The arithmetic operators aren't defined for table or timetable arrays, in part because they often contain data for which those arithmetic operators don't really make sense.
patients = table(LastName,Gender,Age,Height,Weight,Smoker,Systolic,Diastolic);
What should the variable LastName in patients2 in the example below contain? How about the variable Smoker?
As Jon and KALYAN ACHARJYA said, you can operate on the variables in a table. One thing their posts did not show is that you don't have to store the results to a temporary variable then put them into a table. You can stick them directly back into the table.
patients.AgeNextYear = patients.Age + 1;
patients.WeightKG = patients.Weight/2.205;
patients.HeightM = patients.Height/39.37;
patients.BMI = patients.WeightKG./(patients.HeightM).^2;
patients2 = patients(:, ["LastName", "Age", "AgeNextYear", "HeightM", "WeightKG", "BMI"]);