Category: performance

>Sleep and teenagers


Sleep (or lack of…) is an interesting topic. Quality of sleep has been shown to negatively affect human performance for various reasons. Furthermore, there have been numerous reports suggesting a link between lack of sleep and depression.

The relationship between short sleep duration and depression has been suggested to be bidirectional,1 with chronic partial sleep deprivation being a potential risk factor for depression. Cross-sectional studies have found relationships between inadequate sleep and depression in adolescents,2,3 and a longitudinal study has shown that getting less sleep over time increased the symptoms of depression among middle school students.4 Short sleep duration has also been shown to be associated with suicidal ideation5 and suicidal behavior6 in adolescents and adults7 in cross-sectional studies.

A recent quasi-experimental study conducted by Gangwish et al. (2010) has looked at the relationships between parental set bedtimes, sleep duration, and depression in adolescents to explore the potentially bidirectional relationship between short sleep duration and depression.

For this scope they analysed 15,659 US adolescents in grades 7 to 12. The results showed that adolescents with parental set bedtimes of midnight or later were 24% more likely to suffer from depression (OR = 1.24, 95% CI 1.04-1.49) and 20% more likely to have suicidal ideation (1.20, 1.01-1.41) than adolescents with parental set bedtimes of 10:00 PM or earlier, after controlling for covariates. Consistent with sleep duration and perception of getting enough sleep acting as mediators, the inclusion of these variables in the multivariate models appreciably attenuated the associations for depression (1.07, 0.88-1.30) and suicidal ideation (1.09, 0.92-1.29).

From Table 3
Odds ratios (95% CI) for depression

Model 1a Model 2b Model 3c Model 4d
Parental set bedtime on weekday nights
10:00 PM or earlier 1.00 1.00 1.00 1.00
By 11:00 PM 1.15 (0.94-1.40) 1.13 (0.90-1.42) 1.10 (0.87-1.39) 0.97 (0.76-1.24)
By or after midnight 1.42 (1.21-1.67) 1.28 (1.07-1.52) 1.24 (1.04-1.49) 1.07 (0.88-1.30)
Self-perception of how much parents care
1 – Not at all 6.82 (3.11-14.98) 5.88 (2.79-12.40)
2 – Very little 8.32 (4.58-15.12) 6.73 (3.49-12.98)
3 – Somewhat 5.50 (3.72-8.13) 4.93 (3.32-7.30)
4 – Quite a bit 2.43 (1.89-3.13) 2.16 (1.69-2.76)
5 – Very much 1.00 1.00
Adolescent-reported sleep duration
≤ 5 h 1.71 (1.22-2.39)
6 h 1.29 (0.97-1.70)
7 h 1.19 (0.96-1.48)
8 h 1.00
9 h 1.17 (0.88-1.56)
≥ 10 h 1.34 (0.95-1.89)
Enough Sleep 0.35 (0.28-0.43)
aModel 1 – Unadjusted.
bModel 2 – Adjusted for age, sex, race/ethnicity, parent’s marital status, and family receipt of public assistance.
cModel 3 – Adjusted for variables in Model 2 plus self perception of how much parents care.
dModel 4 – Adjusted for variables in Model 3 plus adolescent reported sleep duration and perception of getting enough sleep.

The results from this study provide new evidence to support the notion that short sleep duration could play a role in the etiology of depression. Earlier bedtimes could therefore be protective against adolescent depression and suicidal ideation by lengthening sleep duration.

Young athletes have to cope nowadays with various stresses, not only performance related. Studying, maintaining social contacts, training, family and peer pressure are all parts of young athlete’s  lives. Sleep is a simple thing that can make sure they recover properly and can cope with everything they have to deal with.

So, are we making sure they get good quality and good amounts of sleep?

Do we advice them on appropriate bed time?

Do we make sure they don’t spend the night playing videogames or chatting on social networks?

Do we create the right sleeping environment and routines?

Do we know if they are sleeping well?

How about a checklist?

Read Atul Gawande’s book about checklists, The Checklist Manifesto. Not only is the book loaded with fascinating stories, but it honestly changed the way I think about the world. The book’s main point is simple: no matter how expert you may be, well-designed check lists can improve outcomes. So, let’s make sure our young athletes tick all the boxes when it comes to sleep.

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.

Analyzing your health by phone?

Just read an interesting article on a new voice recognition software able to detect how you are feeling. The emotional decoding software has been developed in Israel and sounds interesting.

The technology, developed by eXaudios Technologies, is already being used to transform the world of tele sales (sadly…), and future applications could include diagnosis of conditions such as autism and Parkinson’s, as well as their severity.

I believe there is mileage in looking at applications of voice and face recognition to understand fatigue/staleness and stress in athletic populations as well as in coaching staff. Previous work by Greeley et al. has suggested the possibility of detecting fatigue with voice recognition. Work by Ruiz et al. (1990) already suggested the possibility of voice analysis to detect psychological or physical state of an individual.

All I can say is that this technology is part of a speculative grant application to look at a multidisciplinary approach to understand and quantify stress and fatigue in various populations. Let’s hope it gets funded so you may see the results in few years time!

In the meantime, the video from Exaudios technologies is here.