Physiological Responses During the Lower Body Positive Pressure Supported Treadmill Test

Area of Science:

• Cardiopulmonary physiology
• Exercise science
• Rehabilitation engineering

Background:

• Exercise tolerance testing (ETT) is crucial for assessing cardiopulmonary function.
• Patients with gait problems often face limitations in performing standard ETT.
• Lower body positive pressure support (LBPPS) offers a potential method to modify exercise intensity.

Purpose of the Study:

• To quantify cardiopulmonary function changes during LBPPS-supported ETT in healthy subjects.
• To establish a foundation for using LBPPS treadmills in patients with gait impairments.
• To assess the feasibility of submaximal ETT with LBPPS.

Main Methods:

• 30 healthy, independent walkers underwent ETT using the Modified Bruce Protocol.
• Four LBPPS levels (0%, 40%, 60%, 80%) were applied.
• Systolic blood pressure, diastolic blood pressure, peak heart rate (PHR), rating of perceived exertion (RPE), metabolic equivalents (METs), and oxygen consumption (VO2) were measured.

Main Results:

• Systolic blood pressure increased with higher LBPPS levels (40%-80%).
• PHR, RPE, METs, and VO2 showed negative associations with LBPPS, though not always statistically significant.
• A regression model predicted VO2 based on exercise stage and LBPPS level (r²=0.69).

Conclusions:

• LBPPS significantly influences physiological parameters during submaximal ETT.
• Monitoring these changes can inform LBPPS treadmill use in individuals with exercise limitations.
• The LBPPS system shows promise for enabling ETT in patients with gait deficits.