During strenuous exercise, lactic acid buildup in cells causes the creation of a hydronium complex known as the Eigen cation (H9O4+). If water molecules then experience hydrogen bond attractions to the Eigen cation, this attractive force:

Will result in a semi-stable shell of water molecules around the hydronium.

Explanation:

A procedure is known as hydration also called solvation takes place when the attractive force of the molecule of ion leads to the formation of a thin shell of water molecules to envelope it. In the case of H3O+, that is, hydronium, each of the hydrogen atoms attracts the atom of oxygen in the molecule of water because of hydrogen bonding. These molecules of water will result in a shell of water molecules to encircle the hydronium.