When someone says that they are letting their skin breathe, it means a lot more than simply that they are wearing a short-sleeve shirt, or going without lotion or other skin creams. The skin really does breathe via a process known as cutaneous respiration. This natural exchange of gases between the skin and environment happens in a wide range of creatures throughout the animal kingdom. Some animals actually get a significant percentage of their oxygen through their skin ― newborns of certain species get virtually all of their oxygen via cutaneous respiration.
You do not want to hold your breath and test it out though — us humans get no more than one to two percent of our oxygen through the skin. But even still, the gases that are expelled by our skin carry valuable information about our health. This information is useful in wound care, treating infections, monitoring hydration levels, and checking for exposure to harmful environmental chemicals, for instance. Unfortunately, the equipment needed to measure cutaneous respiration is bulky, cumbersome, and expensive, making it impractical to monitor in most cases.
A closer look at the device (📷: John A. Rogers / Northwestern University)
A group at Northwestern University is working to change that. They have just developed a wearable device that continuously measures gases coming from the skin, and it is as easy to use as a wristwatch.
The lightweight device — about the size of a small bandage — houses a series of chemical sensors inside a small chamber that hovers just above the skin’s surface. It does not make contact, which is critical for patients with fragile skin or open wounds. Instead, it uses a clever system of air valves to let gases in, then trap them briefly so the sensors can measure changes over time.
These sensors track water vapor, carbon dioxide (CO₂), and volatile organic compounds (VOCs), each of which can reveal something different. For example, elevated water vapor levels might point to a compromised skin barrier, while changes in VOCs could signal infection. In people with chronic wounds or diabetes, this kind of early detection could be life-saving.
Sensors are positioned inside the chamber (📷: John A. Rogers / Northwestern University)
The data collected by the wearable can be transmitted to a smartphone or tablet via Bluetooth, enabling clinicians to make faster decisions about treatment. In the case of wounds, that could mean earlier intervention, fewer infections, and more personalized care — not to mention less guesswork when deciding whether or not to prescribe antibiotics.
The potential applications for this device go beyond medicine. Because CO₂ and VOCs are known to attract mosquitoes, the device could be used to test the effectiveness of bug repellents, for example. It might also help researchers understand how skin creams and topical drugs are absorbed, or even measure the skin’s response to pollutants in the air.
The team is already working on the next version of their system, which could include sensors for tracking pH or detecting specific chemical markers of disease. Their goal is to create a full picture of skin health — one that is portable, affordable, and accessible to anyone. In the future, letting your skin “breathe” might not just be a figure of speech. It could be the key to better health.
