FNDC5 and Stroke: Physical activity in stroke patients with low level of irisin (Q1) were lower compared with those in patients with normal irisin (Q2–4) [0.8 (IQR, 0.5–1.2) kcal/kg day vs. 1.5 (IQR, 1.0–1.9) kcal/kg day; P < 0.001].