The ideal LDL cholesterol level for a 30 year old man should be above 60 mg/dL and HDL level should be below 100 mg/dL, according to NIH MedlinePlus. Total cholesterol levels should be below 200 mg/dL.
Some uncontrollable factors that affect cholesterol levels are heredity, age, gender and family history, states NIH MedlinePlus. High blood cholesterol may run in families, and men and women produce more cholesterol as they age. Ceasing smoking, adopting a healthy diet and exercising (30 minutes of physical activity most days) play a role in controlling cholesterol levels. Eating a diet low in saturated fat and cholesterol can affect total levels.