I'm 61 and I noticed that problem a year ago. My doctor did check everything on me and everything is good with my health. What happen is that the body develops tolerance reacting to alcohol, therefore, alcohol is no longer so much a diuretic anymore. Also as part of the tolerance the body learns to retain water to fight dehydration. What I found helpful for these effects is to cut as much as possible on salt, sugar and carbohydrates when drinking. And the best don't drink more than 4 beers, or not more than 35oz of liquid with hard liquor. And by no means drink two days in a row.