Heart rate of long distance runners

The data presents changes in the circulatory system of long distance runners before and just after extreme physical effort. In order to achieve that a group of voluntaries from the Sport Centre of the University of Physical Education and Sport in Gdansk had joined the research programme. They were obligated to take part in regular measurements of their heart rate just after the effort, as well as 24 and 48 hours after.The long distance run covered 100 km on a 3375 m loop with the total altitude difference not greater than 2 m. The run started at 7:20 in the morning and lasted for approximately 10 hours. The weather conditions during the run as follows: air temperature 4--5 degrees C, relative air humidity 86% with no wind. The heart rate of all voluntaries measured before the run was around 64--72/min, while just after the run was around 141--158/min.The heart rate of the runners was measured continuously from 12 minutes and thanks to that 450 sample long time series were collected. All heart rate signals were recorded based on the time intervals between successive R-waves of electrocardiographic signals.<br>The data is ordered according to the participants, i.e. each file 1.dat to 13.dat represents a single participant and his measurements gathered during the study. The column "day" indicates the day of the examination. The 1st day of examination took place on 16.11.2012 (one day preceding the extreme physical effort), the 2nd on 17.11.2012 (the day of the effort), the 3rd on 18.11.2012 (one day following the effort), the 4th on 19.11.2012 (two days following the effort). The column "timestamp" indicates the precise time of the examination (hh:mm:ss.sss), whereas the column "HR" contains the heart rate measurements in 1/min.