintain health, and those 71 and older may need as much as 800 IUs, says a new report from the Institute of Medicine. The amount of calcium needed ranges, based on age, from 700 to 1,300 milligrams per day, according to the report, which updates the nutritional reference values known as Dietary Reference Intakes (DRIs) for these interrelated nutrients.

The report’s recommendations take into account nearly 1,000 published studies. A large amount of evidence, which formed the basis of the new intake values, confirms the roles of calcium and vitamin D in promoting skeletal growth and maintenance and the amounts needed to avoid poor bone health. The current evidence in fact seems to suggest the need for increasing Vitamin D levels not only in the elderly, but also in athletic populations. In fact, young athletes and dancers have been recently identified to present vitamin D insufficiency, despite the fact they live in a sunny country, suggesting that screening and increase Vitamin D intake is necessary to avoid health problems.

The committee that wrote the report also reviewed hundreds of studies and reports on other possible health effects of vitamin D. While these studies point to possibilities that suggest potential benefits of Vitamin D supplementation, they have yielded conflicting and mixed results. Rigorous trials that yield consistent results are vital for reaching conclusions, as past experiences have shown. Vitamin E, for example, was believed to protect against heart disease before further studies disproved it.

Adequate Vitamin D levels seem to be important in athletes (in particular female athletes) as a serum 25(OH)D concentration of >or=32 and preferably >or=40 ng.mL(-1) can reduce the risk for conditions such as stress fracture, total body inflammation, infectious illness, and impaired muscle function.

A part from supplementation, outdoor training time (during peak sunlight) is important and can influence Vitamin D levels.

Something else to think about, in particular in athletes training and competing indoor and in athletes leaving in “dark” countries.

Sports Science

2010 is coming to an end: Thank you!

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This blog started for fun as a way to write about various aspects of sports science and possibly to provide freely accessible information for coaches and sports scientists around the World in a simple format and possibly using multimedia.

I personally think that this is something that scientists in academia should also do in order to reach a wider audience and also allow practitioners which cannot access scientific journals to read about their work. This experiment has been so far rewarding.

This year the blog received 18,128 visits from 130 countries. More than double the amount of the visits received last year!

Thank you for visiting this blog and thank you for the time you take to ready what I write. I will do my best to continue in 2011 and hopefully provide some useful content!

In the meantime, I wish you all a great 2011!