The influence of moderate- and high-intensity exercise on perception of exercise intensity and physiological variables during self-selected aerobic exercise

Abstract

Basing exercise prescriptions on self-selected exercise intensity (SS exercise intensity) has become increasingly popular among exercise professionals. However, because individuals tend to select a low intensity at which to exercise, it is unknown whether exercising at a self-selected intensity provides sufficient health benefits for most of the population. It may be more efficacious to prescribe predetermined loads in combination with SS exercise intensity. To evaluate this premise, this study compared the level of SS exercise intensity following brief sessions of moderate- or high-intensity exercise. Three exercise trials of 20 min were compared in 8 healthy men, aged 24.6±1.8 years. During the first trial (baseline), the subjects performed 20 min of cycling at a SS exercise intensity. The other two trials consisted of 5 min fixed-load cycling at 50% (moderate intensity) or 70% (high intensity) of maximal oxygen uptake (SSFL_<50%> and SSFL_<70%>) followed by 15 min cycling at a SS exercise intensity. The SS exercise intensity (Watts) was higher immediately after both moderate and/or high fixed load exercise bouts compared to the baseline SS trial. However, the ratings of perceived exertion (RPE) during SSFL_<50%> were similar to the responses during the baseline SS trial. These data suggest that exercising at a moderate and/or high fixed load prior to exercising at a SS exercise intensity will increase the intensity of exercise. Therefore, it is recommended that prescriptions for aerobic exercise include a combination of fixed load and SS exercise intensity.