Caffeine tends to 'wake me up'. I'm a restaurant manager and I tend to have an americano on days that I open, at about 5am and it kinda kick starts the day.

There are negatives with it though.

I DO have a very sensitive stomach and caffeine really does exacerbate all issues that I have. If I overdo it routinely, I'll get to where I am in almost constant mild stomach pain, with occasional sharp 'twinges'

Also, if I am overly tired, I don't really notice the 'high' as much, but I get a really bad 'crash'. In effect it will make me so sleepy I can go to sleep while standing on my feet.

The other bad side is that when I've had a week or so of those super early shifts, my body will get accustomed to having those stronger doses of caffeine early in the day. Consequently, I'll wake up at 7/8am with the start of a headache simply because I am hours past due for my caffeine fix.

Even with all that though, I still love my americanos

Having been in the same situation (pregnancy and BF), I can chime in and say that I too quit coffee for most of my pregnancy though I did pick it up again at the last trimester. I also continued to drink coffee through 18mos of BF with no adverse effects on me or baby.

I cannot attest to having a high tolerance to caffeine. My tolerance for it has never grown. I've been drinking coffee for nearly 20yrs and have never had a need to drink more than one cup per day. Is it just me? I can only drink one cup in the morning, any more than that and I can't sleep at night. I have a sensitive stomach and do need to eat something with my coffee otherwise it brings on stomach pain. Occassionally I like to indulge in a cup in the afternoon but it has to be decaf.

Everything in moderation, moderating coffee comes very easily to me. If you think you'll have trouble staying to one cup then it's best to be careful but you don't have to eliminate it entirely.

I know a lot of people that use caffeine to help boost their work outs, unfortunately I am allergic to it so I cannot.