Active Warm-up And Six- minute Walk Test Distance In Patients With Peripheral Arterial Disease

Peripheral arterial disease (PAD) leads to an accelerated decline in functional capacity and disability, and patients with PAD have a high risk of morbidity and mortality. At least one study has shown that passive heating improves six-minute walk test (6MWT) distance in patients with PAD. It is unknown whether an active walking warm-up can also increase 6MWT distance, and ultimately training performance, in patients with PAD. PURPOSE: The purpose of this study was to test the hypothesis that an active walking warm-up increases the six-minute walk test distance in patients with PAD. METHODS: In a block-randomized crossover design, fifteen patients with PAD (10 males, 5 females, ages 69-85 y, resting ankle-brachial index 0.66 + 0.04 or resting tibial-brachial index 0.31 + 0.50) completed two separate 6MWTs that were separated by 2-3 days. One 6MWT was preceded by an active warm-up of 10-12 minutes of walking on a treadmill (WARM-UP) at a workload between 1.4-2.1 METs and the other 6MWT was completed without a warm-up (CONTROL). The 6MWTs were completed on a 100 ft out and back course. The primary outcome measures were total walking distance, claudication onset distance and claudication onset time. Results are reported as means +95% confidence intervals. RESULTS: Total walking distance did not differ between the two study conditions (WARM-UP 302 + 17 m vs CONTROL 309 + 16 m, p = 0.333). Claudication onset distance did not differ between the two study conditions (WARM-UP 147 + 29 m vs CONTROL 124 + 16 m, p = 0.203). Claudication onset time did not differ between the two study conditions (WARM-UP 158 + 20 s vs CONTROL 141 + 17 s, p = 0.303). However, there was a trend (p = 0.053) toward a greater total walking distance on the second 6MWT (313 + 18 m) versus the first 6MWT (298 + 15 m), regardless of condition. CONCLUSIONS: The results of this study suggest that an active warm-up of 10-12 minutes of walking on a treadmill at a workload between 1.4-2.1 METs may not be enough of a stimulus to increase 6MWT distance in patients with PAD. Further, learning effects should be considered when designing protocols that utilize the 6MWT.