Even very mild dehydration can ruin your mood, cloud your thinking, and limit your body’s ability to bounce back after exercise, research shows. But a lot of guys—especially during the cooler, dryer months—don’t put much thought into proper pre- and post-workout hydration.

That’s a mistake. Even when you’re just sitting around doing nothing, your body loses about 10 ounces of water an hour due to “insensible perspiration,” shows research from the University of North Carolina. And while you may not visibly sweat much during cold-weather jogs or gym sessions, your brain and muscles will still suffer the ill effects of dehydration if you’re not rehydrating properly.

At the same time, over-hydration is a surprisingly common problem, especially for endurance athletes.

Here’s how to ensure you’re giving your body what it needs, without overdoing it.

If you’re exercising for less than an hour and your clothes aren’t accumulating much sweat, skip the sports drinks and stick to water, says Joy Dubost, PhD, a sports dietician and spokesperson for the Academy of Nutrition and Dietetics. Drinks like Gatorade and Powerade tend to be loaded with sugar and other not-so-healthy carbohydrates. That stuff’s fine if you’re really busting your butt and burning energy. But it’s not necessary for short, less-intense workouts. Weigh yourself before and after your sweat session, and drink 16 to 24 ounces of water for every pound of weight you drop, Dubost advises.

Yes, you can get those from sports drinks. But “electrolyte” is just a fancy term for minerals like sodium and potassium, which you can get from all kinds of drinks that don’t pack as much of the sweet stuff as Gatorade and its ilk. One surprising electrolyte source: Milk. “Milk is as effective or possibly more effective than commercially available sports drinks at promoting recovery from strength and endurance exercise,” Dubost says. Down a small glass post-workout to get your electrolytes, then aim to get the rest of what your body requires from plain water.

A lot of guys think they need to main-line a gallon-sized protein shake after every workout in order to maximize muscle gains. But research from California State University and elsewhere has found little evidence that post-exercise protein binges promote muscle recovery and growth. In fact, new research on protein from the University of Southern California suggests slamming too much of it could up your risk for disease and premature death. Your goal should be to consume moderate amounts of protein—think 20 to 30 grams at meal times—throughout your day, Dubost says.

Alcohol isn’t the problem. (Beer actually makes a great post-exercise drink, concludes a recent study from Spain.) But the resveratrol compounds in red wine—the same stuff that seems to fight inflammation and lower your risk for heart disease—don’t play well with the health-boosting free radicals that exercise releases into your bloodstream after a workout, finds a study from Denmark. For that reason, the Danish study authors say you’re better off skipping wine after evening runs or gym visits.

Some endurance athletes—especially marathoners—are told to drink early and drink often to stay ahead of dehydration. But research from the Harvard School of Public Health shows over-hydration is more common than dehydration among long-distance runners. Drinking too much water too quickly dilutes the amount of sodium and other electrolytes in your blood, which leads to a condition called hypernatremia. That can cause dizziness, headaches, and even death, the study authors say. Again, it’s best to weigh yourself before and after a long run or workout, and judge your hydration needs based on how much weight you shed, Dubost says.