The figures below show the influence of coffee (grabbed in mornings and/or after 11 AM) on deep and REM sleep.
On the figures, the left bar (0) represents the average time spent without coffee grabbed, the right one (1) with, and #data on the top of the bars gives the number of nights that have been collected.
It seems that coffee negatively influences deep sleep (slightly) and REM sleep (more significantly).
However, not enough data has been collected on days without coffee consumption and this parameter has to be correlated others.
Fig. 1: Influence of coffee grabbed in the morning on deep sleep.
Fig. 2: Influence of coffee grabbed after 11 AM on deep sleep.
Fig. 3: Influence of coffee grabbed in the morning on REM sleep.
Fig. 4: Influence of coffee grabbed after 11 AM on REM sleep.
Time Frame of the experiment
30 Sept. 2012 - 6 Apr. 2013