A comparison between the effects of dynamic and isometric exercise as evaluated by the systolic time intervals in normal man

Recovery from exercise at varying work loads. Time course of responses of heart rate and systolic intervals.

“…The striking similarity between pre-ejection period and isovolumic contraction time curves, while preisovolumic period changed minimally by comparison, indicates that changes in recovery pre-ejection period, like those of exercise pre-ejection period, were accounted for almost entirely by isovolumic contraction time. The exercise isovolumic contraction time (hence, preejection period) changes are consistent with the normal physiological response of sympathetically induced increased contractile velocity during exercise (Braunwald et al, 1958;Morehouse and Miller, 1963;Lindquist et al, 1973). Some of the exercise change may also be ascribed to increased preload resulting from the Starling effect associated with the early phase of upright exercise (Stafford et al, 1970;Spodick and Quarry-Pigott, 1973).…”

“…The uniform response patterns and the directional results, which parallel their invasively measured physiological correlates (Lindquist et al, 1973;Lance and Spodick, 1975), showed that these non-invasive techniques were an appropriate means for determining cardiac responses during actual exercise performance. Various invasive techniques, both in anaesthetised animals and in human subjects, have shown that the heart rate, blood pressure, stroke volume, left ventricular end-diastolic volume (LVEDV), sympathetic activity, and other variables change rapidly immediately after stopping exercise.…”

“…Changes in pre-ejection period were determined by changes in isovolumic contraction time; the degree of return toward control of pre-ejection period and isovolumic contraction time from their exercise nadirs was load-dependent throughout recovery; loaddependent differences in their rate of return were pronounced in thefirst 30 seconds. The rates of change in the ejection time index and in the ratio pre-ejection period/left ventricular ejection time (PEPILVET) were virtually independent of load throughout most of recovery.Polygraphic recording of systolic time intervals (STI) has been successfully applied during upright exercise (Miller et al, 1970;Pigott et al, 1971;Lindquist et al, 1973;Lance and Spodick, 1975;Xenakis et al, 1975). The uniform response patterns and the directional results, which parallel their invasively measured physiological correlates (Lindquist et al, 1973;Lance and Spodick, 1975), showed that these non-invasive techniques were an appropriate means for determining cardiac responses during actual exercise performance.…”

“…Polygraphic recording of systolic time intervals (STI) has been successfully applied during upright exercise (Miller et al, 1970;Pigott et al, 1971;Lindquist et al, 1973;Lance and Spodick, 1975;Xenakis et al, 1975). The uniform response patterns and the directional results, which parallel their invasively measured physiological correlates (Lindquist et al, 1973;Lance and Spodick, 1975), showed that these non-invasive techniques were an appropriate means for determining cardiac responses during actual exercise performance.…”

Sample Entropy and Traditional Measures of Heart Rate Dynamics Reveal Different Modes of Cardiovascular Control During Low Intensity Exercise

“…Currently, there are only few studies available that compared the cardiovascular response pattern to different exercise modes at similar HR. Lindquist et al found a stronger increase of systolic (SBP) and diastolic arterial blood pressure (DBP) during isometric handgrip compared to cycling at comparable HR of 90 bpm [23]. Leicht and his associates compared the cardiovascular response to dynamic muscular activity of different muscle groups at 50% maximum HR (HRmax) and 65% HRmax, respectively.…”