A coated viscoelastic polyurethane foam, comprising: a viscoelastic polyurethane foam having the coating thereon, the viscoelastic polyurethane foam having a resiliency of less than or equal to 20 % as measured according to ASTM D3574, the viscoelastic polyurethane foam being the product of a reaction system having an isocyanate component that includes at least one isocyanate and an isocyanate-reactive component that includes a polyol component, and an isocyanate index of the reaction system being from 50 to 150; and a coating material on and embedded within the viscoelastic polyurethane foam, the coating material including an aqueous polymer emulsion and an encapsulated phase change material; wherein the reaction system further includes an additive component that includes at least one catalyst and at least one selected from the group of: (i) 0.1 wt% to 6.0 wt% of a preformed aqueous polymer dispersion, based on the total weight of the mixture, the preformed aqueous polymer dispersion having a solids content from 10 wt% to 80 wt%, based on the total weight of the preformed aqueous polymer dispersion, and being one of an aqueous acid polymer dispersion or an aqueous acid-modified polyolefin polymer dispersion in which the polyolefin is derived from at least one C 2 to C 20 alpha-olefin, and (ii) from 0.1 wt% to 6.0 wt% of a preformed aqueous polymer dispersant having a pH from 6.0 to 12.0, based on the total weight of the mixture, the aqueous polymer dispersant including from 5 wt% to 60 wt% of a polymeric component and from 40 wt% to 95 wt% of a fluid medium that includes at least water, the polymeric component including at least one base polymer derived from 20 wt% to 100 wt% of at least one hydrophilic acid monomer having at least one carbonyl group, phosphate group, phosphonate group, or sulfonyl group, and optionally derived from at least one hydrophobic terminally unsaturated hydrocarbon monomer. a viscoelastic polyurethane foam having the coating thereon, the viscoelastic polyurethane foam having a resiliency of less than or equal to 20 % as measured according to ASTM D3574, the viscoelastic polyurethane foam being the product of a reaction system having an isocyanate component that includes at least one isocyanate and an isocyanate-reactive component that includes a polyol component, and an isocyanate index of the reaction system being from 50 to 150; and a coating material on and embedded within the viscoelastic polyurethane foam, the coating material including an aqueous polymer emulsion and an encapsulated phase change material; wherein the reaction system further includes an additive component that includes at least one catalyst and at least one selected from the group of: (i) 0.1 wt% to 6.0 wt% of a preformed aqueous polymer dispersion, based on the total weight of the mixture, the preformed aqueous polymer dispersion having a solids content from 10 wt% to 80 wt%, based on the total weight of the preformed aqueous polymer dispersion, and being one of an aqueous acid polymer dispersion or an aqueous acid-modified polyolefin polymer dispersion in which the polyolefin is derived from at least one C 2 to C 20 alpha-olefin, and (ii) from 0.1 wt% to 6.0 wt% of a preformed aqueous polymer dispersant having a pH from 6.0 to 12.0, based on the total weight of the mixture, the aqueous polymer dispersant including from 5 wt% to 60 wt% of a polymeric component and from 40 wt% to 95 wt% of a fluid medium that includes at least water, the polymeric component including at least one base polymer derived from 20 wt% to 100 wt% of at least one hydrophilic acid monomer having at least one carbonyl group, phosphate group, phosphonate group, or sulfonyl group, and optionally derived from at least one hydrophobic terminally unsaturated hydrocarbon monomer. (i) 0.1 wt% to 6.0 wt% of a preformed aqueous polymer dispersion, based on the total weight of the mixture, the preformed aqueous polymer dispersion having a solids content from 10 wt% to 80 wt%, based on the total weight of the preformed aqueous polymer dispersion, and being one of an aqueous acid polymer dispersion or an aqueous acid-modified polyolefin polymer dispersion in which the polyolefin is derived from at least one C 2 to C 20 alpha-olefin, and (ii) from 0.1 wt% to 6.0 wt% of a preformed aqueous polymer dispersant having a pH from 6.0 to 12.0, based on the total weight of the mixture, the aqueous polymer dispersant including from 5 wt% to 60 wt% of a polymeric component and from 40 wt% to 95 wt% of a fluid medium that includes at least water, the polymeric component including at least one base polymer derived from 20 wt% to 100 wt% of at least one hydrophilic acid monomer having at least one carbonyl group, phosphate group, phosphonate group, or sulfonyl group, and optionally derived from at least one hydrophobic terminally unsaturated hydrocarbon monomer.