The impact of artifacts on estimates of heart period
variability were evaluated by modeling the effects of missed
R-waves and spurious R-wave detections in actual and simulated
heart period series. Results revealed that even a single
artifact, occurring within a 128-s interbeat interval series,
can impart substantial spurious variance into all commonly
analyzed frequency bands, including that associated with
respiratory sinus arrhythmia. In fact, the spurious variance
introduced by a single artifact may be greater than that
associated with true basal heart period variability and
can far exceed typical effect sizes in psychophysiological
studies. The effects of artifacts are not related to a
specific analytical method and are apparent in both frequency
and time domain analyses. Results emphasize the importance
of artifact detection and resolution for studies of heart
period variability.