title_body: How can I maximize the time the "high" lasts?
upvoted_answer: Without considering the amount or potency of the coffee as well as setting personal metabolism aside, you could adjust your coffee schedule according to your natural circadian rhythm, a methodology neuroscientist Steve Miller refers to as chronopharmacology.  Essentially, you use the caffeine as a propellant to your natural &quot;up&quot; rhythm. Gabrielle Taylor's article does a fine job of explaining this:
  
  When you drink coffee during the time when your body is already releasing cortisol, it won't have as strong an effect. Ideally, you want to get your caffeine during the lulls between cortisol spikes—otherwise, you start to develop a tolerance and have to drink more to get the same effect.
  Assuming you're on a regular sleep schedule, your cortisol levels naturally spike about an hour after you wake up. If you get up at 7 am, your body is naturally most awake between 8 and 9 in the morning, noon to 1 pm, and again around 5:30-6:30 pm.
  So, based on a wake time of 7 am, the best times to drink your caffeine vehicle of choice are 9:30-11:30 am and 1:30-5:00 pm. Obviously you can adjust the schedule according to your own wake time if it's earlier or later.