Abstract—An increase in world population along with a
significant aging portion is forcing rapid rises in healthcare
costs. The healthcare system is going through a transformation
in which continuous monitoring of inhabitants is possible even
without hospitalization. The advancement of sensing technologies,
embedded systems, wireless communication technologies, nano
technologies, and miniaturization makes it possible to develop
smart systems to monitor activities of human beings continuously.
Wearable sensors detect abnormal and/or unforeseen situations
by monitoring physiological parameters along with other
symptoms. Therefore, necessary help can be provided in times
of dire need. This paper reviews the latest reported systems on
activity monitoring of humans based on wearable sensors and
issues to be addressed to tackle the challenges.