HEART RATE VARIABILITY IN RESPONSE TO BLOOD FLOW RESTRICTION TRAINING AND REDUCED SEDENTARY TIME: A PILOT STUDY
Tanya Miller, Clayton Nicks, Brian Tyo, Kate Early. Columbus State University, Columbus, GA.
BACKGROUND: Excessive sedentary time is associated with increased cardiovascular disease (CVD) risk. In sedentary middle-aged adults, resistance training has been found to improve comorbidities associated with CVD, such as heart rate variability (HRV). Few studies have examined the impact of blood flow restriction (BFR) training, a safe and effective alternative to traditional resistance training, on HRV. The purpose of this study was to examine the effects of 20 weeks of BFR training or reduction of SED in sedentary adults. METHODS: Campus office workers (n = 14, 36% male, age 29-66 y) underwent resting HRV, handgrip strength, and muscular endurance testing. Subjects were randomized to the following: BFR 3days/week consisting of 20-minute (60 sessions total), supervised sessions using Theraband; reduced sedentary time (SED) consisting of accumulated three 10-minute periods of standing during the work-day; and CON maintained normal activity. Time and frequency domain metrics of HRV were derived pre-, mid- and post-intervention. RESULTS: A repeated measures ANOVA revealed no changes in HRV within the control (n=6, p>0.05) or sedentary group (n=4, p>0.05). No significant changes were found in the BFR group (n=6, p>0.05), with the exception of heart rate, which changed pre- to mid-intervention (p=0.02). No significant changes were found in handgrip strength within the control (n=6, p>0.05) or sedentary group (n=4, p>0.05). Significant changes were found in the BFR group for right grip strength (n=6, p>0.05), which changed mid- to post-intervention (p=0.03). No significant changes were found in muscular endurance within the sedentary (n=4, p>0.05) or BFR group (n=6, p>0.05). No significant changes in muscular endurance were found within the control group (n=6, p>0.05), with the exception of knee flexor repetitions, which changed pre- to post-intervention (p=0.03).CONCLUSIONS: 20 weeks of BFR did not result in changes in HRV in sedentary adults. Changes were found in the BFR group for heart rate pre- to mid-intervention and right handgrip strength mid- to post-intervention, and in the control group for knee flexor repetitions, likely due to the familiarization effect. These results are expected given our sedentary but generally healthy population. Caution is warranted when interpreting practical applications of these preliminary results given our sample size.
Miller, T; Nicks, C; Tyo, B; and Early, K
"HEART RATE VARIABILITY IN RESPONSE TO BLOOD FLOW RESTRICTION TRAINING AND REDUCED SEDENTARY TIME: A PILOT STUDY,"
International Journal of Exercise Science: Conference Proceedings: Vol. 16:
1, Article 325.
Available at: https://digitalcommons.wku.edu/ijesab/vol16/iss1/325