Ischemic preconditioning prevents impact of prolonged sitting on glucose tolerance and markers of cardiovascular health but not cerebrovascular responses

Abstract

Prolonged, uninterrupted sitting is demonstrated to acutely impair glucose homeostasis, but it also leads to detrimental cardiovascular health effects. We examined whether ischemic preconditioning (IPC) prevents the impact of prolonged sitting-induced glucose intolerance and measured related influencing factors such as (para)sympathetic nerve activity [assessed by heart rate variability (HRV)] and blood pressure during 2 h of prolonged sitting. In this randomized, controlled crossover study, 15 healthy participants (80% men) with a mean age of 21 ± 1 yr (means ± SD) and body mass index of 25.0 ± 2.4 kg/m2 performed IPC (IPC, 4 × 5-min 220-mmHg unilateral occlusion at the thigh muscle) or a sham intervention (sham, 4 × 5 min 20-mmHg), followed by 2 h of sitting. After IPC or sham intervention, fingertip blood glucose was measured before and after 30, 60, 90, and 120 min of 75 g of glucose ingestions. Blood glucose responses during an oral glucose tolerance test were significantly attenuated, resulting in a lower area under the curve when sitting was preceded by a bout of IPC than sham ( P < 0.05). IPC increased high-frequency oscillations and decreased the ratio of low-frequency-to-high-frequency oscillations at 120 min in HRV ( P < 0.05). Moreover, a lower blood pressure was observed with IPC compared with sham ( P < 0.05). Prolonged sitting or IPC did not affect cerebrovascular responses ( P > 0.05). Collectively, these results indicate that the application of IPC before prolonged, uninterrupted sitting bout was associated with a better glucose tolerance and prevented impairment in (para)sympathetic nerve activity and blood pressure in healthy young men and women.