Originally Posted by Excelsius
Nevertheless, I never drink any coffee.
Apart from the caffeine tablets, do you currently have any other sources of caffeine in your diet (tea, cola etc)? Personally, I drink 2-3 cups of coffee per week as well as 5-6 cups of green tea per day. This doesn't appear to have any impact on biphasic sleep (I'd imagine that polyphasic is similar in this regard), but occasionally I have more caffeine than this and that DOES affect the quality of sleep.
The amount of caffeine defintely can make a difference (at least in my case).