Self-control of interbeat interval and pulse transit time at rest and during exercise. A preliminary report

Attempts were made to establish self-control of interbeat interval (IBI) and pulse transit time (PTT) by providing appropriate biofeedback information to volunteers at rest and during dynamic and isometric exercise. Product feedback (IBI X PTT) was found more reliable than simple heart rate (HR) and systolic blood pressure (SBP) during dynamic exercise. It also produced greater increases in IBI and PTT than did habituation or relaxation under the same conditions. Product feedback was also superior to the use of other techniques at rest, but PTT feedback did not produce significant control of pressor responses during isometric exercise. Possible reasons for this failure are discussed. Preliminary results of feedback training given to 7 anginal patients suggest that such procedures might help to lower nitroglycerin consumption, decrease the frequency of anginal attacks and increase exercise tolerance.