See the bottom of the page for evidence pyramid explanation.
1. Nedeltcheva et al. (2010). Insufficient sleep undermines dietary efforts to reduce adiposity
- All 10 overweight adults all ate 90% of their Resting Metabolic Rate in calories per day, which was about 1300 kcal.
- Every single participant underwent 2 conditions for 2 weeks: sleeping 7.5h per night and sleeping 5.25h per night.
- In both sleeping conditions they lost 2.9-3 kg. However, 1.5 kg of this was muscle in the 7.5h sleep group, versus a whopping 2.4 kg in the 5.25h sleep group.
- Limitation: they did not weight train, which may have saved a lot of muscle mass.
2. Scullin et al. (2018). The Effects of Bedtime Writing on Difficulty Falling Asleep: A Polysomnographic Study Comparing To-Do Lists and Completed Activity Lists
- First study in this area to use polysomnography (brainwave recording) instead of self reported sleeping hours.
- Active control group that journalled 5 min. about what they had accomplished the past day
- The alternative hypothesis was that writing a to-do list for the next day will “off-load” those thoughts from consciousness (i.e., Pennebaker-like effects), and thereby make you go to sleep faster.
- The alternative hypothesis group that spent 5 min. writing a to-do list slept up to 40 min sooner than the other group, and the more detailed their to-do list, the sooner they fell asleep.
- The key seems that participants wrote down their to-do list rather than mentally ruminating about their unfinished tasks.
3. Viola et al. (2008) Blue-enriched white light in the workplace improves self-reported alertness, performance and sleep quality
Strength of evidence explanation:
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