Why do you need electrolytes?
The science
Electrolytes are minerals like sodium, potassium, and magnesium that carry an electric charge. Sodium lives mostly outside your cells and controls how much water moves in and out of them. Potassium does the same job from the inside. Between them, they run your fluid balance and fire the electrical signals that move your muscles and keep your heart beating on schedule (NIH/NCBI, StatPearls).
So what
This isn't a gym thing. You're losing electrolytes right now, sitting still, reading this. Sweat during a workout, sure, but also a hot commute, a long shift, a stressful meeting, one too many coffees before noon. Water alone doesn't fix that. It dilutes what's left instead of replacing what's gone, which is why chugging a bottle of plain water on a rough day sometimes makes you feel worse, not better.
Bottom line
Electrolytes aren't a performance hack. They're plumbing, the basic stuff your body runs on every single day, not just the days you exercise. That's the whole idea behind daily hydration: top up before you feel it, not after.
Next: When is the best time to take electrolytes?
Do electrolytes actually help with hangovers?
The science
Do electrolytes actually help with hangovers? Alcohol makes you pee out more fluid than the same volume of water would. A study that had healthy men drink beer instead of water tracked urine output and blood markers over twelve hours, and found significantly higher fluid loss in every beer condition, along with signs of more sodium lost along with it. The effect showed up early and then partly reversed later in the session, but the net loss was still measurably higher than plain water drinking (PubMed, Sailer et al., American Journal of Physiology).
So what
This is why a big night out leaves you drier than the number of drinks alone would suggest. Replacing the wine or the six beers isn't enough, your kidneys pushed out extra fluid too, because alcohol briefly switches off the hormone that normally tells your body to hold onto water. That's a purely mechanical effect, it happens whether you're a seasoned drinker or someone who had two glasses of wine at a work thing. Day two of a hangover, the headache, the flat mood, the fog that makes your 9am meeting feel hostile, overlaps a lot with plain dehydration symptoms, on top of whatever else alcohol itself is doing to you overnight.
Bottom line
Electrolytes won't cure a hangover on their own, and they don't actually help with hangovers by speeding up how fast your liver processes alcohol. But if part of how rough you feel the next morning comes down to fluid and sodium loss, replacing that is a reasonable, unglamorous thing to do before bed or first thing when you wake up. It's not a fix. It's just addressing one piece of a bad morning that actually has decent evidence behind it, rather than guessing.
Back: How much sodium do you actually need?
How much sodium do you actually need?
The science
How much sodium do you actually need? The US Adequate Intake for sodium sits at 1,500mg a day for adults, according to the National Academies' dietary reference intake report. That number assumes you're at a normal room temperature and not doing anything strenuous. The same report says people in the heat or doing intense exercise likely need more, but stops short of giving a single number, because sweat rates vary so much from person to person. Two people doing the identical hour of exercise can lose very different amounts of sodium through sweat (NIH/NCBI, National Academies DRI report).
So what
That 1,500mg baseline was built for someone sitting at a desk in an air-conditioned office, not someone doing a hot commute, a warehouse shift, or training for anything. Sweat isn't just water, it carries salt out with it, and how salty your particular sweat is doesn't show up on any supplement label. There's no universal correct number here. A desk job and a landscaping job in July aren't the same starting point, even for two people the same size. It's also why sports drinks built for elite athletes look nothing like what a normal day needs. Most of us aren't running marathons, we're just trying not to run a deficit by 3pm.
Bottom line
There's no single answer to how much sodium you actually need, but most people aren't chronically low sitting at a desk. If you're properly sweating, whether that's an actual workout or just a stinking hot day outside, your real number is higher than the office baseline. The honest approach is matching your intake to what you're actually losing that day, not chasing a fixed number from a guideline or a product label.
Back: Why does mild dehydration make you feel tired? | Next: Do electrolytes actually help with hangovers?
Why does mild dehydration make you feel tired?
The science
In one study, men who lost about 1 to 2% of their body weight in fluid, a level you could hit without ever feeling properly "thirsty," showed measurably higher fatigue and tension, plus worse working memory, than when they stayed hydrated (PubMed, Ganio et al., British Journal of Nutrition).
So what
1 to 2% doesn't sound like much. For someone around 70kg, that's under a kilogram and a half of fluid, easy to lose over a normal day: talking a lot, sitting in a warm office, skipping water because you were busy. No dramatic sweating required. That fog that hits around 3pm and gets blamed on lunch or bad sleep? Sometimes it's just this.
Bottom line
Dehydration isn't the only cause of fatigue, and electrolytes aren't a cure for being tired. But it's a cheap thing to rule out. If you're flagging by mid-afternoon and can't remember your last proper drink, that's worth fixing before you reach for more coffee.
Back: When is the best time to take electrolytes? | Next: How much sodium do you actually need?
When is the best time to take electrolytes?
The science
A randomized trial comparing different rehydration drinks found that electrolyte content, especially sodium, was the single biggest factor in how much fluid your body actually holds onto. Drinks with sodium in them were retained significantly longer than the same amount of plain water (PubMed, Maughan et al.).
So what
There's no secret golden hour here. The honest answer is: whenever you're already running a deficit. That's first thing in the morning, after seven or eight hours of not drinking anything while you sweat through the sheets and breathe out moisture all night. It's also after a hard sweat, a day in the heat, or the morning after wine did its diuretic thing to you. Matching your intake to when you're actually losing fluid matters more than hitting some specific hour on the clock.
Bottom line
If you only remember one time, make it the morning. You're already behind before you've had a sip, so it's the easiest habit to keep. Have it before your coffee, not as an afterthought once you're three cups in.
Back: Why do you need electrolytes? | Next: Why does mild dehydration make you feel tired?