  Energy Autonomous Wearable Sensors (EAWS) have attracted a large interest due
to their potential to provide reliable measurements and continuous bioelectric
signals, which help to reduce health risk factors early on, ongoing assessment
for disease prevention, and maintaining optimum, lifelong health quality. This
review paper presents recent developments and state-of-the-art research related
to three critical elements that enable an EAWS. The first element is wearable
sensors, which monitor human body physiological signals and activities.
Emphasis is given on explaining different types of transduction mechanisms
presented, and emerging materials and fabrication techniques. The second
element is the flexible and wearable energy storage device to drive low-power
electronics and the software needed for automatic detection of unstable
physiological parameters. The third is the flexible and stretchable energy
harvesting module to recharge batteries for continuous operation of wearable
sensors. We conclude by discussing some of the technical challenges in
realizing energy-autonomous wearable sensing technologies and possible
solutions for overcoming them.
