[SpaceInvader]

I'm an avid runner (50-70km/week) and I've been running for 5 years. I run long distances on trail.

Seems that although it increases performance and stamina for me it also brings my heart rate up, which is not desirable in most cases since I'm training ~80% of the time in zone 2 (aerobic). At given pace I can have few bits higher HR when caffeinated (between 5 and 10 bpm) which means that I need go go slower in order to stay in zone 2.

For me it's a tool that I'm using during races. Also worth noting is that caffeine works on me really well.

[nmdeadhead]

I too am a runner (~100 mi/week when not tapering or recovering) and "normally" I limit my caffeine to a double espresso at 5:15am. I take that one to synchronize my sleeping and bowels. However, it's a little more complicated than that because I divide the year into three different major training blocks and what I do varies both by which major block I'm in as well as what I'm doing within that block.

As such, there are trainings where I use extra caffeine for a variety of different purposes, e.g. to get maximum speed to train my body to go faster, or for the mild analgesic effect to counter some discomfort from long distances. Depending on how much extra I take and when, I may have to take the attendant tiredness into account when planning the following day's activities, both physical (more training) and mental (programming).

I believe I benefit from my use of caffeine, but it's tricky. I log all the caffeine I take as well as all the calories, analgesics and alcohol in a text file (which I keep in a public repository in GitHub). I can then look back and try to figure out what's worked well in the past so I can do more of it as well as what has held me back.

[sonthonax]

Heart rate isn’t a good metric to be iron clad to. It’s far to variable as your stroke volume changes in response to: stimulants, sleep, stress, external heat, blood pressure, body temperature, and time spent running.

For all of the fitness tracking that exists, perceived exertion and relative pace to your max is better.

[pengaru]

I've noticed that the psychological effects of caffeine disrupt my ability to pace myself, but I like to use heavy doses when I'm using it at all. I just become so eager/impatient on the drug, it's all go-go-go and my discipline is out the window.

It's great for getting shit done in a sprinty bulldozer, potential wake of destruction kind of mode. But I can't imagine it working well for me in a distance running context where managing my cadence and cardio/breathing is key.

[intense122]

Agree. If I want some energy boost I drink matcha, sencha.. green teas. Looks like it kicks off faster than coffee for me, but depends, for example matcha seems a bit harder for gut when drinking before workout. Some of them could be helpful for fat burning also combined with zone 2 but I am not sure, wasn't reading about this.