A reaction system comprising (a) a polyisocyanate component and (b) an isocyanate reactive component for preparation of a polyurethane foam having high air flow with low compression set is provided. The isocyanate reactive component comprises (i) from 45 to 70% by weight of one or more PO-rich polyols having a combined number average equivalent weight from 210 to 510, (ii) from 20 to 30% by weight of one or more ethylene oxide polyols having a combined number average equivalent weight from 200 to 500, (iii) from 10 to 25% by weight of one or more ethylene oxide-alkylene oxide polyethers having a combined number average equivalent weight from 300 to 800; and (iv) from 0.5 to 15% by weight of one or more PO-rich polyols having a functionality of 1 to 4 and a combined number average equivalent weight of 2,000 to 6,000.