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I'm stunned that the paper doesn't mention this.

I think the paper is simply "caffeine before bedtime is bad for sleep".

Especially when you consider that similar studies conclude that caffeine has an overall positive effect on brain function when consumed at 200mg per sitting and 400mg per day.

https://pubmed.ncbi.nlm.nih.gov/26677204/

100mg being equivalent to one cup of coffee or two cups of tea. I personally prefer tea as it is milder and the lower caffeine content means I can drink it all day.

Tea also has l-theanine, and that removes the jitters from consuming a lot of caffeine.

All caffeine consumption stopped at noon. It’s literally in the paper.

That's the time that the subjects stopped consuming caffeine as part of their usual diet, not the time that the pill (either 200 mg caffeine or a placebo) was administered. The subjects were required to maintain their usual caffeine intake (to prevent withdrawal), but had to stop by noon to prevent that caffeine from interfering with the experiment.

Thanks for clarifying.

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