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Why Wearable Hydration Monitors Might Be the Next Big Longevity Tool

You don’t have to be a high-level athlete to reap the health benefits.

a few popular hydration monitors

We’ve all seen the image: an elite athlete on a treadmill, strapped up in sensors and breathing through a face mask like they’re about to blast into space. Testing every possible biomarker is just part of the game if you’re seeking performance, but thanks to recent advancements, this tech is trickling down to amateurs, too. The latest tool to consider adding to your kit: a wearable hydration monitor. Unlike apps that remind you to take a sip of water every 15 minutes, hydration monitors work like a running watch, recording your pace to analyze in real-time the amount of fluids and electrolytes you need, and when.

Right now, hydration monitors are primarily used during sweaty activities. With a patch on the bicep or a sensor strapped to the chest, athletes can track salt loss on a long summer run or signal a coach when to blow the whistle for a water break. But the benefits aren’t just for athletes—emerging research indicates that proper hydration is crucial for overall health and can positively impact cellular health and longevity.


About the Experts

Brad Wilkins, Ph.D. is an Assistant Professor in the University of Oregon’s Human Physiology Department, the Director of the Oregon Performance Research Laboratory, and a Scientific Advisor at Nix.

Dana Cohen, M.D., is an integrated medical doctor and medical advisor for Cure Hydration.

Neda Akhavan, Ph.D., RD, is an Assistant Professor at the University of Las Vegas, Nevada, whose research focuses on understanding the role of functional foods in improving or preventing chronic diseases.


Hydration and Longevity Are Linked

We’ve all heard that old advice to drink eight cups of water a day and most of us are familiar with the symptoms of dehydration: fatigue, headaches, brain fog, constipation, etc. and see it as a short-term problem. However, recent research suggests chronic dehydration can have serious long-term consequences.

In mice, lifelong water restriction shortens lifespan and leads to organ degeneration (1). In humans, dehydration speeds up biological aging and increases the risk of chronic diseases, especially later in life (2). “Low-grade dehydration is a risk factor for diabetes, early aging, certain cancers like colon and kidney cancer, and Alzheimer’s,” says Dana Cohen, M.D.

Even small increases in plasma sodium (a symptom of dehydration) are associated with an increased risk of mortality (3). When the body’s osmosis processes are constantly fighting the effects of dehydration, risks for obesity, metabolic syndrome, hypertension, and chronic kidney and heart disease all go up (4). On the flip side, says Neda Akhavan, Ph.D., R.D., “Proper hydration positively impacts several bodily functions, including sleep quality, cognitive performance (memory and mood), and the efficacy of medications.”

Cohen emphasizes hydration’s role in detoxification. “Detoxification is the body removing waste or toxins that can accumulate from things like food, pollutants, etc. It’s imperative to detoxify to live a long healthy life and we need good hydration in order to do so,” she says.

nix hydration sensor
What a wearable hydration monitor actually looks like. (Photo: Tanner Bowden)

Why You Need a Hydration Monitor

Dehydration is both chronic and pervasive. Surveys show that roughly 50 percent of people worldwide don’t get enough fluids (4). As you age, missing the Institute of Medicine’s recommendations for daily water consumption (3.7 liters for men and 2.7 liters for women) is a lot easier, too—a five-year study found that 83 percent of women and 95 percent of men over 71 don’t meet these baselines, which become significantly more important with age (5, 6).

“As we age, our ability to sense thirst declines, which can lead to dehydration,” explains Akhavan. “This happens because brain mechanisms that regulate fluid intake, such as the hypothalamus and associated hormones like vasopressin, become less responsive.”

Thirst is also a late-stage indicator of dehydration—if you’re thirsty, you’re already past the point of needing to top up. This is why, for some, hydration monitors do a better job of keeping the body hydrated than the body itself.

Brad Wilkins, Ph.D., notes that the benefits of good hydration, like exercise, are cumulative. “We know that exercise is good for longevity. If you start at 20, it helps you reach 90. If you start at 75, it’s less impactful,” he says. So, getting an accurate picture of things early on will pay off.

Wilkins sees vast potential for people who aren’t elite athletes but exercise regularly (which is proven to increase lifespan) and don’t have access to a team of scientists and coaches.

data from wearable hydration monitors
Hydration monitor apps show sweat rate, sodium loss, electrolyte loss rate, and more. (Photo: Nix app)

Types of Hydration Monitors

Most hydration monitors measure hydration through electrodes that detect sweat on the skin, while others use light sensors, similar to heart rate monitors.

Hydration monitors come in various forms with patches, arm and chest strap units, and watches being the most popular. All work similarly, but each company uses its own proprietary algorithm to turn the data gathered into insights on sweat rate, fluid loss, and more. Some apps suggest when to drink, how much, and what electrolyte products to use while others simply give you a snapshot of your status that you can choose to react to (or not).


The Best Hydration Monitors to Buy

Nix Hydration Biosensor

The Nix Hydration Biosensor is a patch-based hydration monitor built primarily for workouts rather than all-day hydration monitoring. The rechargeable sensor snaps onto single-use patches placed on your bicep during moderate to strenuous exercise where sweat data is used to advise hydration. You can view insights in real-time via the Nix Solo app or through a paired device like a Garmin or Apple watch or cycling computer. Post-workout stats are also available to inform your strategy going forward.

Type: Patch
Usage: 4 single-use patches; reusable sensor

Pros
  • Insights are digestible in an organized app
  • Matches you with the best hydration product for your profile
  • Patches are sticky enough to last through sweaty workouts
Cons
  • Patches are single-use ($25 for refills)
  • Data isn't easy to interpret

hDrop Gen 2 Wearable Hydration Sensor

The hDrop is another hydration sensor made with athletics in mind, but is also well-suited to everyday use. The device secures to the wearer’s arm or chest with a strap—like the heart rate monitors often used by endurance athletes. hDrop’s sensor makes contact with the skin, where it can analyze sweat and, through a proprietary algorithm, provide insights on sweat rate, fluid loss, and electrolyte loss, breaking down into deeper insights on potassium and sodium levels. These insights are accessible via an app that also offers rehydration advice. The app’s “Sweat Zones” feature displays hydration levels in a speedometer-style graphic, making it easy to interpret at a glance—especially when paired with a Garmin watch.

Type: Sensor
Usage: Reusable

Pros
  • Monitor can be used outside of athletics
  • At-a-glance stats make it easy to respond to
Cons
  • The monitor could be sleeker

Flowbio S1

Flowbio’s S1 hydration monitor is made with athletes in mind, functioning alongside a heart rate monitor. The device is small and clips onto an arm or chest strap, where it analyzes sweat to inform you about fluid loss and sodium loss. The companion app takes a coaching approach to let you know how much to drink, providing specific recommendations for electrolyte products. The Flowbio S1 pairs seamlessly with popular sports apps like Garmin, Wahoo, Zwift, and more, aligning with the tools athletes already use.

Type: Sensor
Usage: Reusable with heart rate monitor or strap

Pros
  • Provides personalized hydration product recommendations
  • Integrates with most fitness devices/services
  • Easy to clean
Cons
  • App only works with iOs

Hydrostasis Geca Hydration Watch

While most hydration monitors are designed for athletes, the Geca watch is made for all-day use.The watch uses optical sensors similar to a heart rate monitor to track hydration levels and syncs the data to an app via Bluetooth. Unfortunately, the device doesn’t have a display for quick checks, but the app is clean and easy to use. A 60-plus-hour battery life makes it easy to integrate the Geca hydration monitor into your life—if you can overlook the device’s medical design.

Type: Watch
Usage: Reusable

Pros
  • Not just for analyzing workouts
  • App is well-organized
  • Feedback is continuous and real-time
Cons
  • No screen
  • Plastic case might not be durable enough for long-term use
  • Looks slightly medical

Masimo W1

While most consumer hydration monitors are made for exercise, the Masimo W1 is a wear-all-day device. It doubles as an all-encompassing health monitor that tracks heart rate, oxygen level, pulse rate variability, and sleep in addition to hydration. Masimo is a med-tech company so the W1 feels more clinical than other options. However, hydration status is displayed as an index, making it easy to decipher with a quick glance.

Type: Watch
Usage: Reusable

Pros
  • Brings hydration monitoring to the smartwatch
  • Includes monitoring of other health metrics
Cons
  • Expensive
  • May be overkill

The Bottom Line

Hydration monitors are an emerging tool in the arsenal of health monitoring devices, bringing what was once laboratory-only technology to our athletic endeavors and everyday lives. Though the tech is still new and the market is small, they’re improving. The science is clear: hydration status is an important metric to monitor for healthier aging.

About the author

Tanner Bowden is a writer who has produced travel stories, profiles, how-tos, gear reviews, and tales about technology and trends.