It takes 2 hands to clap. Previously, in my first coffee simulator,  https://janicegoh.shinyapps.io/CoffeeSimulator/ we used a simple threshold to determine caffeine efficacy and toxicity. However, this efficacy alone does not tell us exactly how alert we will be with a coffee dose. It merely provides us with a binary yes/no about coffee efficacy. For a more accurate picture, we thus need a PK-PD model instead, where we can quantify the effectiveness of caffeine on alertness in relation to its PK.

Unlike PK whose output is relatively straightforward in terms of measuring blood levels as the output, PD readouts are highly dependent on the endpoint you are looking for. In this case, we are all interested in increasing our productivity on Linkedin, so I had to look for a model that described alertness levels with caffeine.

After scouring the literature, I finally found a caffeine PK-PD model that describes various mental states of alertness by RN Burns et al. (10.4236/pp.2014.54054). This was done by getting participants to rate their level of alertness on a visual analog scale to rate their energy levels from 0 – 100, where 0 would be a category of totally exhausted, and 100 a category of very energetic.

This model helps us to understand not only how much caffeine we get in a standard cup of coffee, but also what the average person experiences upon consuming a cup of coffee. Hope you enjoy playing with the new coffee simulator 2!

Link to coffee simulator 2:  https://janicegoh.shinyapps.io/CoffeeSimulatorWithFeelings/