Aici avem o metaanaliza destul de serioasa, din care avem un capitol "The impact of caffeine consumption on subsequent sleep quality" si pun aici cateva fragmente care mi s-au parut interesante:
1. the Atahualpa Project, using data collected in an Ecuadoran village with no fast food outlets, almost no shift work, and little light or noise pollution during the evening and night hours—and almost certainly a very different cultural orientation toward caffeine—found no impact of caffeine consumption on sleep patterns when controlling for other physiological variables.39 The researchers note that the absence of caffeine impact on night sleep quality may be associated with the absence of other secondary triggers to wakefulness, such as noise or artificial light. DAR
2. Drake et al41 examined the effect of 400 mg of caffeine administered at three points prior to their participants’ usual bedtime, and found that doses even 6 h prior to bedtime significantly disturbed sleep compared to placebos.
3. Karacan et al’s classic study42 took a different approach, using a single population and varying doses of caffeine administered 30 min prior to bedtime in a balanced Latin-square design, finding the impact on TST was dose related. Caffeine shifted rapid eye movement to the early part of the night and stages 3 and 4 to the latter end of the (shortened) sleep period.
4. Landolt et al43 investigated the role of caffeine in sleep regulation, with participants administered 200 mg of caffeine in the early morning (7 am) and then monitored using electroencephalography. Caffeine levels in the saliva were observed to spike 1 h after intake, falling to less than a fifth of that level (3 µmol/L) 16 h later. Despite this reduction at sleep onset, both sleep efficiency and TST were significantly reduced in experimental conditions, relative to placebo. The presence of caffeine in the central nervous system, the authors concluded, reduces the gradual onset of drowsiness associated with extended periods of wakefulness.
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5. It is possible that people learn to regulate consumption to fit their individual patterns of response. A study of 2,202 randomly selected residents of three European nations (Iceland, Sweden, and Belgium) gathered data on sleep characteristics and the use of psychoactive substances including coffee.44 They found that caffeine consumption did not predict difficulties inducing sleep or other sleep disturbances when age, gender, smoking, and seasonal variations were controlled for.
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