Length of Cardiac Cycle and QT Interval During Exercise and Recovery in Athletes and Nonathletes

SummaryElectrocardiograms obtained during exercise on a treadmill and on a bicycle ergometer have shown that the relation between the QT and RR intervals can be represented by the equation QT = K+ 0.5 RR when K has a value of 70 msec. This equation was the same in trained and untrained subjects. During recovery from exercise the RR intervals lengthened much faster than the QT intervals.The alveolar pCO2 increased during the exercise while QT shortened. Immediately after exercise the alveolar pCO2 continued to increase at a time when the QT was no longer shortening.