One way to consider is to use the ... symbol to put your code in multiple lines. M-editor has a right-hand text limit, which is 75 characters by default and it has a line to indicate it.
VO2_Dyn_for_C=Value_C(eW_ore)*Coeff_C(eW_ore) ... +Value_C(ePCO_estimate)*Coeff_C(ePCO_estimate)