Measuring sweat for things like pH levels, lactate, and blood sugar during exercise and reading them in an app. Researchers from Northwestern University are making it a reality.
Sweat is Knowledge
You can glean information from sweat about the state of your body. For example, it’s possible to see how a body responds to training through so-called ‘biomarkers’. Simple data like the amount of sweat can indicate your hydration status. From sweat, pH levels can also be measured. This is interesting because acidity can be an indicator of the amount of electrolytes in someone’s blood (the amount of sweat also affects this). Glucose levels can indicate if you still have enough sugars to provide energy. Lactate can indicate the degree of acidosis.
So, this is useful information for athletes. For example, for a personal hydration plan. Knowing exactly how much, what, and when to drink for optimal performance. However, extracting this information from sweat in practice was quite cumbersome and expensive. This involved collecting sweat with a sponge-like material and then performing measurements with laboratory equipment.
Sweat Patch
The researchers from Northwestern University aimed to change this [1]. They previously tested flexible material that could be securely attached to the skin and was equipped with electronics. For sweat analysis, the challenge was in collecting the fluid and performing precise biochemical analyses.
The soft, flexible patch they developed for this purpose is placed on the forearm or back and can be worn for several hours. Due to the direct way in which sweat is collected and analyzed, the patch is expected to provide even more information than current methods.
Research on Accuracy and Durability
The patch collects sweat in four reservoirs. Chemical reactions take place in these reservoirs resulting in a certain color that is indicative of the status of the mentioned biomarkers (pH, chloride, lactate, and glucose). Holding the patch in front of your mobile phone activates an app that instructs the camera to take a photo. The app then translates the different colors into the desired data. Alternatively, sweat can be collected for later analysis in a laboratory.
In a study to test the accuracy and durability of the patch, it was given to two groups of cyclists. One group cycled indoors under controlled conditions, while the other group participated in an outdoor race under varying conditions.
In the first group, the accuracy of the patch was compared to measurements made using the traditional method. The results were found to be the same. The group cycling outdoors mainly served to test durability, which was also successful. The patches remained in place, did not leak, and provided the desired information.
Knowledge is Power
This research is another example of easier ways to find out what’s happening in the body. Earlier, I wrote about the possibility of determining what someone has eaten through urine. I will also write an article this week about a new method for measuring the amount of vitamins in the body through tears.
The method described here for collecting sweat is particularly interesting because I envision a future where this technology is incorporated into wearables. Then, with devices like your Fitbit or Apple Watch, you can measure much more than just heart rate and steps.
The more data we can obtain and the easier it becomes, the better we can act on it and optimize our training (and nutrition).
Reference
- A. Koh, D. Kang, Y. Xue, S. Lee, R. M. Pielak, J. Kim, T. Hwang, S. Min, A. Banks, P. Bastien, M. C. Manco, L. Wang, K. R. Ammann, K.-I. Jang, P. Won, S. Han, R. Ghaffari, U. Paik, M. J. Slepian, G. Balooch, Y. Huang, J. A. Rogers. A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat. Science Translational Medicine, 2016; 8 (366): 366ra165 DOI:
- https://www.science.org/doi/10.1126/scitranslmed.aaf2593
