Water is the single most important thing to drink before a workout, and the timing matters more than most people realize. Aim for about 20 ounces roughly one to two hours before you start, then another 10 ounces about 15 minutes before. Beyond water, a few other drinks can genuinely improve your performance depending on the type of exercise, how long it lasts, and your goals.
Water: How Much and When
Starting a workout even mildly dehydrated reduces your endurance, strength output, and focus. The simplest strategy is to drink 20 ounces of water one to two hours before exercise, which gives your body time to absorb the fluid and lets you use the bathroom before you start. Then top off with another 10 ounces about 15 minutes out. This two-stage approach prevents that heavy, sloshing feeling while still ensuring your muscles and blood volume are fully primed.
A quick self-check: your urine should be pale yellow before you begin. Dark yellow means you’re behind. Completely clear means you may have overhydrated, which can dilute your electrolytes without adding benefit.
Coffee and Caffeine
Caffeine is one of the most well-studied performance boosters in sports nutrition, and it works for both endurance and strength-based exercise. Doses as low as 100 to 200 milligrams (roughly one strong cup of coffee) improve endurance without the jitteriness, elevated heart rate, or GI problems that higher doses can cause. For reference, the performance-enhancing range studied in labs runs from about 1.5 to 9 milligrams per kilogram of body weight, but starting at the low end is the smartest move for most people.
Timing is straightforward. Caffeine peaks in your bloodstream about 30 to 60 minutes after you drink it, so a cup of coffee an hour before your session hits the sweet spot. Black coffee or espresso works perfectly. If you prefer a pre-workout supplement, check the label for the caffeine dose so you’re not accidentally doubling up with your morning coffee.
One thing to watch: caffeine is a mild diuretic, so make sure your water intake stays on track alongside it.
Sports Drinks and Carbohydrate Beverages
If your workout will last longer than 60 to 90 minutes, or if you’re training hard in the heat, a sports drink before and during exercise can help maintain energy and replace electrolytes lost through sweat. The key detail here is carbohydrate concentration. Drinks with 4 to 6 percent carbohydrate (about 40 to 60 grams per liter) empty from your stomach at roughly the same rate as water, meaning they hydrate you while delivering fuel. Once a drink hits 8 percent concentration or higher, stomach emptying slows significantly, increasing the risk of bloating, nausea, and cramping.
Most commercial sports drinks (Gatorade, Powerade) fall in the 6 percent range, which is right at that threshold. Fruit juice, by contrast, typically runs 10 to 12 percent carbohydrate. If you prefer juice, diluting it roughly in half with water brings it into a more stomach-friendly range.
Watch Out for Blood Sugar Drops
Drinking a sugary beverage 45 to 75 minutes before exercise can backfire. Your body releases insulin in response to the sugar, and when exercise starts on top of that insulin spike, blood sugar can plummet rapidly. This “reactive hypoglycemia” causes weakness, dizziness, and nausea, which is the opposite of what you want. It tends to happen more with smaller carbohydrate doses (around 25 grams) than with larger ones, and more when you consume them 45 minutes out versus closer to your start time.
Two ways to avoid this: either drink your carbohydrate source within 15 minutes of starting your workout, or choose something with a lower glycemic index, like milk or a smoothie with oats, which doesn’t trigger the same insulin surge.
Beetroot Juice
Beetroot juice has earned serious attention for endurance exercise. The nitrates in beets get converted into nitric oxide in your body, which widens blood vessels and makes your muscles use oxygen more efficiently. In controlled studies, drinking about 140 milliliters (a little under half a cup) of concentrated beetroot juice reduced the oxygen cost of moderate-intensity cycling by nearly 2 percent and extended time to exhaustion by 14 percent. Doubling the dose didn’t produce additional benefit, so more isn’t better here.
The catch is timing. Nitrate levels in your blood peak about two to three hours after you drink it, so you need to plan ahead. Concentrated beetroot “shots” (small, pre-measured bottles) are the most practical option because regular beetroot juice would require a large volume to hit the effective dose. Expect your urine and possibly your stool to turn reddish, which is harmless but can be alarming if you’re not expecting it.
Coconut Water
Coconut water has a reputation as a natural sports drink, and it does contain electrolytes, particularly potassium. It’s low in sugar compared to fruit juice, running about 45 to 60 calories per 8-ounce serving. Some evidence suggests it performs comparably to commercial sports drinks for rehydration. That said, it is no more hydrating than plain water, so the main advantage is taste preference and a modest electrolyte boost. If you enjoy it, it’s a fine pre-workout choice. If you don’t, water does the same job.
Protein Shakes and Smoothies
A protein shake or smoothie before a workout makes sense if you’re training first thing in the morning on an empty stomach or if your last meal was more than three hours ago. The protein helps prevent muscle breakdown during the session, while blended fruit or oats provide a slow-release energy source that avoids the blood sugar rollercoaster of straight sugar.
Keep it moderate in volume and low in fat and fiber, both of which slow digestion and can cause stomach discomfort during intense movement. A simple blend of protein powder, a banana, and water or milk, consumed 30 to 60 minutes before training, is a practical option. If your workout is mostly cardio-based and under an hour, you likely don’t need the extra protein beforehand.
What to Skip
Alcohol impairs coordination, reaction time, and hydration even in small amounts, making it the worst possible pre-workout drink. Energy drinks with high sugar loads (above 8 percent concentration) can slow fluid absorption and cause stomach distress. Carbonated beverages cause bloating and belching during movement. And milk-heavy or high-fat drinks, while fine in small amounts, can sit heavily in your stomach if consumed too close to an intense session.
Putting It Together
For most people doing a standard gym session or moderate cardio under an hour, 20 ounces of water one to two hours before, a cup of coffee if you want a performance boost, and a final 10 ounces of water 15 minutes before is all you need. For longer or more intense sessions, add a sports drink or diluted juice in that final hour. For endurance events where you want every edge, concentrated beetroot juice two to three hours out has solid evidence behind it. Match the complexity of your drink strategy to the complexity of your workout, and you’ll be well fueled without overthinking it.