Most people assume more electrolytes means better hydration. But when it comes to sodium, more isn't always better — and the science is pretty clear on why.
The Problem With High-Sodium Hydration Drinks
Many popular sports drinks and hydration mixes pack in sodium levels designed for elite endurance athletes running marathons in the heat. For the average active person — gym sessions, hikes, hot days, travel — that level of salt can actually work against you.
Here's why: your gut absorbs fluids based on a principle called osmolality — essentially, the concentration of dissolved particles (like sodium) in a liquid relative to your blood. When a drink is too concentrated (hypertonic), water is actually drawn into your intestinal tract from surrounding tissue to dilute it, reducing net fluid absorption rather than improving it.
What the Research Shows
A review by Leiper (2015) in Nutrition Reviews examined how beverage composition affects gastric emptying and intestinal absorption, and found that beverage osmolality significantly affects gastric emptying rate — high-osmolality drinks leave the stomach more slowly, delaying the point at which fluids even reach your intestines for absorption. Read the paper.
Research by Gisolfi and colleagues on intestinal fluid absorption demonstrated that hypotonic and isotonic solutions (lower sodium concentration) are absorbed more efficiently across the intestinal wall than hypertonic ones. The body simply doesn't have to work as hard to process them.
The World Health Organization's Oral Rehydration Solution (ORS) — the clinical standard for treating dehydration, developed from decades of research — specifies sodium at 75 mmol/L in its current reduced-osmolarity formulation. That's down from 90 mmol/L in the original 1975 standard, and the revision was made precisely because the lower-osmolarity version absorbed better and reduced stool output. Many commercial sports drinks marketed for "serious" athletes exceed even the older figure.
Shirreffs & Sawka (2011), writing in the Journal of Sports Sciences, noted that while sodium is essential for stimulating thirst and aiding fluid retention post-exercise, excessive sodium intake can increase plasma osmolality and work against the rehydration process for most people. Read the paper.
What This Means for You
If you're not a professional endurance athlete sweating for hours in extreme heat, you likely don't need — and may be actively hindered by — the sodium levels in many mainstream hydration products.
What you do need is a balanced electrolyte profile that supports absorption without overwhelming your system: enough sodium to stimulate uptake and retain fluid, paired with potassium and other minerals that work alongside it.
Dose Over Time Beats Dose Per Serving
Here's the practical consequence of everything above. If a more concentrated drink absorbs more slowly, then loading a single serving with 1,000 mg of sodium isn't a way to cover a long hot day — it's a way to make one bottle sit heavy in your stomach.
The better approach on a genuinely demanding day is to spread the same sodium across the hours instead of front-loading it into one glass. The American College of Sports Medicine's general guidance is 300–600 mg of sodium per hour of sustained effort. A moderate serving taken hourly lands inside that band, stays comfortably hypotonic, and keeps absorbing the whole time. A single mega-dose overshoots the concentration ceiling and then leaves you with nothing for hour three.
A Smarter Way to Hydrate
burbo Lemon Berry Hydration is formulated with exactly that in mind — 327 mg of sodium per stick, which sits at the bottom of the ACSM band and keeps the drink well inside the absorption-friendly range rather than fighting it.
To put our own numbers on the table, since we just spent an article citing ORS: a burbo stick in 16 oz of water works out to roughly 30 mmol/L of sodium — hypotonic, comfortably below the 75 mmol/L of clinical ORS, and far below the high-sodium sports formulas. That's the entire design intent. It absorbs quickly because it isn't fighting your gut.
And because the dose is moderate, you scale it by the hour rather than being stuck with whatever one serving happened to contain:
- A gym session, a hot afternoon, a travel day — one stick.
- A long, hot stretch — roughly one stick per hour of continued sweating, each in a full bottle of water rather than concentrated into less.
- Heavy, salty sweater in real heat — two in the first hour, then one per hour after. That opening 654 mg is still inside the guidance.
Two sticks a day is comfortably fine; three is our practical ceiling, since each one also carries a full day's folate and B vitamins. Beyond that, hold the hourly rhythm and take the extra sodium from food, salt tabs, or a plain vitamin-free electrolyte.
One boundary worth naming: this all describes hydration for heat, exercise, and ordinary life. Acute illness is a different problem. If you're genuinely sick and losing fluid fast, an actual oral rehydration solution is the right tool — its specific glucose-to-sodium ratio is doing something a zero-sugar mix doesn't reproduce.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. How this article was researched and written: our editorial standards.