Effect Of Interval Versus Continuous Training On Measures Of Health-related Fitness

Abstract

Continuous training (CT) is used frequently by individuals to improve a variety of health-related fitness parameters including aerobic fitness, resting blood pressure and resting heart rate. Less research has been conducted however on the effect of interval training (IT) on these same health-related fitness measures. PURPOSE The purpose of this study was to compare the effect of interval versus continuous training on absolute and relative VO2max, resting systolic (SBP) and diastolic blood pressure (DBP), and resting heart rate (RHR). METHODS Forty-two volunteers were randomly assigned to an IT group (n=20) or a CT group (n=22). A separate control group (n=18) was formed from volunteers who were currently not engaged in CT or IT. Both training groups trained an average of 3 times per week for ten weeks starting the first week at 70% of VO2max for 30 min, increasing to 75% VO2max for 35 min the fifth week, and increasing to 80% VO2max for 40 min the eight week. The CT group maintained a constant intensity throughout the training session. The IT group completed a similar volume of work but varied the intensity within each session from 120–150% VO2max during the work intervals to 30–40% VO2max during the relief intervals. The training program was preceded and followed by a series of tests of VO2max, SBP, DBP and RHR. RESULTS The IT and CT groups improved significantly (p<.01) on both absolute and relative VO2max compared to the controls, with the IT group improving significantly better on relative VO2max than the CT group. Both training groups showed significant pre-post changes in percent fat and fat weight, but neither group changed significantly in comparison with the controls. SBP and DBP was reduced in the IT group, but not significantly compared to the CT group or controls. RHR was significantly lower in both training groups when compared with controls, but no difference was observed between the training groups. CONCLUSIONS The results of the study indicate that IT increased relative VO2max not only as well as CT, but actually better than CT. No differences were observed between IT and CT with regard to body composition or resting blood pressure. Similar reductions in RHR were observed in both training groups. Interval training, it appears, can be recommended in lower risk adults as an alternative to continuous training, resulting in significant improvements in aerobic fitness with no detrimental effects on resting blood pressure.