Proof of concept study for the use of edge-based potassium sweat sensors
| ISRCTN | ISRCTN72685761 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN72685761 |
| Secondary identifying numbers | 2310/MODREC/24 |
- Submission date
- 07/11/2024
- Registration date
- 20/11/2024
- Last edited
- 08/07/2025
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Other
Plain English summary of protocol
Background and study aims
Our study focuses on enhancing the performance of soldiers by using a computer called UltraLYNX™ to monitor human performance. Potassium, a salt in the body, can indicate how stressed your body is. We aim to show that a potassium sensor can accurately detect potassium levels in sweat compared to blood. We will also test if caffeine affects these measurements at rest and during exercise. Additionally, we want to see if data from the potassium sensor and a heart rate monitor can be combined to create a red, amber, or green (RAG) signal to indicate how hard your body is working.
Who can participate?
Participants must be healthy adults who do not have any conditions or habits that could interfere with the study, such as intolerance to caffeine, smoking, recent drug use, or certain medical conditions.
What does the study involve?
Participants will visit the lab, where they will take either a caffeine pill or a placebo. They will undergo various tests, including measuring electrodermal activity, cognitive performance tests, and a treadmill exercise protocol. During the exercise, we will monitor heart rate, gait pattern, and other physiological responses.
What are the possible benefits and risks of participating?
Participants may benefit from learning more about their physical and cognitive performance. However, there are risks such as discomfort from blood sampling, potential side effects from caffeine, and physical exertion during the treadmill test.
Where is the study run from?
Defence Science and Technology Laboratory (UK)
When is the study starting and how long is it expected to run for?
July 2024 to July 2025
Who is funding the study?
Defence and Security Accelerator (UK)
Who is the main contact?
Dr Christopher Gaffney, c.gaffney@lancaster.ac.uk
Contact information
Public, Scientific, Principal Investigator
Health Innovation One, Lancaster University
Lancaster
LA1 4YW
United Kingdom
 ORCID ID |
0000-0001-7990-2792 |
|---|---|
| Phone | +44 (0) 1524 593602 |
| c.gaffney@lancaster.ac.uk |
Study information
| Study design | Single-centre interventional double-blind placebo-controlled randomized crossover trial |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised cross over trial |
| Study setting(s) | Laboratory |
| Study type | Other |
| Participant information sheet | 46364 DASA Participant Info Sheet.pdf |
| Scientific title | Proof of concept study for the use of edge-based potassium sweat sensors integrated with the UltraLYNX™ power and communication platform |
| Study objectives | A novel potassium sensor can reliably detect potassium levels in sweat when compared to blood. |
| Ethics approval(s) |
Approved 02/07/2024, Ministry of Defence Research Ethics Committee (DSTL Portsdown West, Salisbury, PO17 6AD, United Kingdom; +44 3001535372; DST-MODRECTeam@mod.gov.uk), ref: 2310/MODREC/24 |
| Health condition(s) or problem(s) studied | Healthy active population |
| Intervention | A single centre interventional double-blind placebo-controlled randomised crossover trial is being used to investigate a novel potassium sensor and the effect of caffeine on cognitive and physical performance Cannulation, electrodermal activity and cognitive performance tests Upon entering the lab, subjects will be cannulated using a standard antecubital cannula. The study visits will involve the ingestion of either a 200mg caffeine pill or a placebo pill (double-blinded, randomised). After administration of either the placebo or caffeine pill, participants will wait for 45 minutes whilst undergoing monitoring to allow the caffeine to become bioavailable. Participants will have electrodermal activity measured using electrodes on the hand or wrist . This involves connecting two electrodes to the non-dominant hand (typically the index and middle finger) or the wrist. Participants will remain seated and still whilst measurements are taken. Participants will then undergo a cognitive performance test battery on a laptop comprising of tests to measure attention, memory, and reaction time skills. We will use NIH toolbox cognitive tests . Participants will complete: (1) Flanker Inhibitory Control and Attention Test; (2) List Sorting Working Memory Test and (3) Oral Symbol Digit Test (3 minutes). Stimuli are presented digitally (on the laptop) but oral responses are given, and the experimenter records the responses. Preparation for treadmill testing Once complete, participants will don a Hans-Rudolph mouthpiece for breath-by-breath analysis and the straps around the head will be secured by a researcher, Polar heart rate chest strap, a weighted vest (20lb/9.07kg for every participant) and will be connected to an online gas-analysis system. The side of the treadmill will be fitted with the infra-red OptoJump system to monitor changes in gait pattern between trials. Marching protocol Participants will then move on to complete a simulated march and running protocol on the treadmill, designed to mimic the load carriage of fast marches in the British Army at the time, and an offensive/defensive fire and manoeuvre-based task. The protocol comprises of 20 minutes walking at 5.1km/h then 40 mins walking at 6.5 km/h at a 1% gradient all whilst carrying a 9.07kg (20lb) load within a weighted vest. At 60 mins and still at a 1% gradient, participants then walk for 1 min at 2.5 km/h before the gradient is increased to 3% and participants complete 8 x 9s shuttle runs at 11 km/h with inter-shuttle rest periods of 11s at 2.5km/h. Sampling and measurements during the marching protocol Ratings of perceived exertion will be taken at 10-minute intervals throughout the marching protocols and at the end of the shuttle runs using the Borg 6-20 scale. Similarly, glucose and lactate will be measured at 10-minute intervals throughout using a finger prick capillary blood sample and analysis on a Biosen EKF point of care glucose/lactate analyser. Finally, we will assess muscle performance through the measurement of peak isokinetic torque using an isokinetic dynamometer, both before and after the 62-minute treadmill protocol. Whole blood will be sampled at the end of each stage from a peripheral venous cannula. Gas exchange including O2, CO2 and minute ventilation (VE) will be measured throughout the marching protocol using a Cortex Metalyzer breath-by-breath gas analysis system. |
| Intervention type | Supplement |
| Primary outcome measure | Potassium Levels - measured via novel potassium sensor at rest and during exercise via sweat and from blood |
| Secondary outcome measures | Effect of caffeine on cognitive and physical performance: 1. Electrodermal activity is measured using electrodes on the hand or wrist at 45 minutes post-administration 2. Attention is measured using the Flanker Inhibitory Control and Attention Test at 45 minutes post-administration 3. Working memory is measured using the List Sorting Working Memory Test at 45 minutes post-administration 4. Reaction time is measured using the Oral Symbol Digit Test at 45 minutes post-administration 5. Breath-by-breath analysis is measured using a Hans-Rudolph mouthpiece and online gas-analysis system during treadmill testing 6. Heart rate is measured using a Polar heart rate chest strap during treadmill testing 7. Gait pattern is measured using the infra-red OptoJump system during treadmill testing 8. Ratings of perceived exertion are measured using the Borg 6-20 scale at 10-minute intervals throughout the marching protocol and at the end of the shuttle runs 9. Glucose is measured using a finger prick capillary blood sample and Biosen EKF point of care glucose/lactate analyser at 10-minute intervals throughout the marching protocol 10. Lactate is measured using a finger prick capillary blood sample and Biosen EKF point of care glucose/lactate analyser at 10-minute intervals throughout the marching protocol 11. Muscle performance is measured using an isokinetic dynamometer before and after the 62-minute treadmill protocol 12. Gas exchange (O2, CO2, minute ventilation) is measured using a Cortex Metalyzer breath-by-breath gas analysis system throughout the marching protocol |
| Overall study start date | 02/07/2024 |
| Completion date | 01/07/2025 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 35 Years |
| Sex | Both |
| Target number of participants | 20 |
| Total final enrolment | 20 |
| Key inclusion criteria | 1. Male or female 2. Aged 18-35 years 3. Pass UK military physical tests |
| Key exclusion criteria | 1. Any intolerance or avoidance of caffeine 2. Any prescribed medication 3. Smokers (smoking defined as more than 100 cigarettes throughout lifetime) 4. Vaping defined as any use in last 7 days 5. Liquorice consumption within the last 7 days 6. Recreational drug use in the last month, including, but not limited to, cannabis and cocaine 7. Any medical condition that would prevent entry into army, navy or air force 8. Phobia to needles 9. Allergy or insensitivity to materials used in the study (e.g., adhesive) 10. Recent musculoskeletal injury (within the last 3 months) 11. Non-English speakers 12. Pregnancy 13. Atrial fibrillation 14. Any findings that the Clinical research fellow believes affect the integrity of study data or the safety to conduct tests |
| Date of first enrolment | 18/11/2024 |
| Date of final enrolment | 25/06/2025 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
Lancaster
LA1 4YW
United Kingdom
Sponsor information
Government
Porton Down
Salisbury
SP4 0JQ
England
United Kingdom
| Phone | +44 1980 950000 |
|---|---|
| centralenq@dstl.gov.uk | |
| Website | https://www.gov.uk/government/organisations/defence-science-and-technology-laboratory |
"ROR" |
https://ror.org/04jswqb94 |
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- DASA
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 01/03/2026 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Not expected to be made available |
| Publication and dissemination plan | Planned publication in a peer-reviewed journal |
| IPD sharing plan | The datasets generated during and/or analysed during the current study will be available upon request from Dr Christopher Gaffney (c.gaffney@lancsaster.ac.uk). |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | 14/11/2024 | No | Yes | ||
| Statistical Analysis Plan | 14/11/2024 | No | No |
Additional files
Editorial Notes
08/07/2025: The date of final enrolment was changed from 01/07/2025 to 25/06/2025. Total final enrolment added.
07/03/2025: The following changes were made:
1. The overall study end date was changed from 01/03/2025 to 01/07/2025.
2. The recruitment end date was changed from 18/03/2025 to 01/07/2025.
08/11/2024: Trial's existence confirmed by Ministry of Defence Research Ethics Committee.
