Wearable technology can track your steps, analyze your sleep, measure your heart rate, and even tell you when to drink more water or take a breath when you are stressed. But can we trust our smart watch, glasses, or jewelry to tell us the truth about our health?

Health apps can be useful for those wishing to review their daily activities and make healthy lifestyle changes. Wearables are fun, and can increase productivity and efficiency at work and during workouts. They can even lead to better sleep and improved safety.

Smart tech can be especially useful to cardiologists and other physicians if they help to persuade a patient to make an appointment if they are experiencing symptoms of heart disease, such as chest, arm, or jaw pain; shortness of breath; cold sweats; and/or nausea, says Dr. Raval. She cautions, however, that wearables are not meant for diagnoses.

"Do not rely on your wearable technology to make a diagnosis; you will need bloodwork to learn your cholesterol levels, a blood pressure monitor to gauge your rates, and a pulse oximeter to measure your blood oxygen level," she notes.

Knowing your true numbers is essential to monitoring your health. These can be obtained during a yearly physical exam with your physician and through blood tests. Everyone should strive for these four optimal "numbers":

• Blood pressure: 120/80 or less
• Total blood cholesterol level: 200 or less
• Fasting blood glucose level: 100 or less
• Body mass index (BMI): between 18.5 and 24.9

Elevations in blood pressure, cholesterol, and blood glucose have few, if any, symptoms at first. The only way to know your levels is to have them measured by your physician regularly. Talk to your doctor about health screenings you need, especially if you have a family history of heart, disease, stroke, or diabetes, says Dr. Raval.

"The American Heart Association recommends that you begin heart health screenings at age 20, and repeat every four to six years," she concludes. "If you have a family history of cardiovascular disease, or other specific risk factors, your doctor may recommend more frequent screenings."

The bottom line: wearables are fun and useful for counting steps and making healthier lifestyle choices. But they don't compare to a relationship with your physician, routine exams and bloodwork.