Walking Economy is Impaired in Older Men and Women with Type 2 Diabetes

Objective: We compared the walking economy in older participants with and without type 2 diabetes. Methods: Walking economy was determined in 115 older participants with type 2 diabetes and 130 older control participants without diabetes by continuously measuring oxygen uptake during a treadmill test in which the work rate was at a constant speed of 2 mph and a grade of 0% for a duration of 10 minutes. Participants also completed a Balke treadmill protocol for the determination of peak oxygen uptake, defined as the highest oxygen uptake value attained during the final work stage attained. Fractional utilization was then calculated as the walking economy oxygen uptake divided by peak oxygen uptake, expressed as a percentage. Results: Compared to those without diabetes, participants with type 2 diabetes were older (p=0.042), had higher prevalence of men (p=0.034), obesity (p=0.010), chronic kidney disease (p=0.020), peripheral artery disease (p=0.024), and had a higher body mass index (p=0.025), and waist/hip ratio (p=0.006). After adjusting for these variables, the participants with diabetes had higher walking economy (p<0.001), fractional utilization (p<0.001), and lower peak oxygen uptake (p<0.001) than those without diabetes (p<0.001). Conclusions: Older men and women with type 2 diabetes are less economical when they ambulate at a given speed than compared to control participants without diabetes, independent of their greater co-morbid burden. The impaired walking economy in the diabetic participants is further magnified by their lower aerobic fitness, thereby leading to a higher fractional utilization of oxygen consumed during a given walking task.