If one drink/wk is noticeably affecting you then you're either a professional athlete who's got world class people monitoring their performance or you need to see a doctor.

Edit: Assuming the standard definition of drink that's roughly equivalent to one light beer or one shot

It’s not like I suddenly break down or something. There are a few factors in my sport. BJJ is mostly cardio so I sweat a lot. I train at or close to my limits most of the time. Recovery isn’t as easy at 41. Alcohol depletes just enough from my body and impedes recovery just enough that the next day, I won’t be 100%, and I’ll feel it. Even one drink in the evening is massively disruptive to sleep processes like REM sleep. It depletes key nutrients from muscles, etc. so maybe I’m just a little slower.

Then there is the cramping. Replenishing electrolytes when you leak as much of them as I do is hard. There is a really good chance I will get a moderate to severe cramp if I drank the night before. I think you are underestimating how significant a drink can be to someone training hard. Especially someone older, such as myself. You have to make a very large number of assumptions to arrive at your conclusion that is obviously incorrect for many athletes hobbyist or otherwise. Some guys can pull it off, and there are a few in my gym who can drink hard, come in hungover and survive a hard training session. That isn’t me or most people I know (anecdotally).

OT: Training close to your limits all the time is counter productive. Read up on block periodization for how you get more from your training.

Good point. I don’t periodize my BJJ training, but when I am tired and sore I go light. I like an undulating periodization model for both cardio and strength work. Rest and knowing what the precursors to overtraining are like are huge. My “limit” training is what I can maintain year round. Base training as it were with smart full breaks here and there. I have read way too many books on strength training and running, used to run ultras and lift a lot before embracing martial arts. Undulating periodization basically works out to a few different training intensities and modalities that are cycled through carefully to promote stimulus and avoid overtraining. It’s similar to block periodization in concept to block periodization but the blocks are more flexible and at my age much shorter before I have hit the max benefit of a block and moved on to the next one. The cool thing about undulating periodization is you pick up where you left off in a block.

You might be overtraining. When I trained in BJJ and also tried to weight train as well as cardio I felt the difference between drinking or not. But that largely went away when I stopped trying to do so much. Other health markers improved as well (sleep, RHR, etc.)

Just a thought if you're noticing a single drink that much.

I have been doing it for a number of years now. My limit is what I can do while maintaining great deep sleep, etc. I can occasionally push harder, but then sleep and overtraining creeps in. So, I am staying somewhere comfortably under that overtraining threshold. Even minimal alcohol consumption starts really messing things up :)

Why? I do a minimal amount of exercise and I can feel the difference if I had one drink the night before. Forget exercise, it’s obvious I had a drink the night before from how I feel as soon as I wake up, just from the degree to which alcohol negatively effects quality of sleep.

I feel hung over whether I drink one beer or six, it doesn't really change. I don't even feel any 'buzz' if I drink one beer, mixed drink or glass of wine, but will just feel bad for the next 12-hours.

I am 42, so close in age to the OP, and I, too, notice that recovery from workouts is easier when I have zero alcohol in a week then, well, not one, but three drinks a week. And better sleep might be the explanation.

That substance is not exactly harmless.

You get used to it (playing a sport hungover, even). If you’re not a competitive athlete on a high level (it’s just a hobby), you’re missing out by not drinking because of your sport. If you enjoy drinking, that is.

Plenty of people compete as a hobby. You might also say if they were drinking, they'd be missing out on performance. If they enjoy performing better, that is.