Hemoglobin A1c levels measure long-term control of blood sugar levels, and are an even better indicator of heart disease risk than fasting glucose. Currently 7% is the accepted safe upper limit.
A study published in 2004 in the Annals of Internal Medicine shows a positive correlation between increasing Hg A1c levels and increased risk of death from cardiovascular disease. The study also suggests keeping A1c below 5% may be even better for your heart.
25 kg/m2 -- Body Mass Index (BMI)
Despite minor flaws (it cannot account for a higher than normal percentage of muscle mass), BMI provides a useful gauge for determining a heart-healthy weight. Keep your BMI just below 25.
35 inches (women) or 40 inches (men) -- Waist Circumference
Studies suggest that people with larger waists are more likely to develop heart disease.
Waist circumference is even more useful when used in conjunction with BMI, and The National Heart, Lung and Blood Institute has a chart where you can gauge your risk of developing obesity associated conditions, including heart disease, based on both numbers.
If you don't know your numbers, see your doctor for a checkup and blood tests. Once you know how your numbers compare to the ideal, formulate a plan to bring any out-of-range numbers back in line.