BACKGROUND: In cases of injury or illness, the ability to maintain physical activity and regular exercise decreases, which may reduce cardiovascular health and fitness. Blood flow restriction (BFR) has been shown to delay muscle atrophy during immobilization but does not appear to improve the vasculature when applied for 2-weeks. BFR is typically applied by inflating a cuff on the upper part of the limb and temporarily reducing blood flow. Prior to conducting a longer study, we want to determine if shortening the inflation time from 5 min to 3 min would improve perceptions during the protocol and/or effectiveness. The purpose of this study is to determine the discomfort and effectiveness of shorter inflations and more cycles than the current recommended BFR protocol. METHODS: Using a within-subject design, we will recruit 30 healthy male and female participants (18 - 35 years old) for this study. We will compare the cardiovascular response and perceptual response of a typical BFR protocol (BFR5) and a protocol that has more inflation cycles due to a shorter duration of inflation (BFR3). After informed consent and anthropometric measures, sensors and the BFR cuff will be secured to the dominant arm. Participants will rest supine for 5 min with their dominant arm 90 degrees from their side. Resting measures of heart rate, tissue saturation index (via near infrared spectroscopy), oxygen saturation (via pulse oximetry), and ratings of perceived discomfort will be collected in the last 30 seconds of cuff inflation. Each participant will complete 3 conditions (randomized and counterbalanced) with at least 48 hours between conditions. Arterial occlusion pressure (AOP) will be measured after resting measures. For the typical BFR condition (BFR5), there will be 5 cycles (5 min inflated/3 min deflated) at a cuff pressure of 80% AOP. For the altered BFR protocol (BFR3) there will be 7 cycles (3 min inflated/3 min deflated) at 80% AOP. During the control condition (CON) individuals will rest supine with an uninflated cuff (0% AOP). For our statistical analysis we plan to calculate three change scores (first cycle-rest; fifth cycle-rest; last cycle-rest) and compare these using a one-way Bayesian Repeated Measures ANOVA (JASP, 0.17.3). ANTICIPATED RESULTS: Shorter cuff inflations and additional cycles of BFR may have less discomfort and ischemia, but similar oxygen saturation and heart rate as the typical BFR protocol.

This document is currently not available here.