|Isn't HIIT for everyone? Study suggests: Effective- and usefulness of high intensity interval training depend on age and fitness level.|
Good! Accordingly, you are not surprised that researchers from tie California State University San Marcos and the Griffith University at the Gold Coast in Queensland, Australia, teamed up to identify individual HIIT-responders and HIIT-non-responders.
The idea was to test whether there would be common denominators in those who do and those who don't respond with improvements in VO2max and lipid oxidation, as well as heart function and heart rate two commonly used modalities of interval training which have been previously-employed in the scientists lab.
"It was hypothesized that frequency of ‘‘non-responders’’ would be less than that typically reported after endurance training" (Astorino. 2014)The ultimate goal obviously is the development of individualized exercise prescription which may help optimize responses to training and overall health status of various individuals.
In this particular case this meant determining whether the 20 habitually-active men and women who participated in part 1 of the study would show inter-individual as well as inter-group differences compared to the 20 non-obese sedentary women from part 2 of the study.
- In study 1, recreationally-active men and women underwent 2 wk of Wingate-based standardized interval treatment. At baseline and after completion of training, measures of VO2max, HR, and lipid oxidation were determined on separate days at least 24 h apart. Participants were required to maintain their habitual training status which was confirmed with a training log, and time of day was standardized within subjects across all trials.
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|Figure 1: Changes in HR and fat oxidation in trained (left, part 1) & untrained (right, part 2) individuals (Astorino. 2014)|
"Frequency of improved fat oxidation was similar (60–65%) across regimens. Only one participant across both interventions showed nonresponse for all variables." (Astorino. 2014)Interestingly, the vaseline values of VO2 max, exercise HR, respiratory exchange ratio, and body fat were significant predictors of adaptations to interval training:
- Positive predictors of increases in VO2max were low baseline fitness (difficult to improve what's already top) and high effort during the wingate test.
- Positive predictors of improved heart rate was a high age and a high baseline heart rate
- Positive predictors of increases in fat oxidation were a low baseline physical activity and a low age.
- Astorino TA, Schubert MM (2014) Individual Responses to Completion of Short-Term and Chronic Interval Training: A Retrospective Study. PLoS ONE 9(5): e97638.