While yes you may be thinking that beer does the exact opposite, I looked into a study done by researchers at Granada University in Spain who tested 25 students by having them run on a treadmill until they were out of breath, half the group of students were given water and the other drank a spanish lager. After the activity was finished the researchers measured the hydration levels, the results were quite fascinating which resulting in the beer drinkers had a small but higher rehydration effect. The reasons being that the beer had additives sugars, salts, carbonation that enhancing the body ability to absorb water and nutrients. The carbs in the beer also helped add calories deficits that the body was lacking.
When your body is dehydrated having a beer wont make it any less dehydrated so it’s fine to enjoy a beer after a nice long run or adventurous hike with your friends. It’s funny that this study was mentioned because while I’m at work I notice people who have just come from the gym and or been working out tremendously. Having a refreshing beer will not cause any harm. It is of course important to hydrate by drinking plenty of water too just keeping things in moderation.