Presently, cardiovascular issues have become an emerging challenge for physiologists and researchers. Due to the fact, that the population is growing at a rapid pace and of course there is a shortage of doctors and hospitals, the demand and cost of healthcare is rising and is a topic of major concern. Also, it is not always possible for the affected person to visit the hospital or the doctor. In addition to this, specifically talking about people suffering from cardiac diseases, they require a system which continuously monitors their heart activities so that instantaneous detection of cardiac abnormalities at an early stage can be performed, consequently followed by an immediate remedy/treatment by the doctor. As a result, a huge amount of attention has been diverted to make the health-care systems intelligent i.e., real-time, continuous, long-term sensing and monitoring of bio-signals which can be carried out even at remote locations whether the person is in motion or at rest. There are several methods to measure the bio-signals but Electrocardiogram (ECG) is the premium method for measuring the heart signals. In this paper, we review the domains where continuous and long-term supervision of heart-rate is essential; the areas include elderly and differently-abled people, fetal ECG monitoring, infant monitoring, monitoring for automobile drivers, etc.