Heart rate time series for 5 different groups of healthy subjects can be found in text form in the subdirectories of this one:
A detailed description of these 5 groups can be found in the original article (reference below).
For each recording, in addition to the text file, there are (in this directory) a binary annotation file (with suffix .qrs) and a text header file (with suffix .hea), written in the standard formats used for other PhysioBank databases. Each set of three files has a common record name composed of a group identifier and a subject identifier (number). Although all beats are marked normal in these recordings, there may be small numbers of abnormal beats.
The text files contain the same information as in the annotation and header files, and may be reproduced from the annotation and header files using the program ihr, available here. The first column in each text file is the elapsed time since the beginning of the recording (in seconds), and the second column is the instantaneous heart rate (in beats/minute). Note that these recordings generally contain lengthy unannotated intervals preceding the first annotation.
Peng C-K, Mietus JE, Liu Y, Khalsa G, Douglas PS, Benson H, Goldberger AL. Exaggerated Heart Rate Oscillations During Two Meditation Techniques. International Journal of Cardiology 70:101-107, 1999.