Release Date
November 29th, 2023
Open Date
January 3rd, 2024
Due Date(s)
February 21st, 2024
Close Date
February 21st, 2024
Topic No.


Wireless, Wearable Personal Metabolic Sensor


Department of DefenseN/A


Type: SBIRPhase: BOTHYear: 2024


The Department of Defense (DOD) is seeking proposals for a wireless, wearable personal metabolic sensor. The sensor should accurately measure oxygen consumption (VO2) and carbon dioxide production (VCO2) and provide immediate feedback to improve fitness, refueling practices, body composition, and readiness. The sensor should be low-cost, lightweight (<300g), and capable of on-demand measurements. It should also have a battery life of at least 14 hours and an error rate of <10% for VO2 and VCO2 measurements. The Phase I of the project requires a proof-of-concept prototype, while Phase II involves the development of two prototypes for field use. The technology has potential applications in military training, wellness centers, and commercial fitness facilities. The deadline for proposals is February 21, 2024. For more information, visit the solicitation link.


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Military Operational Medicine


OBJECTIVE: This topic is intended for technology proven ready to move directly into Phase II and is accepting Direct to Phase II proposals only. A low-cost sensor that accurately measures oxygen consumption (VO2) and carbon dioxide production (VCO2) and provides immediate feedback that Service Members can use to improve fitness, refueling practices, body composition and readiness. If fielded, may require additional security measures. Designs that limit connectivity to Bluetooth (BT) are discouraged.


DESCRIPTION: The wide prevalence of metabolic dysfunction, emanating from low physical fitness, low physical activity, and obesity, is a public health concern and a national security issue across all service branches and phases of a military career, including recruitment, retention, training, deployment, and retirement from service [1,2].  The military needs new ways to optimize metabolic health of the nondeployed force and ensure sufficient and consistent warfighter fitness levels.

Athletes tailor their daily diet and physical activity routines to optimize metabolic health, body composition and physical performance [3]. Service members could do likewise, guided by actionable information provided by a personal non-invasive metabolic measurement and tracking device. Such a device would use a classic technique known as indirect calorimetry where volumetric rates of oxygen consumption (VO2) and carbon dioxide production (VCO2) are measured, and metabolic energy expenditure and metabolic fuel selection (fats versus carbohydrates) determined.    


Providing service members with and easy-to-use device, capable of on-demand measurements of respiratory gas exchange and determination of energy expenditure and metabolic fuel mix, would enable individuals, small military units, and the groups that support them, to design and implement personalized diet and exercise regimens.  This individualized metabolic feedback would directly support at-risk military personnel who need to meet professional standards for body composition and physical fitness and avoid the consequences of failure which can extend to separation from service. 


Existing wearable systems capable of respiratory gas exchange measurements outside of a laboratory are (a) too large, heavy (~1kg), and challenging to operate, and too expensive for routine day-to-day use by large groups of minimally trained individuals, or (b) are small and simple to use but inaccurate and/or have limited capabilities (e.g., only measure VO2, only make resting measurements).  However, new research and improvements in O2 and CO2 sensor technology suggest a compact, accurate, simple-to-use, cost-effective and scalable metabolic measurement device for use by individuals is achievable.


PHASE I: This topic is accepting Direct to Phase II (DPII) proposals ONLY. Therefore, the offeror must provide documentation to substantiate that the scientific and technical merit and feasibility described above and in Phase I has been met and describes the potential commercial applications.

Proof of feasibility includes a wireless, wearable, low-cost personal metabolic device prototype is sought to enable hands-free on-demand VO2 and VCO2 measurements, data recording, and wireless streaming to a platform-agnostic hand-held device of data to include derived metrics (e.g., metabolic energy expenditure (EE), fuel substrate mix, respiration rate). The body-worn device should be light-weight (<300g), compact, simple to use, tolerant of rain and ambient temperatures above freezing, and capable of confirming system device gas sensor calibration by referencing ambient air O2 and CO2 concentrations. Battery life should support at least 14 h of on-demand measurements. Errors of <10% in measurement of VO2 and VCO2 from rest to high intensity exercise is desired. A rigorous case and supporting data for technical and commercial viability must be presented. Evidence that the proposed solution will be viable, with adequate risk-mitigation.  A proof-of-concept breadboard or early prototype with key components identified and accuracy quantified by means of a metabolic simulator (e.g., mechanical breath simulator with injectable gas mixtures) is desirable. This Phase shall include a detailed discussion of the approach and feasibility of producing a prototype sensor for follow-on lab and human testing.


PHASE II: Expected military users of the technology are both individuals desiring to track impact of diet and exercise on metabolic health and performance as well as small-to-medium military units engaged in training or mission-planning activities. Ease of use in field environments is an important characteristic of the desired technological solution. The developed technology should be durable and readily applicable in resource-limited field conditions, be designed for at least 14 hours of use before recharging of battery. Gas sensor calibration accuracy must be able to be confirmed using ambient air reference. The offeror should consider final procurement cost as well as system operation and maintenance costs, creation of instruction manuals, definition of replacement/warranty policies, and training requirements for users. A user manual is desirable.Offeror will design, fabricate, integrate and test at least two prototype wireless, body-worn personal- use metabolic devices, and demonstrate accuracy of measured (e.g., O2, CO2, respiration) and derived parameters (e.g., Respiratory Exchange Ratio (RER), EE) using a mechanical lung simulator and injection of certified dry gas mixtures. The device must be suitable for use in field training environments where user(s) can stream data from the device, and record meta data (e.g., events) on the device, via Bluetooth Low Energy (BLE). The device shall be: 300g or less; attachable to standard Army MOLLE webbing; capable of sampling breath without headgear removal; capable of making measurements from rest (peak flow < 15 L/min) to intense exercise (peak flow > 350 L/min) with a respiratory burden <2” H2O; capable of simple field gas calibration check and recalibration; capable of detecting onset of breathing and storing all raw data measured; and capable of accurately measuring VO2 and VCO2 with average EE and RER errors of <10% and <15%, respectively, over a RER (VCO2:VO2) range of 0.7-to-1.2. Documentation should include, but is not limited to, technical reports, test data, prototype designs/models, and performance goals/results.


If experimentation with human test volunteers is planned, the offeror must provide a detailed plan for compliance with all applicable rules and regulations regarding the use of human subjects, to include Institutional Review Board approval(s).  Specifically, the proposed experimentation with human test volunteers must be reviewed for compliance with Federal, Department of Defense (DoD), and Army human subjects protection requirements and receive approval by the Office of Human and Animal Research Oversight (OHARO) Office of Human Research Oversight (OHRO) prior to implementation; this requirement derives from DoDI 3216.02 and the Defense Federal Acquisition Regulation Supplement requirement for Human Research Protection Official (HRPO) review of DoD-supported human subjects research.


Prototype Requirements: Offeror will provide two physical prototypes that include the following features and specifications: body-worn; accurate O2 and CO2 measurement of expired air; accurate volumetric measurement of inspired and expired air; calculation of accurate parameters (Respiratory Exchange Ratio and Energy Expenditure); demonstration of successful Bluetooth connectivity; demonstration of adequate device storage for up to 14 hours of minute-by-minute metabolic data collection; demonstration of adequate battery life for up to 14 hours of operation; weight of less than 300 grams; demonstration of accurate measurements ranging from rest to vigorous exercise; demonstration of ease of use; demonstration of simple calibration techniques. Error rates for measurements must be < 10% for energy expenditure (EE) and < 15% for respiratory exchange ratio (RER).


PHASE III DUAL USE APPLICATIONS: Phase III will include manufacturing planning. Markets envisioned include commercial and recreational entities responsible for performance and metabolic health with a particular emphasis on the impact of diet on metabolic fuel substrate, body glycogen (carbohydrate) stores and body composition. For both military and civilian applications the device will provide individuals with guidance regarding body weight management. optimized nutrition, and training for endurance and strength events. If the derived metrics include any diagnostic capabilities, all applicable Federal Drug Administration review and certification requirements must be met.


Commercial applications would target the clear gap between very expensive research-grade metabolic sensor systems, and inexpensive but less-capable systems with a low-cost easy-to-use metabolic sensor that provides immediate feedback to individuals seeking to improve their health and quality of life through improved physical fitness, dietary practices, and body muscle and fat mass management.  The metabolic sensor would be a key new lightweight user-friendly resource for use in fitness facilities by personal trainers designing and monitoring specialized training and weight reduction programs. Additionally, the metabolic sensor would be used by athletes and sports teams across a wide range of sporting disciplines and age. It is expected that athletes from high school to professional would benefit from a device that provides individualized feedback to maximize training and performance. The individuals that could benefit range from athletes [3] to the large group of Americans who are either prediabetic (96 million) or diabetic (37.3 million) [2]. 


Military physical training programs across the Joint services are potential beneficiaries of this product.  Likely end users of the metabolic sensor are the Armed Forces Wellness Centers (AFWC), which provide programs and services that improve and sustain health, performance, and readiness of military personnel.  The AFWC staff are active users of sophisticated wearable metabolic monitoring systems, but have a clear need for more cost-effective, accurate, and easy-to-use indirect calorimeter systems.  Another example of where metabolic sensor systems could be used by the DoD is in support of the US Army’s Holistic Health and Fitness (H2F) program.


Armed Forces Wellness Centers:

US Army’s Holistic Health and Fitness (H2F) program:



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KEYWORDS: Metabolic energy expenditure, indirect calorimetry, personal metabolic sensor, metabolic health, diet, exercise, aerobic fitness, body fat management.