Abstract
BackgroundAfrican American (AA) women have a higher prevalence of obesity and related metabolic dysfunction and lower level of physical activity compared to white counterparts. Determining feasible exercise alternatives for AA women is, therefore, paramount. Time-efficient high-intensity interval training (HIIT) might be particularly suited for AA women who cite time constraints as a frequent barrier to exercise adherence. The purpose of this study was to assess the feasibility of a 14-week progressive HIIT protocol for previously-sedentary overweight/obese AA women.MethodsTwenty-eight healthy, premenopausal (age, 20–40 yr), sedentary, nondiabetic, overweight/obese AA women volunteered to participate in the randomized controlled clinical trial from which these data were retrospectively analysed. After assessment, participants were randomly allocated to a HIIT group (n = 14) or a no-exercise control group. The HIIT intervention consisted of 24-min sessions performed three times per week for 14 weeks during which work-interval intensity (75 to 90% of heart rate reserve; HRR) and duration (30 to 60 s) and work/recovery ratio (1:7 to 1:3) were progressed in four stages. Feasibility was assessed based on adherence (attrition rate), perceptual response (RPE) and success rate, which was calculated based on the degree to which target intensities for work intervals were achieved/maintained.ResultsFive of 14 participants (35%) in the HIIT group dropped out during the intervention. One-way repeated-measures ANOVA revealed a significant difference across stages for success rate (p = 0.018) with post-hoc analysis indicating a significant difference between stage 1 and the other stages and stage 4 and the other stages. There was no significant difference in RPE across stages (p = 0.057).ConclusionAlbeit based on a limited number of participants, we found an attrition rate that was higher than what has been reported previously for HIIT (~ 17.6%) when previously-sedentary overweight/obese AA women performed a protocol with work-interval intensity progressed from 75 to 90% HRR during a 14-week intervention. With respect to intensity, the precipitous drop for achievement of the target HR during the fourth stage (weeks 8–14) for those who did complete the protocol implies that it might be advisable to restrict work-interval intensity to < 90% HRR.Trial registrationClinicalTrials.gov. (NCT04293367). Registered 03 March 2020 – Retrospectively registered.
Highlights
African American (AA) women have a higher prevalence of obesity and related metabolic dysfunction and lower level of physical activity compared to white counterparts
Albeit based on a limited number of participants, we found an attrition rate that was higher than what has been reported previously for high-intensity interval training (HIIT) (~ 17.6%) when previously-sedentary overweight/obese AA women performed a protocol with work-interval intensity progressed from 75 to 90% heart-rate reserve (HRR) during a 14-week intervention
The other participant who dropped out during the initial two stages of training did so citing an inability to satisfy the time commitment associated with attending the exercise sessions and both of the other dropouts occurred for the same reason: one during week 7 and one during week 11
Summary
African American (AA) women have a higher prevalence of obesity and related metabolic dysfunction and lower level of physical activity compared to white counterparts. This study involved 3 weeks of supervised training followed by 5 weeks of unsupervised training during which adherence did not decrease for either group [8] This refutes speculation by Lunt et al that the physiological adaptations induced by HIIT in the laboratory setting might not reflect what can be achieved in the real world where dropout is more likely [7]. The reason(s) for this lack of coherence regarding how well HIIT is physically and/or psychologically tolerated by individuals unaccustomed to exercise is unclear, but might represent different HIIT protocols that were investigated and/or different populations that were studied With respect to the former, variables that might be important to consider are the intensity at which HIIT work intervals are performed and the volume of the HIIT protocol [12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
