December 9, 2025
This guide breaks down exactly how much to drink, what to drink, and when to take electrolytes on active days—whether you’re lifting, running, playing sports, or just on your feet for hours.
Most active people need about 0.4–0.8 liters of fluid per hour of exercise, adjusted for sweat rate and climate.
Electrolytes matter most for workouts over 60–90 minutes, heavy sweaters, hot/humid conditions, or multiple sessions per day.
Sodium is the priority electrolyte; aim for 300–800 mg sodium per liter of fluid during longer or hotter workouts.
This guide uses current sports nutrition research, practical guidelines from exercise physiology organizations, and real-world practices from endurance and strength athletes. It breaks hydration into simple chunks: daily baseline needs, pre-workout, during-workout, and post-workout strategies, plus how to adjust for heat, sweat rate, body size, and goals like fat loss or performance.
Under-hydrating can sap power, endurance, and concentration; over-hydrating without electrolytes can dilute blood sodium. Getting the right balance of fluids and electrolytes helps you perform better, recover faster, avoid headaches and cramps, and feel steady instead of drained on active days.
A practical starting point for most active adults is about 30–40 ml of fluid per kg of body weight per day, including all drinks and water-rich foods. For a 70 kg person, that’s roughly 2.1–2.8 liters per day. This baseline covers normal living plus light activity but not intense training or extreme heat. Thirst is helpful but imperfect—aim for steady intake across the day rather than chugging large volumes at once.
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Use urine color as a quick real-world gauge. Pale straw or light yellow usually suggests good hydration. Very dark yellow or amber can indicate you’re under-hydrated, especially if you haven’t had certain supplements (like B vitamins) that darken urine. Crystal-clear urine all day may mean you’re drinking more than needed and potentially diluting electrolytes.
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Aim for about 5–7 ml of fluid per kg body weight 2–3 hours before exercise. For a 70 kg person, that’s roughly 350–500 ml. This window allows you to absorb and excrete excess fluid before training. If your urine is still dark 60–90 minutes before exercise, add another 200–300 ml and reassess.
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In the 15–30 minutes before your workout, a small top-up of 150–250 ml can help if you haven’t had fluids in the past hour, especially in hot or dry environments. Avoid chugging large amounts immediately before hard efforts to reduce sloshing and GI discomfort.
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Weigh yourself nude or in dry minimal clothing right before exercise and again immediately after, towel-dried, noting how much you drank. Every 0.5 kg lost is about 0.5 liters of sweat, not counting drinks. Example: You lose 1.0 kg and drank 0.5 liters; your sweat rate is roughly 1.5 liters per hour for that session. Repeat in different conditions to understand your range.
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Aim to finish most workouts with no more than about 2% of your body weight lost. For a 70 kg athlete, that’s roughly 1.4 kg. Minor loss is acceptable and normal; trying to finish at exactly your starting weight can lead to over-drinking. Consistent large losses suggest you should increase fluids or drink earlier.
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Electrolytes—especially sodium, plus potassium, magnesium, and calcium—help control fluid balance, nerve signaling, and muscle contractions. When you sweat, you lose water and electrolytes, mainly sodium. If you only replace water during long or hot sessions, blood sodium can dilute, increasing risk of headaches, nausea, or hyponatremia in extreme cases.
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Electrolytes are particularly useful if you train longer than 60–90 minutes, sweat heavily (visible salt on clothes or skin), do back-to-back sessions or tournaments, or exercise in hot/humid conditions. For short, light sessions under an hour in cool conditions, water is usually enough if your overall diet is well-salted.
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Most sports science focuses on sodium because sweat is sodium-rich. A practical target for long or hot workouts is about 300–800 mg sodium per liter of fluid, adjusted for how salty a sweater you are. Heavy and salty sweaters or ultra-endurance athletes might need more, often via sports drinks, electrolyte powders, or salt capsules supervised by a professional.
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Potassium losses in sweat are smaller than sodium, and most people get enough from food. Bananas, potatoes, yogurt, oranges, beans, and leafy greens are all good sources. Many balanced electrolyte mixes include 100–300 mg potassium per serving, which is typically adequate for most athletes.
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For long or hot sessions, include some sodium in your pre-exercise meal or drink: for example, a normal salted meal plus 250–500 ml of a light electrolyte drink in the hour before. This helps retain fluid and reduces early-session drops in blood volume. If you’re salt-sensitive or have blood pressure concerns, discuss sodium strategy with a healthcare provider.
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For sessions over 60–90 minutes, especially in heat, include electrolytes in the fluid you’re already drinking. Use a product or homemade mix that delivers roughly 300–800 mg sodium per liter, sipped steadily rather than in big gulps. Match concentration to your stomach tolerance; higher concentrations can bother some people at race pace.
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Most lifting sessions of 45–75 minutes are well-covered by your baseline hydration, plus 250–750 ml of water or a light electrolyte drink during training. Over-drinking can cause bloating and reduce comfort under heavy loads. Focus on starting the session well-hydrated and sipping between sets, not chugging right before heavy attempts.
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Hydration affects performance and appetite. Mild dehydration can feel like hunger or fatigue. Use water or calorie-free electrolyte drinks around workouts to support training quality without unnecessary calories. However, if you’re training hard or long, do not restrict fluids to “weigh less”—this is mostly water loss, not fat loss, and can impair performance and recovery.
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The ideal hydration and electrolyte plan is individual: body size, sweat rate, climate, sport type, and training length all shift the right amount, concentration, and timing. Simple tools like pee color, pre/post body weight, and how your stomach feels are more useful than rigid one-size-fits-all rules.
Sodium is the primary lever to pull as your training becomes longer, hotter, or more intense, but you rarely need extreme amounts if your daily diet is solid. Focus first on consistent daily fluids, then adjust sodium and total intake around your longest or sweatiest sessions for the biggest performance and comfort gains.
Frequently Asked Questions
Common signs include unusually high perceived effort, dry mouth, headache, dizziness, drop in pace or power at the same effort, and very dark urine afterward. Large body weight loss (more than about 2% of starting weight) after a session is another strong clue that you didn’t drink enough.
Yes. Over-drinking plain water, especially during long events, can dilute blood sodium levels and in rare cases cause hyponatremia. Symptoms include nausea, headache, confusion, and swelling in hands or feet. To reduce risk, avoid forcing fluids, use thirst plus guidelines, and include sodium during long or hot sessions.
No. For most workouts under 60 minutes in moderate conditions, water is usually enough if your daily diet includes normal amounts of salt and a variety of foods. Sports drinks become more useful as exercise gets longer, hotter, harder, or when you need carbs and electrolytes together and can’t easily eat food.
A practical option is about 500 ml water, a pinch of salt (roughly 1/8–1/4 teaspoon, adjusted to taste and needs), a squeeze of lemon or lime, and optionally a teaspoon of sugar or honey for flavor and quick carbs. This won’t be as precise as commercial products but is sufficient for many active people.
Yes, but not by as much as you might think. You may feel less thirsty in the cold, yet still sweat under layers. You can usually reduce fluid intake slightly compared with hot weather, but don’t stop drinking altogether. Use the same tools—urine color, body weight changes, and performance—to fine-tune.
Hydration and electrolytes work best when you individualize them: start with a steady daily fluid baseline, then adjust amounts and sodium around your longest, hardest, or hottest sessions. Use simple feedback—thirst, urine color, body weight change, and performance—to refine your plan over time so you feel stable, strong, and clear-headed on every active day.
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Aim to drink regularly rather than relying on big catch-up drinks. For many people, this looks like 250–400 ml with meals and smaller sips between meals. Add more on days with long commutes, air-conditioned or heated environments, or lots of talking (coaches, teachers, sales). This steady approach keeps blood volume stable and prevents mid-afternoon crashes and headaches.
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Most active people do well with about 0.4–0.8 liters of fluid per hour of moderate to hard exercise. Smaller individuals or cool conditions lean toward 0.4 L; larger individuals, high intensity, or heat lean toward 0.8 L. This is a starting range—not a rule. Adjust based on sweat rate, stomach comfort, and body weight change.
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A simple method is to drink about 1–1.5 liters of fluid for every kilogram of body weight lost during exercise, spread over the next 2–4 hours. If you don’t track weight, drink to satisfy thirst plus roughly 500–750 ml more than usual after particularly sweaty or long sessions and include some sodium in fluids or food.
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Sweat rate rises in heat, humidity, direct sun, and with heavy gear or protective equipment. You might lose 0.5 L/hour in a cool indoor gym but 1.5–2.0 L/hour in a hot outdoor match. Re-check sweat rate when seasons change, you travel to new climates, or training load jumps significantly.
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A normal mixed diet with salted meals, fruits, and vegetables covers electrolyte needs for most light to moderate exercisers. On particularly active days, especially with long or intense sessions, it can be more efficient and gut-friendly to sip an electrolyte drink rather than trying to eat large salty meals before or during training.
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Magnesium and calcium play roles in muscle contraction and relaxation. Sweat losses are modest, but some athletes with poor dietary intake or very high training loads benefit from ensuring adequate intake through food or supplements. Nuts, seeds, whole grains, dairy, and leafy greens are useful sources. Excess magnesium at once can cause GI upset, so keep supplement doses moderate.
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You can meet many electrolyte needs with everyday foods: salted meals, broth, olives, pickles, fruit, yogurt, potatoes. Sports drinks, tablets, and powders are convenient when eating is impractical, when you need precise sodium amounts, or when you want low-fiber, stomach-friendly options before or during hard efforts.
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Post-exercise, pair fluids with sodium-containing foods or drinks to speed rehydration. This can be as simple as a normal salted meal plus water, or a recovery drink that includes electrolytes along with carbs and protein. If you’ve lost a lot of sweat (salt marks on clothes, crust on skin), keep some electrolytes in your fluids for several hours afterward.
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For runs, rides, or swims longer than 90 minutes, plan specific hydration and electrolyte checkpoints. Practice your race fueling in training using the same products and amounts. Aim to start events well-hydrated, then drink to a plan informed by your sweat rate, adjusting slightly for weather and pace.
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Team sports combine high intensity with limited drink breaks. Use pre-hydration and pre-electrolytes more aggressively, then take advantage of every timeout, substitution, and halftime to sip. Slightly higher sodium drinks can be helpful when sweat losses are high and breaks are short.
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