This is the first part of a multivariate data set recorded from a patient in the sleep laboratory of the Beth Israel Hospital in Boston, Massachusetts (data submitted by David Rigney and Ary Goldberger). The lines in the original data set file are spaced by 0.5 seconds. The first column is the heart rate, the second is the chest volume (respiration force), and the third is the blood oxygen concentration (measured by ear oximetry). The heart rate was determined by measuring the time between the QRS complexes in the electrocardiogram, taking the inverse, and then converting this to an evenly sampled record by interpolation. There were no premature beats - sudden changes in the heart rate are not artifacts. The respiration and blood oxygen data are given in uncalibrated A/D bits; these two sensors slowly drift with time (and are therefore occasionally rescaled by a technician) and can be detached by the motion of the patient, hence their calibration is not constant over the data set. They were converted from 250 Hz to 2 Hz data by averaging over a 0.08 second window at the times of the heart rate samples. Between roughly 4 hours 30 minutes and 4 hours 34 minutes from the start of the file the sensors were disconnected.