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Controlling blood pressure has never been as easy. The graphite wearable offers greater accuracy, speed and is 24/7..

What is the measurement of blood pressure?

With each beat, the heart pumps blood towards the arteries, the measurement of blood pressure calculates the strength or pressure of the passage of the blood. This measurement takes account of two values:

• Systolic blood pressure (the first number at the top) measures the pressure on the arteries when the heart beats.
• Diastolic pressure (the second number at the bottom) measures the pressure on the arteries when the heart is resting between heartbeats. 

When blood pressure is high (hypertension) it can cause health problems such as heart attacks or strokes, although fortunately this is not always so. Blood pressure measurement enables early diagnosis, so that it can be treated before it causes serious complications.

However, although less common, it is also possible to suffer from low blood pressure, or hypotension, which causes symptoms such as:

• MDizziness and confusion
• Nausea
• Cold and sweaty skin
• Paleness
• Fainting
• Weakness

To find out your blood pressure levels, you need to know the systolic and diastolic values and, normally, people who are liable to suffer changes in their blood pressure tend to control and monitor their values and visit the doctor if these reach worrying levels. Different devices are used to ensure accuracy and complete information, and people can also take the measurements themselves without leaving home. But the real revolution has arrived with a discovery by a group of researchers from the USA.

Graphene tattoos

Researchers from the University of Texas have developed an intelligent tattoo, an electronic tattoo that monitors blood pressure over time. Its uniqueness is that it is made of graphene, a bi-dimensional material which has revolutionised the pharmaceutical and medical sectors. Currently, it is one of the most neccesary and “powerful” materials.

The wearable has the same features as a blood pressure monitor, but it is permanently incorporated into the body by means of a tattoo.

 “Blood pressure is the most important vital sign that we can measure, but methods for doing so outside the clinic are very limited”,

commented Deji Akinwande, a doctor in the Departament of Electrical and Computer Engineering at the University of Texas, who is leading the project.

The e-tattoo enables a more exhaustive and constant control of blood pressure. It includes twelve invisible graphene strips placed in two parallel lines along the arteries in the forearm. The external strips send electrical signals to the inner arm, while the internal strips detect changes in the blood flow, which enable the measurement of pressure and an analysis of the body’s response. This process is known as bioimpedance. The researchers created an automatic learning model to analyse the connection and obtain accurate blood pressure readings.

To demonstrate its efficacy, the group of researchers tested six volunteers who measured their blood pressure at different times: under stress situations, when sleeping, when exercising, at work, walking, studying, cooking, etc. Also, to prevent the participants being influenced by this, they did not know when their blood pressure was being measured.  

Currently, a large part of the hardware required for registering and analysing the data from the tattoo is nearby and connected by a cable, although wireless connections can be explored in the future. The researchers also want to connect the tattoos with an intelligent watch over them, which is another of the most well-known wearables on the market.

Intellingent watches vs e-tattoos

We have previously discussed intelligent tattoos and the fact that they provide a series of advantages, although they are not the only intelligent device that has revolutionised e-health. Intelligent wound dressing for chronic patients, or elements of the home that have become long-distance doctors, among these, the bath mat or the toilet that analyses stools. But health monitoring has been trending for years in a more commonly-known ways, as in the intelligent watch. No one is surprised by the fact that these can measure heartbeats or monitor sleep quality, all through some metallic sensors based on sources of LED light that shine through the skin.

Despite their great advances, unlike the tattoo, the smartwatch is not equipped to measure blood pressure. This is because it is not fixed and, as it can slide around on the wrist, the readings are not accurate. The e-tattoos have a considerable advantage due to their graphene qualities and the way they are connected to the skin.