It turns out that many years of excess can be bad for you. Like many people, I had developed what you may call a coffee addiction. Actually, you would absolutely call it a coffee addiction: having headaches when you don't have some coffee is a telltale sign!
As far as volume goes, we're talking about somewhere on the order of eight cups a day, or ~2/3rds of a carafe all by myself. Coffee tastes great, but in retrospect this was clearly too much of a good thing, and I had been going at close to this rate for several years at this point.
But for whatever reason, it was around last August when the effects of all that coffee started to be more severe than anything "harmless". I started to feel perpetually "off" for much of the day. I'd describe it as some kind of intermittent brain fog and/or drowsiness. It became harder and harder to focus - I could be staring at the computer screen and my eyes would "zoom out" and I'd struggle to get them back into focus for a bit.
All in all, it was fairly concerning... but I couldn't figure out what was causing it! Was it long covid? Was it cancer? Was it just getting old? Was it environmental toxins in our home or nearby area?
I ran through all these possibilities without really considering the option that it was the large amounts of a drug (caffeine) that I was pouring into my body every day. While excessive, my level of caffeine intake hadn't changed all that much over the past three years. Maybe a slight increase, but it had been high for a while. Thus my mind jumped to the more exotic and unlikely causes noted above.
But what ultimately tipped me off was that I found that whenever I went back East to see family, I tended to feel better. Not right away, but after a few days back there the aforementioned issues seemed to go away. While this didn't rule out other causes (e.g. environmental toxins), it eventually led me to the stunning realization that the issue may be the volume of caffeine I was taking in each day.
As near as I can tell from the research, your body adapts to what you put into it... to a point. In the case of coffee, it stimulates your body. However, your body knows that it needs to sleep, and so it produces more chemicals that make your body tired... which leads you to want more coffee. It is an arms race basically, with each side waging war on the other every day (and night).
Practically speaking, this leads your body to be tired and awake at strange times and (for me) feel tired even after a good night's sleep. I'd then start to feel "more normal" and awake as it got into the late evening, even though my body was still clearly tired after being up all day. It was a weird feeling.
Fast forward to today, and I have a few months of data on my coffee reduction. I felt a lot better in the week or two immediately following the reduction. I felt more energized and more focused during that time, and didn't miss the coffee much at all! Since then, my body seemed to have adapted to the new normal, and the effects became less noticeable.
That said, taking care of that in conjunction with getting my high blood pressure under control has really helped my energy levels throughout the day and how I feel overall, which I'm pretty excited about! Combining all of that with a modest increase in exercise, and I have my resting heart rate back in the high 40's (if I don't drink any alcohol that day).
Long story short: cutting my caffeine levels down has been a huge positive!
All that said, my advice to you, dear reader, is to consider cutting back on caffeine if you drink a fair bit of coffee. Or more broadly: assess your routine and call into question anything and ask "am I sure that this is helping me?" or "what could be some negative consequences of this routine?" At the end of the day, the only person who can make improvements in your life is yourself.
It's on you. Our current culture and current media would have me searching for someone else to blame: coffee companies! workforce culture! the government should regulate coffee more! No. Not even your doctor is responsible for your health. At best they are a helpful advisor. But the ultimate responsibility for your health is yours and yours alone.