New RRWPWater planning is an important logistical and risk management concern of road races. Until now event organizers have used guesswork and experience to estimate water needs on the race course. The Road Race Water Planner© (RRWP) app and calculator is the first to provide a strong scientific basis for easily and accurately estimating water needs, thus providing rational and actionable information to simplify logistics and improve risk management. The RRWP app and calculator can also reduce the environmental and economic impact of water planning while optimizing runner health and performance.

RRWP uses a patent pending H2Q Technology™ for accurately estimating individual exercise sweat losses and applies it to solve for the large individual variations in sweating that create uncertainty for group water planning. Group estimates are ultimately obtained from a weighted composite RRWP population of more than 3 million marathon runner finishing times. Large sample estimates from individual races reflect the theoretical RRWP population prediction distribution with fidelity in accordance with central limit theory.
runners

Millions of runners compete in thousands of road races annually. Runners are encouraged by major sports medicine organizations to know their sweating rates and to tailor drinking behaviors accordingly to avoid the potential dangers of over- and under-drinking. Unlike H2Q Technology™, RRWP is not intended for use in estimating individual runner fluid needs, nor will it prevent runners from choosing to drink above or below their actual needs. Runners must ultimately take responsibility for their drinking behaviors, but it is the responsibility of event organizers to provide the right amount of water. Therefore, planners should incorporate the use of RRWP rationally into their water planning decision making process. RRWP is a complement to the experience of event organizers and will greatly help narrow the uncertainties of water planning related to changes in weather, participant numbers, and race distance. And because it provides an accurate estimate of average runner sweat losses, it minimizes the potential for irresponsible drinking behaviors.

Required User Inputs App Outputs
  • Air Temperature
  • Number of Runners
  • Race Distance
  • Water Stations
  • Liters and Gallons of Water
  • Liters and Gallons per Water Station
  • Number of Cups*
  • Cups per Water Station
*assumes 4 fluid ounces per cup and 32 cups per gallon

cups

Accurate water estimates also reduce waste and costs.  RRWP is consistent with growing sustainability initiatives aimed at incorporating environmentally and socially responsible practices into the operational planning, preparation and execution of road races.

Road race directors and event managers can now plan with confidence the water needs of very large numbers of runners.  In a published validation study, RRWP was used to accurately predict the measured sweat losses in small groups of runners (n = 11 to 56), as well as the measured water usage in a very large group of runners (n = 27,222) at the 2017 Boston Marathon (Cheuvront et al., 2019).

Bonus features of the RRWP calculator include an estimate of the number of water stations needed for comparison to those planned.  The number of estimated water stations includes stations positioned at the start and finish.  Estimates are ultimately based on the number of runners and air temperature.  However, estimates never exceed more than one station per 1.6 km plus two (start and finish).  The RRWP calculator also estimates runner density, flow and support personnel needed at water stations using established level of service concepts and pedestrian area designs.  To read more about the bonus features, please see Cheuvront and Sollanek, 2020.

The RRWP calculator has input limits for air temperature (4 to 40 degrees Celsius) and running distance (5 to 161 kilometers).  Values entered beyond these limits will auto-convert to the closest lower or upper limit.  Enter metric or imperial units for temperature and distance (conversions will be calculated automatically).  Inputs must be entered as integers using common rounding rules (e.g., 21.6 degrees Celsius should be entered as 22 degrees Celsius; 42.2 km should be entered as 42 km).

RRWP is no longer available on the App Store®, but the calculator is free here.

Supporting Science

Cheuvront SN, Montain SJ, Goodman DA, Blanchard L, Sawka MN. Evaluation of the limits to accurate sweat loss prediction during prolonged exercise. Eur J Appl Physiol. 101(2):215-24, 2007.

Gonzalez RR, Cheuvront SN, Montain SJ, Goodman DA, Blanchard LA, Berglund LG, Sawka MN. Expanded prediction equations of human sweat loss and water needs.  J Appl Physiol, 107(2):379-88, 2009.

Gonzalez RR, Cheuvront SN, Ely BR, Moran DS, Hadid A, Endrusick TL, Sawka MN. Sweat rate prediction equations for outdoor exercise with transient solar radiation.  J Appl Physiol, 112(8):1300-10, 2012.

Charkoudian N, Kenefick RW, Lapadula AJ, Swiston AJ, Patel T, Blanchard LA, Caruso EM, Luippold AJ, Cheuvront SNPlanning military drinking water needs: Development of a user-friendly smart device application.  Mil Med, 181(9):1142-50, 2016.

 Cheuvront SN, Sollanek KJ, Fattman K, Troyanos C.  Validation of a mobile application water planning tool for road race organizers.  Med Sci Sports Exerc, 51(5):1040-1046, 2019.

Cheuvront SN and Sollanek KJ.  Considerations for standardizing fluid station practices among road races.  Strength and Conditioning Journal, 42(1): 39-44, 2020.

Copyright

The Road Race Water Planner© (RRWP) originated as an app that is protected by the United States Copyright Act and is owned by Sports Science Synergy, LLC.  All rights reserved.  The RRWP calculator is a free extension of the app.

Disclaimer

The Road Race Water Planner© (RRWP) app and calculator are intended to assist road race planners in responsibly estimating total fluid and drinking cup needs for runners.  RRWP uses a patent-pending algorithm for accurately estimating exercise sweat losses in conjunction with a weighted-composite mean of finishing times distributed among more than 3 million runners.  It is not intended for use in estimating individual runner fluid needs, nor will it prevent runners from choosing to drink above or below their actual needs.  Therefore, road race planners should use RRWP as a valid and responsible starting point from which modifications may become necessary based on independent experience and judgment.  RRWP is a complementary component to the water planning decision making process.  The Road Race Water Planner© app is not a medical app nor is the calculator intended for medical use.

Terms of Use

The Road Race Water Planner© (RRWP) app and calculator are intended to assist road race planners in responsibly estimating total fluid and drinking cup needs for runners.  RRWP is a complementary component to the water planning decision making process.  Use of RRWP for any other purpose constitutes infringement of the copyright and intellectual property rights owned by Sports Science Synergy, LLC.  By using the RRWP app or calculator, you assume all risks of copyright infringement and related liability.  RRWP and all its content may not be reproduced or used for unauthorized purposes without prior written permission, which may be obtained by submitting a written request to: Sports Science Synergy, LLC, 9 Damico Drive, Franklin, MA 02038, Attn: Dr. Samuel N. Cheuvront.