{'fraction_non_alphanumeric': 0.05131337813072694, 'fraction_numerical': 0.03909590714722053, 'mean_word_length': 5.228136882129277, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Prolonged Sitting Impairs Forearm and Lower Leg Microvascular Reactivity

Previous studies examining the effects of sitting on vascular function have focused on flow‐mediated dilation of conduit arteries. However, whether prolonged sitting affects the reactivity of the microvasculature is largely unknown. Likewise, previous studies have focused on leg vascular responses; whether sitting alters vascular reactivity in the arms also remains unknown. In 8 young healthy men, lower‐leg (popliteal artery) and forearm (brachial artery) reactive hyperemia responses to 5‐min of limb occlusion were assessed at baseline and following 6 hours of uninterrupted sitting. Popliteal artery blood flow (BF) area under the curve (AUC) during reactive hyperemia was markedly reduced after 6 hours of sitting (BF, Baseline: 74650.85 A.U.; Post Sitting: 29745.67 A.U.; p<0.05). Interestingly, reactive hyperemia was also reduced in the forearm post sitting (BF, Baseline: 69523.06 A.U.; Post Sitting: 38996.12 A.U.; p<0.05). Next, since previous studies have demonstrated that physical activity can favorably impact microvascular function, we examined whether 10 minutes of walking (~1,000 steps) could improve microvascular reactivity following sitting. Reactive hyperemia in the lower leg (BF, Post Walking: 79630.49 A.U.; p>0.05 vs. Baseline) but not the forearm (BF, Post Walking: 44478.05 A.U.; p<0.05 vs. Baseline) was restored after walking. Collectively, these data suggest that prolonged sitting markedly reduces forearm and lower leg microvascular reactivity but only leg vascular responsiveness can be restored with a short bout of walking.