Cardiovascular health isn’t a single number. It’s a composite picture built from several measurable factors: blood pressure, cholesterol, blood sugar, aerobic fitness, and markers of inflammation and arterial damage. Some of these you can track at home with a watch or a cuff. Others require a blood draw or a scan. Here’s what each measurement tells you and what numbers to aim for.
Blood Pressure: The Most Accessible Metric
Blood pressure is the easiest cardiovascular metric to check at home, and it’s one of the most important. The ideal reading is below 120/80 mmHg. The 2025 guidelines from the American Heart Association and American College of Cardiology now recommend a preferred target below 120/80 for most adults, tightening the previous goal of 130/80. Readings of 130/80 or above typically warrant medication if you have diabetes, kidney disease, or an elevated 10-year risk of a cardiovascular event. At 140/90 or above, treatment is recommended regardless of other risk factors.
If you’re measuring at home, sit quietly for five minutes first, keep your arm supported at heart level, and take two readings a minute apart. Morning readings before coffee or medication tend to be the most consistent. A single high reading doesn’t mean much. Patterns over days and weeks do.
Cholesterol and Blood Sugar
A standard lipid panel from a blood draw gives you total cholesterol, LDL, HDL, and triglycerides. Ideal total cholesterol is below 200 mg/dL without medication. For fasting blood glucose, the ideal threshold is below 100 mg/dL, also untreated. These are the benchmarks used in the AHA’s cardiovascular health framework.
Standard LDL cholesterol is the traditional target, but it has a blind spot. More than half of people who have heart attacks have LDL levels considered “normal,” and coronary events still occur in patients aggressively treated with statins. Two alternatives capture risk more accurately: non-HDL cholesterol (your total cholesterol minus HDL, which you can calculate from any standard panel) and apolipoprotein B (apoB), a direct count of the particles that drive plaque buildup. Both outperform LDL in predicting cardiovascular disease. ApoB requires a separate blood test and is still considered an add-on rather than a replacement, partly because doctors haven’t agreed on universal treatment targets for it. Non-HDL cholesterol, on the other hand, is free information already sitting on your lab results.
High-Sensitivity CRP
Inflammation inside your arteries accelerates plaque formation, and a blood test called high-sensitivity C-reactive protein (hs-CRP) measures it. The risk categories are straightforward: below 1 mg/L is low risk, 1 to 3 mg/L is moderate risk, and 3 mg/L or above is high risk. This test is most useful for people in an intermediate risk zone where traditional cholesterol numbers alone don’t tell the full story. Infection, injury, or autoimmune conditions can temporarily spike CRP, so an elevated result usually warrants a repeat test a few weeks later to confirm it reflects cardiovascular inflammation rather than something else.
Aerobic Fitness and VO2 Max
Your VO2 max, the maximum amount of oxygen your body can use during exercise, is one of the strongest predictors of cardiovascular health and longevity. People in the bottom 25% of fitness have twice the risk of cardiovascular events compared to those in the top 25%. Even more striking, people below the average for their age and sex are four to eight times more likely to have metabolic syndrome (a cluster of conditions including high blood pressure, high blood sugar, and abnormal cholesterol) compared to the fittest group.
Average VO2 max values by age, measured in mL/kg/min:
- Ages 20–29: 43 for women, 54 for men
- Ages 30–39: 40 for women, 49 for men
- Ages 40–49: 38 for women, 47 for men
- Ages 50–59: 34 for women, 42 for men
- Ages 60–69: 31 for women, 39 for men
- Over 70: 27 for women, 34 for men
Activity level matters enormously. An active man in his 50s averages 47, while an inactive one averages 38. For women in the same age bracket, active averages 37 versus 31 for inactive. Many smartwatches and fitness trackers now estimate VO2 max using heart rate data during walks or runs. These estimates aren’t lab-grade, but they’re useful for tracking trends over time. A clinical cardiopulmonary exercise test with a mask and treadmill gives the most precise number.
Heart Rate Recovery
Heart rate recovery is a simple test you can do anywhere with a heart rate monitor. It measures how quickly your heart rate drops after intense exercise, which reflects how well your autonomic nervous system controls your heart. The protocol is simple: note your peak heart rate at the end of a hard effort, then rest completely for one minute and check again. Subtract the second number from the first.
A drop of 18 beats per minute or more after one minute is considered good recovery. A smaller drop suggests your cardiovascular system is under more strain or less well-conditioned. This metric improves with consistent aerobic training, making it a useful way to track whether your fitness is actually improving week to week.
Heart Rate Variability
Heart rate variability (HRV) measures the tiny fluctuations in time between each heartbeat. Higher variability generally signals a healthier, more resilient cardiovascular system. Low HRV is an independent marker of mortality risk. HRV declines naturally with age, dropping to roughly 60% of young-adult baseline values by the 80s and 90s for some measures. The steepest decline happens in the metrics most sensitive to the branch of your nervous system responsible for rest and recovery, which can drop to about 24% of baseline by the 60s before leveling off.
Many wearable devices now report HRV, usually as a single overnight average. The absolute number matters less than your personal trend. A consistently declining HRV, or one that doesn’t recover after rest days, can signal overtraining, poor sleep, illness, or chronic stress. There aren’t universal “normal” HRV targets because individual variation is enormous. A 30-year-old endurance athlete might have an HRV of 80 ms while a healthy but sedentary person the same age sits at 35 ms. Track your own baseline and watch for sustained changes.
Coronary Artery Calcium Score
A coronary artery calcium (CAC) scan uses a quick, low-dose CT scan to detect calcium deposits in the arteries feeding your heart. Calcium builds up inside arterial plaque, so the score reflects how much atherosclerosis has already developed. A score of zero indicates very low risk. Scores of 1 to 10 suggest low probability of significant disease. Scores of 11 to 100 indicate mild or minimal narrowing. Between 101 and 400, non-obstructive disease is likely and obstruction is possible. Above 400, there is a high likelihood of at least one significant blockage.
The most powerful predictions come at the extremes. A zero score is strongly reassuring, and a score above 1,000 carries serious risk. Scores in the middle range are less precise at distinguishing individual risk levels. CAC scans are most valuable for people in the intermediate risk zone, where the result can tip the decision on whether to start preventive treatment. They’re not routinely recommended for low-risk adults or for those who already have confirmed heart disease.
10-Year Risk Calculators
Risk calculators pull several individual measurements together into a single probability: your chance of having a heart attack or stroke within the next 10 years. The standard calculator uses your age, sex, race, total cholesterol, HDL cholesterol, systolic blood pressure, whether you take blood pressure medication, whether you have diabetes, and whether you smoke. A version that substitutes BMI for cholesterol values exists for situations where bloodwork isn’t available.
These calculators are free online and take about two minutes. The resulting percentage shapes clinical decisions. A 10-year risk above 7.5% is the threshold where more aggressive prevention, including medication, becomes the standard recommendation. Even if none of your individual numbers look alarming, the combination of borderline values can push the overall risk higher than you’d expect.
What Wearables Can and Can’t Do
Consumer smartwatches are surprisingly accurate at detecting atrial fibrillation, the most common dangerous heart rhythm. Devices using optical pulse sensors (the green light on the back of your watch) detect atrial fibrillation with pooled sensitivity around 97% and specificity around 97%. Smartwatch ECG features, which require you to touch an electrode on the watch crown, actually perform somewhat lower in studies, with sensitivity around 83% and specificity around 88%. Combining both methods pushes accuracy above 97% sensitivity and 99% specificity.
Where wearables fall short is in measuring the clinical biomarkers that require a blood sample: cholesterol, blood sugar, CRP, and apoB. They also can’t detect calcium deposits or measure blood pressure with clinical precision (though wrist-based blood pressure features are improving). Think of your wearable as a strong tool for tracking trends in heart rate, HRV, VO2 max estimates, and rhythm abnormalities, while relying on periodic lab work and clinical visits for the biomarkers and imaging that complete the picture.