Cardiovascular response and cost of downhill walking: a novel exercise modality for people with type 2 diabetes mellitus (t2dm)

INTRODUCTION & AIMS Exercise is a cornerstone in managing T2DM, along with diet and medication. Walking is the easiest to perform and most widely recommended exercise for people with T2DM. However, people with T2DM appear to walk 1200 to 2500 less steps per day than healthy people as many find exercise or walking to be exhausting. Downhill walking may be an alternative to conventional exercise for people with T2DM. Little is known about the metabolic cost of incline walking in people with T2DM. This study determined the energy cost of walking downhill, uphill, and on a flat level surface in people with T2DM. METHODS Participants walked on a treadmill at 2.5 km/hr, starting at 0% grade for 4 minutes and progressing to 4%, 8%, 12%, and 16% for four minutes at each grade. After resting for 10 minutes, they walked downhill at -4%, -8%, -12%, and -16% grades. Borg’s 6-20 RPE scale measured perceived exertion, while VO2, pulmonary ventilation, and energy expenditure were measured using an automated gas analysis system. Expired gas was collected every 15 seconds, and the average of the four readings of the fourth minute of walking at each grade was used for analysis. RESULTS Compared to flat-level the 4%, 8%, 12% and 16% incline increased energy cost by 17.5%, 42.6%, 68.3% and 95.1% respectively. Compared to level walking, walking at -4%, -8%, -12% and -16% treadmill decline decreased the metabolic energy cost by 13.1%, 15.2%, 17.9% and 13.4% respectively. Similarly, cardiometabolic response (HR) and perceived effort during downhill walking were lower than walking uphill. CONCLUSION Health professionals wanting to promote exercise as part of a lifestyle approach to manage T2DM could consider downhill walking as an exercise option as it induces lower cardiovascular and metabolic responses and is perceived as easier than uphill walking.