The effects of respiratory muscle resistance training on lactate threshold: a potential effort to prevent muscle fatigue during exercise

Abstract

Respiratory muscle resistance training (RMRT) is the practice of breathing through a respiratory mouth-device designed to restrict airflow to the user, increase airway resistance and subsequently increase the work necessary for the respiratory muscles to inspire and expire. During periods of exercise, there is an elevation in blood lactate levels as well as H+, which is a major contributing factor to exercise fatigue. The resultant elevated plasma acidity is compensated by an increased ventilation rate, which leads to increased expiration and removal of carbon dioxide (CO2) from the body. It was hypothesized that healthy college students that undergo four weeks of RMRT exercise will have improved oxygen consumption at the point of lactate threshold (VO2LT) during a graded exercise running test. The experimental group used an Expand-a-Lung RMRT device 5 times a week and tested weekly for four weeks by using near-infrared spectroscopy (NIRS) with a BSX Insight blood oxygenation sensor to measure the amount of oxygen-saturated hemoglobin (%SmO2) in the calf muscle. Our preliminary results show some improvement in ventilation in the experimental group, with tidal volume significantly increasing the most. The VO2 at lactate threshold did show an increase, providing support for our original hypothesis.