Hydration Tech is Still in the Lab
Ask most coaches, and hydration doesn't need a sensor. Thirst and urine color are perfectly good indicators—the darker urine, the more dehydration. Experts in the field note that these indicators are 100% analog, pervasive, intuitive, and reasonably accurate. Still many look to digital hydration sensors to dramatically impact sport.
How close are we to seeing hydration tech on the market?
Currently, hydration tech is mostly comprised of an immature group of technologies and user interfaces. Advancing these technologies and interfaces involves trial and error. The good news is that hardware and software platforms for building hydration-sensing systems are becoming more hackable. This means undergraduate and graduate engineers (and entrepreneurs) can prototype new devices easily and gear them to targeted user groups. Hackathon events, especially at top engineering schools, provide incentives and a setting for ideas to gestate and for the work to emerge. For example:
Last December, a smart pacifier invented by Tokyo University students won 3rd place at the Health++ Stanford hackathon. The tech monitored babies' hydration by sensing humidity levels near the lips.
In February, undergraduate electrical and mechanical engineers at Carnegie Mellon University prototyped a hydration monitor for relief workers at the school's Innovation Palooza student competition.
Neither device targets users in sports, but both can be templates for sport-focused innovation.
The Tokyo students' smart pacifier shows how hydration sensing and monitoring benefits caretakers. Athletes, and not just young athletes, frequently require watchers to oversee their health. Monitoring technology enables coaches and trainers to care for greater numbers of athletes at one time and prevent injury.
Similarly, the Carnegie Mellon sensor for relief workers provides users with a digital caretaker, one designed to augment their own awareness. By avoiding dehydration, these technology users stand to avoid the associated physical and cognitive decline, helping them to stay on task in their high-stakes work environment.
Is "Scheduled Hydration" the Killer App for Sport?
New scientific research also has the potential to shift hydration sensing needs in sports and create new product opportunities. A recent paper in Medicine & Science in Sports & Exercise by Stavros Kavouras' Hydration Lab at the University of Arkansas showed that endurance cyclists experienced performance declines when hydrating by thirst instead of following a predetermined hydration schedule.
U.S. Army researcher Robert Kenefick wrote in a January 2018 Sports Medicine journal article that: "planned drinking is optimal in longer duration activities of greater than 90 minutes, particularly in the heat; higher-intensity exercise with high sweat rates; exercise where performance is a concern; and when carbohydrate intake of 1 gram/minute is desired." He also pointed to 60-90 minute timeframes as a subjective gray zone, with no clear evidence in favor of hydration by thirst, or by schedule.
If evidence mounts that optimum performance depends on scheduled hydration then the opportunity for new sensing platforms geared toward competitive endurance athletes grows.
To be accurate, endurance athletes currently program alarms on their sport watches for hydration reminders, without using hydration sensing. Sensing would help athletes to dial in their optimal hydration schedules during training.
Optimizing Hydration Technology Is Not Easy
The user-types and changing hydration paradigms speak to the value in hydration sensing. It is important to consider ease-of-use has when it comes to consumer technology. Low-value products need to be easy to use in order to attract customers, and hard-to-use products better deliver ample, obvious value. 
Hackers who are interested in exploring hydration tech now have access to sensing hardware and user interaction software. For example, GE Global Research and Eccrine Systems are marketing commercial hydration sensing platforms. University researchers at Northwestern and North Carolina State are building hydration sensors out of flexible materials that can be joined to bandaid-like substrates for hydration monitoring.
But an easy development platform doesn't mean easy development. Optimizing individual hydration involves many, many contextual and personal co-factors. Incorporating those cofactors increases the degree of difficulty for experiments and prototypes.
Temperature is a critical cofactor. Heat has vectors that change in ambient air, in relation to physical objects, at skin surface and inside the body's core. Temperature affects sweat rate and bears directly on hydration. But heat stress at high temperatures is its own health danger, even during adequate hydration. Packaging temperature- and hydration-sensing hardware together makes sense in the use cases set in hot or sweaty environments.
Other cofactors are salt and food intake, altitude, sweat rate, percentage of salt in sweat, adiposity, and age. Each presents an opportunity to add data points that present a more detailed representation of an individual's hydration state.
These cofactors will most likely be integrated in software as stored user data available for algorithms to combine with hydration sensor data. Getting to this point would require some platform standardization, essentially a "stack" that joins hydration-sensing hardware with data storage and operations software.
Sophisticated web apps already exist without anything like a hydration-sensing stack. One such app, CORE Nutrition Planning, launched in 2017 by research nutritionist and triathlete Asker Jeukendrup to help endurance athletes manage the hydration and nutrition requirements for training and competition. The app gives user evidence-based assistance on fueling and hydration plans, replacing the typical trial-and-error approach for athletes and coaches.
Adding sensing and automation to hydration apps like CORE Nutrition Planning increases the evidence base available to inform users, adding to their scope and utility. A common hydration-sensor stack will be an important step that increases the complexity of developer experiments and prototypes. Real-time hydration management systems become viable as hydration applications become more valuable and easier to use.
In 2017, Kavouras' lab also reported in Journal of Strength & Conditioning Research that there is an absence of valid non-blood biomarkers, sourced in sweat or saliva. Identifying and validating easy-to-access biomarkers that reveal hydration state is a crucial next step. As a research problem, any jump in research productivity, like with a common hydration stack, will speed progress.
High Stakes For The Sports Performance Drink Market
As experimentation on hydration sensing increases, it should lead to greater innovation in beverage products. In recent years, "smart water" has conditioned the consumer market in the U.S. to expect a premium product. Smart water products like glacéau's smartwater and vitaminwater are main contributors to a nearly $3B market.
The hydration sensing experiments stand to inform the growing body of knowledge for beverage ingredients that contribute to optimal performance. Consumer beverages are among the easiest commercial technologies, setting a low bar for users' value, but the fundamentals, evidence of effectiveness, and viable industrial chemistry, still have to be present.
At the Sports Innovation Lab, we've identified a variety of hydration companies that produce or use technology to design, implement, and measure hydration levels for athletes:
- Aydrate: clip-on sensor for hydration bags that measures water consumption.
- Bellabeat: develops smart water bottles to track hydration.
- Graphwear Technologies: non-invasive nano-wearable patch that collects biochemical data (i.e. hydration, glucose, and lactic acid).
- H20Pal: smart bottle that automatically tracks your water intake and syncs data with your smartphone.
- Hidrate Spark: smart bottle that tracks your water intake, glows to remind you to drink, and syncs via Bluetooth to a hydration app and other connected fitness devices.
- Kenzen: smart patch measures perspiration, hydration, electrolyte levels, and skin temperature.
- LVL: fitness band that measures hydration and other activity metrics.
- Mode Sensors: develops a non-invasive wearable device that monitors hydration, specifically designed for healthcare purposes.
- Nix: single-use, wearable hydration biosensor for endurance athletes.
- Nobo: wearable device that measures an athlete's fluid and hydration levels.
- Ozmo: smart bottle records water consumption and tracks daily progress via mobile app.
- Thermos: connected bottle with smart lid monitors water intake and communicates to a connected device via Bluetooth technology.
- Sixty Hydration Monitor: measures hydration level through 4 tiers of feedback monitoring.
- Splash Hydration: MIT-developed wearable wristband sensor that uses Bluetooth-like waves to monitor hydration.
- Sukhoi: an aviation company that manufactures the SportJet, a full-scale aircraft that features a smart toilet designed for sports teams like the New England Patriots.
The hydration innovation machine is ready to roll, but the situation is not as simple as building better mousetraps. A better description might be "build something and let's see what happens." University research and hackathons are the right places to look for emerging hydration tech, places where small-scale experiments can prove and disprove insights that will in turn shape mass-market hydration product development and adoption.
1: Two technologists, Elizabeth Churchill from Google and Nadav Aharony from Globality, discussed how value and ease-of-use go together in their hour long presentation on "Product Science" at the recent South by Southwest in Austin. The central thesis: Low-value products need to be easy to use in order to attract customers, and hard-to-use products better deliver ample, obvious value.
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