Hydration Highlight

I’m not sure where you live in the world, readers, but I know we’ve had some wicked hot days here in Ontario - our Victoria Day weekend back in May was wild (and all I could think about drinking was ginger ale, just gallons and gallons of ginger ale).

In hot weather like that, and when physical activity is part of being outdoors, hydration becomes essential. Now in the world of wellness, water is often treated as the "easy" win to replenish sweat losses for athletes and active individuals. We’re told to carry a gallon jug, set phone reminders, and aim for the mythical "eight glasses a day." I know I’ve been the type to recommend reminders for many of my patients and clients so they can space fluid intake out over the whole day, and in my own athletic training trying to track intake to make sure I hit the final total by the end of the day. But for those living an active and high-demand lifestyle, hydration isn't just about volume - it’s about precision!

True hydration is a biological symphony (and if you know me, you know I’m thinking about Bugs Bunny directing the orchestra) involving mineral balance, timing, and cellular absorption. When you hit the so-called sweet spot, your focus sharpens, your endurance climbs, and your recovery time plummets. And you’ll notice when you miss it, with drops in cognitive and physical performance even with the smallest deficits.

To really understand hydration, we have to look past the drinking of fluids and into the cells. The cell requires a balance of both water and electrolytes, which are heavily involved in cellular processes, nerve function and metabolism. If there are lots of electrolyte or salt losses, and all we add back is massive amounts of plain water, we run the risk of hyponatremia, or low sodium levels, that can become unsafe. Electrolytes need to be added in these situations to ensure cells remain intact and body function isn’t compromised.

Which common minerals are electrolytes? We see marketing for electrolytes for practically every fluid out there, especially when it’s marketed to active people or athletes (or the bull of biohacking). It’s helpful to know what you’re looking for on a label.

Sodium is the primary driver of thirst and fluid retention. For athletes, it’s the most lost mineral in sweat. It maintains blood pressure and ensures your muscles can contract and relax properly. Potassium is the internal counterbalance to sodium - while sodium stays mostly outside of the cells, potassium lives inside. Together, they create a "pump" action that allows for nerve signaling and heartbeat regulation. And finally, think of magnesium as the relaxation mineral. Magnesium is involved in over 300 enzymatic reactions including energy production of ATP (the “currency” that the human body spends for reactions.

How do you know if you’re thirsty, if you don’t feel thirsty?

Brain fog can be a common one, and it makes sense - the human brain is approximately 75% water, and we use a lot of water in a lot of chemical reactions for body and brain function. While it’s tempting to reach for a coffee when energy levels start to dip, a glass of water might serve a better purpose.

Checking urine colour is another option, even though it’s not the most glamorous. The frequency of washroom visits can be a starting indicator, and a quick check for colour before flushing gives more detail. Aim for a pale yellow straw color. If it’s clear, you’re likely over-hydrated and flushing out electrolytes; if it’s dark like apple juice, your kidneys are struggling to conserve fluid and extra water is needed. If you’re taking a multivitamin, vitamin C or B-complex supplement, you’ll notice urine is neon yellow in colour (thanks B and C vitamins!), but the overall tone is important - neon yellow but light, or intensely yellow and dark.

And finally, skin elasticity can be a helpful metric. If you pinch the skin on the back of your hand and it stays up for a second before smoothing back down, your interstitial fluid (the fluid between the cells) level may be low and it’s time to hydrate!

You’ve probably noticed that your hydration status has some variation to it, and this is common. Hydration isn’t a flat line with a single 24 hour goal, it’s a curve that follows our daily rhythm and our changing activity level. And the kidneys don’t reset at the end of the day, they’re always filtering.

We lose a lot of water through breathing, and while this isn’t a big deal throughout the day because we can drink as we go, overnight this can pose a barrier to optimal hydration. A big glass of water before or alongside your morning coffee can replace losses and get you started for the day.

Hydration during activity feels pretty obvious, but pre-loading hydration is important too. Fluid intake 60-90 minutes before high intensity activity allows for filtering so you’re not running to the bathroom mid-event, and amps up fluid status before big losses begin.

This might not surprise anyone, but the menstrual cycle also impacts fluid status. During the luteal phase, core temperatures are higher and increased sweating occurs. This is the time to bump up both fluid and electrolyte intake, and focus on options that don’t increase symptoms like anxiety and bloating (read: limit high caffeine intake, and high sugar-sweetened carbonated beverage intake).

Don’t be afraid to also expand your idea of water - we can also eat it! The fluid found in raw fruits and vegetables often comes packaged with fiber and natural minerals that slow down absorption. Watermelon, cucumber, strawberries and celery are all amazing options to keep in rotation during the warmer months.

There is no "perfect" amount of water for everyone. And your ideal amount of water intake on one day will be vastly different on another - an individualized assessment with a Registered Dietitian (RD) can help you determine the best amount for you, and make adjustments for factors like injury or illness, activity level and pregnancy or lactation.

Hydration is a fantastic foundation to build all other health goals on - we can’t survive without water! Becoming more intentional about your fluid intake, and troubleshooting as needed, is a game-changer for better energy levels, better exercise performance, and better cognitive function.