Comparison of upper-limb and lower-limb exercise training in patients with intermittent claudication.

To investigate the effects of a 24-week programme of upper- and lower-limb aerobic exercise training on walking performance and quality of life in patients with symptomatic peripheral arterial disease (PAD) and to study the mechanisms, which could influence symptomatic improvement. Following approval from the North Sheffield Local Research Ethics Committee, 104 patients (median age 69 y, range 50-85 y) with stable PAD were randomised into an upper- or lower-limb aerobic exercise training group, or to a nonexercise training control group. Training was performed twice weekly for 24-weeks at equivalent relative exercise intensities. An incremental arm- and leg-crank test (ACT and LCT, respectively) to maximum exercise tolerance was performed before and at 6-, 12-, 18- and 24-weeks of the intervention to determine peak oxygen consumption (VO[2]). Walking performance, defined as the claudication and maximum walking distance (CD and MWD respectively) achieved before intolerable claudication pain, was assessed at the same time-points using a shuttle-walk protocol. Peak blood lactate concentration, ratings of perceived exertion (Borg RPE) and pain (Borg CR-10) were recorded during all assessments. Physical activity status, community-based walking ability and quality of life were assessed throughout the intervention period. Assessments were repeated 6-, 12-, 24- and 48-weeks following the intervention period. Both CD and MWD increased over time (P <0.01) in both training groups.At 24-weeks, CD had improved by 56% and 65% and MWD had improved by 30% and 35% (P <0.01) in the upper-limb and lower-limb exercise groups, respectively. These changes were associated with improvements in community-based walking distance, speed and stair-climbing ability (P <0.01). All patients assigned to exercise training exhibited an increase in LCT peak VO[2] at the 24-week time-point in relation to baseline measures (P <0.01) and control patients (P <0.01), whereas ACT peak VO[2] at the 24-week time-point was only improved in the upper-limb exercise training group (P <0.05). An increase in peak blood lactate concentration (1.95 +/- 0.14 vs. 2.40 +/-0.17 mM, mean +/- SEM; P <0.05) and amount of pain experienced at MWD (P <0.05) was only observed in the upper-limb exercise training group. This suggests that an alteration in exercise pain tolerance accounted, at least in part, for the improvement in MWD in this group. Upon completing the intervention period the general health status of both exercise training groups was improved in relation to the control group (P <0.05). However, improvements in physical functioning and bodily pain in relation to baseline (P <0.05) and energy and vitality in relation to control patients (P <0.05) were only observed in the upper-limb training group. At 48-weeks follow-up, CD remained improved by 39% and 48% (P <0.05) and MWD remained improved by 18% and 26%(P <0.05) in the upper-limb and lower-limb exercise groups, respectively, compared to baseline measures. A retained improvement in walking confidence (P <0.01) and community-based walking distance (P <0.05) was also observed, however global physical activity status in both exercise trained patient groups, returned to baseline. Both upper- and lower-limb aerobic exercise training can be useful exercise training modalities for improving cardiovascular function, walking performance, exercise pain tolerance and quality of life in patients with symptomatic PAD. This study suggests that a combination of physiological adaptations and altered exercise pain tolerance might account for the improvement in walking performance achieved through upper-limb aerobic exercise training in patients with PAD. This study also indicates that although walking performance remained improved in both exercise trained patients at 48-weeks follow-up, as compared to baseline measures, a progressive dwindling of improvement was observed over this time period. Reluctance for the continuation of exercise in the home-setting was observed.