Affective Responses to Exercise are Dependent on Intensity rather than Total Work.
Medicine & Science in Sports & Exercise. 39(8):1417-1422, August 2007. Kilpatrick, Marcus ; Kraemer, Robert ; Bartholomew, John ; Acevedo, Edmund ; Jarreau, Denise.
Purpose: The purpose of the study was to compare affective(emotional) responses for two bouts of cycle ergometry with differing duration and intensity, but equal total work in kilocalories.
Method: Thirty-seven participants (20 male, 17 female, mean age 23.9 yr) completed a multistage cycle ergometer protocol to determine ventilatory threshold (VT) and peak oxygen consumption (mean = 34.9 mLxkg-1xmin-1). Two cycling trials were prescribed: 30 min at 85% of VT (50.1% VO2 reserve) and an average of 24 min at 105% of VT (64.7% VO2 reserve). The length of the 105% of VT bout was adjusted to yield equal total work in each exercise trial.
Results: Using repeated-measures ANOVA, heart rate and exertion were significantly higher, and affective valence was significantly less positive (P < 0.01) for the higher-intensity, shorter-duration bout, with no differences in felt arousal (P > 0.05). Additionally, affective valence became less positive during the higher-intensity bout (P < 0.01) but not the lower-intensity bout (P > 0.05).
Conclusion: This data expand on previous findings by showing that the decline in ratings of pleasure during higher-intensity exercise is not dependent on differences in total caloric expenditure. Additionally, results from this study support continued promotion of prescriptions that focus on exercise intensity that does not exceed the ventilatory threshold.
Slow and Steady wins the Race!
Practically speaking, the results of this study indicate that exercise at a comfortable rate will likely result in more enjoyment and better adherence with a program than would a program at a higher intensity. Since everyone can not assess their VT (ventilatory threshold), work/exercise at a level that allows you to talk while working out or use the following calculation:
Estimate Your MAXIMUM Heart Rate To Get Your Best Workout Heart Rate:
220 - your age = 100%
(220 - your age) x 0.8 = 80%
(220 - your age) x 0.5 = 50%
Generally it is recommended that you keep your heart rate between 50% to 80% of your maximum heart rate for safety while you exercise. Keeping in mind the previous research study, try to keep your heart rate between 50% to 65% to help you stick to the program and gain more enjoyment from your workout. As an added bonus, less aggressive workouts put less stress on your heart, lungs, and joints. Remember that walking 3 km versus running 3km use up the same calories and result in the same weight loss but there is no weight lost if you quit the program so BE SURE TO ENJOY YOURSELF WHATEVER YOU DO!
A few high blood pressure medications lower the maximum heart rate and thus the target zone rate. If you're taking such medicine, call your physician to find out if you need to use a lower target heart rate. This calculation only gives you an average and should only be used as a guideline. Always check with a health professional before
starting a new exercise program.
Article by Don Sorensen BSC.P.T., A.T. Dip C.A.F.C.I
Registered Physiotherapist & Owner of Body 'N Balance Physiotherapy
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