Fitness trackers have changed the way people think about health. Beyond counting steps and calories, modern wearables now estimate metrics such as fitness age, cardiovascular age, cardio fitness score, and even WHOOP Age. These numbers are designed to simplify heart health and make it easier to understand.
Many users check these scores regularly, hoping to see improvements over time. While the idea of having a "younger" heart can be motivating, cardiologists say it is important to understand what these measurements actually represent and what they do not.
The good news is that the habits linked to a healthier cardiovascular profile are straightforward. Small improvements in daily routines can positively influence many of the metrics tracked by wearable devices and, more importantly, support long-term heart health.
What Does “Heart Age” Actually Mean?
Before focusing on lowering a heart age score, it helps to understand what the term means.
According to Sharonne N. Hayes, MD, cardiologist and founder of the Women's Heart Clinic at Mayo Clinic, there is technically no medical diagnosis called "cardiovascular age."
"You cannot change the age of your heart," Dr. Hayes explains.
A heart ages alongside the body. What fitness trackers estimate is not the actual age of the organ. Instead, they use various health markers to estimate cardiovascular fitness and disease risk.
These scores provide a simplified way to think about heart health. They combine several measurements into a single number that is easier for most people to understand.
That distinction matters because the real goal is not reversing age. The goal is to reduce the likelihood of heart disease and cardiac events.
Why Fitness Companies Created These Scores
Freepik | Modern fitness trackers use simplified metrics like fitness age to make heart health easier to understand.
Wearable manufacturers use different names for similar concepts.
Garmin offers a Fitness Age metric, while Oura provides a Cardiovascular Age estimate. Fitbit includes a Cardio Fitness Score, and Apple Watch users can access similar assessments through the Fitness Age app. WHOOP also calculates its own version, known as WHOOP Age.
Garmin describes Fitness Age as an estimate of fitness level compared with biological age.
David Lammers-Meis, Manager of Fitness Product Management at Garmin, explains that the calculation combines several heart-focused measurements, including:
1. VO2 max
2. Resting heart rate
3. Workout intensity
4. Population health data from the Centers for Disease Control and Prevention (CDC)
5. Information from the World Health Organization (WHO)
Oura takes a similar approach.
Chris Curry, MD, Clinical Director of Women's Health at Oura, says the company analyzes data such as heart rate, heart rate variability, sleep patterns, and daily activity levels to estimate how efficiently the cardiovascular system functions.
Although the exact formulas differ, the objective remains the same: encourage people to pay attention to their heart health.
Why Heart Health Deserves Attention
Cardiologists agree that anything encouraging people to focus on prevention is valuable.
Heart disease remains the leading cause of death worldwide. In the United States alone, approximately 2,500 people die every day from heart-related causes, according to the American Heart Association. That equals one death every 34 seconds.
Despite those numbers, there is encouraging news.
Stacey Rosen, MD, cardiologist and Executive Director of the Katz Institute for Women's Health at Northwell Health, points out that most heart disease is preventable.
That is one reason many physicians support the use of cardiovascular age scores as motivational tools.
Tamanna Singh, MD, cardiologist and Director of the Sports Cardiology Center and Stress ECG Lab at Cleveland Clinic, explains:
"By addressing something like 'cardiovascular age,' you're automatically addressing a lot of those risk factors that can increase your morbidity and mortality."
Dr. Hayes shares a similar view.
"'Age' is fun—and it's a nice thing to grab onto."
Even though these scores are not formal medical measurements, they often reflect health behaviors that genuinely influence cardiovascular wellness.
How Wearables Can Support Heart Health
Fitness trackers should never replace professional medical care. However, they can provide useful information when viewed as part of a bigger picture.
Aaron Leigh Baggish, MD, founder and director of the Cardiovascular Performance Program at Massachusetts General Hospital and professor at Université de Lausanne, believes one of the biggest benefits is long-term trend monitoring.
"Wearables allow you to put numbers over time to your body," he says.
Rather than focusing on a single day's result, users can monitor patterns across weeks and months.
Freepik | Wearables make healthy habits easier with smart reminders, workout adjustments, and recovery tracking.
For example, improvements in cardiovascular age may suggest healthier habits are developing. Changes in resting heart rate, heart rate variability, activity levels, and VO2 max can also indicate whether fitness is moving in a positive direction.
Modern wearable technology has become increasingly accurate when estimating these metrics, although the numbers are not perfect.
Many devices also encourage healthier daily behavior. Some wearables send reminders to stand up after prolonged sitting. Others suggest workout adjustments, activity targets, or recovery recommendations.
These prompts may seem small, yet they support habits linked to better cardiovascular outcomes.
Dr. Curry believes this contributes to greater health awareness.
"For us, it's that idea of prevention. It is that idea of body literacy, and the notion that you have some control over the trajectory of your health and well-being."
The Health Markers That Matter Most
The American Heart Association highlights what it calls Life's Essential 8, a framework focused on the most important measures and habits for cardiovascular health.
Four of these are measurable health markers:
1. Cholesterol
Low-density lipoprotein (LDL), often called "bad" cholesterol, plays a major role in cardiovascular risk. For most adults, an LDL cholesterol level below 100 mg/dL is considered desirable. Lower levels are generally associated with lower risk.
Since wearables cannot measure cholesterol, routine blood testing remains essential.
2. Blood Sugar
Blood sugar affects blood vessels, circulation, and overall heart health. A fasting blood glucose level below 100 mg/dL is generally considered healthy.
Monitoring blood sugar becomes particularly important for individuals with diabetes, prediabetes, or metabolic concerns.
3. Blood Pressure
High blood pressure places additional strain on the heart and arteries. A healthy blood pressure reading is generally below 120/80 mmHg.
Because high blood pressure often produces no obvious symptoms, regular screenings are important.
4. Weight
Body weight alone does not determine health. However, a higher body mass index (BMI) is associated with increased risks of hypertension, glucose intolerance, prediabetes, and several metabolic conditions that can affect cardiovascular function.
Dr. Rosen notes that BMI is not a perfect measurement, but it remains one of the commonly used tools for evaluating risk.
Ways to Improve Your Heart Age
The remaining four components of Life's Essential 8 focus on daily behaviors.
These habits influence many of the same metrics used by wearable devices to calculate cardiovascular age.
1. Prioritize Quality Sleep
Sleep is the newest addition to the American Heart Association's framework, and its importance continues to grow.
Most adults function best with seven to nine hours of sleep each night, although individual needs vary. Poor sleep has been associated with elevated blood pressure, blood sugar problems, lung disease, and cardiovascular conditions.
Dr. Rosen explains:
"We know that those who don't get healthy sleep have troubles with blood sugar, with hypertension, with lung and other heart disease."
Many fitness trackers provide detailed sleep reports. Yet even without technology, energy levels, alertness, and overall recovery can offer meaningful clues about sleep quality.
2. Follow a Heart-Friendly Diet
Magnific | Boost your heart health and manage your weight by adopting a diverse, Mediterranean-style diet.
Nutrition directly affects cholesterol, blood pressure, blood sugar, and weight management.
Cardiologists often recommend a Mediterranean-style eating pattern that includes fruits and vegetables, whole grains, legumes, nuts and seeds, healthy fats such as olive oil, and moderate amounts of fish and lean proteins.
At the same time, limiting heavily processed foods, excess sugar, and large amounts of red meat can support better cardiovascular outcomes.
3. Stay Physically Active
Exercise remains one of the most effective ways to improve cardiovascular health.
The American Heart Association recommends between 75 and 150 minutes of moderate-to-vigorous physical activity each week. That target does not require intense athletic training.
Walking, cycling, dancing, hiking, swimming, jogging, and recreational sports can all contribute.
4. Avoid Tobacco Use
Smoking remains one of the most significant risk factors for cardiovascular disease. Quitting tobacco improves circulation, reduces blood pressure, lowers heart disease risk, and benefits nearly every organ system.
Even long-term smokers can experience measurable health improvements after quitting.
Why Trends Matter More Than Numbers
One of the biggest mistakes wearable users make is obsessing over individual readings.
Heart rate variability may fluctuate. Sleep scores can vary. Fitness age estimates may rise or fall from week to week. Those short-term changes rarely tell the whole story.
Instead, physicians recommend focusing on broader trends. Improvements sustained over months often provide a clearer picture of overall cardiovascular progress.
At the same time, physical symptoms should never be ignored. As Dr. Singh notes:
"Data is just data—you know your body best."
No wearable can fully replace personal awareness or professional medical evaluation
Heart age scores may not reflect the heart’s actual age, but they can highlight factors that influence cardiovascular health. These scores are often based on lifestyle habits and health markers such as physical activity, sleep quality, diet, smoking status, cholesterol, blood pressure, blood sugar, and weight.
While fitness trackers are not diagnostic tools, they can help users monitor trends and stay motivated to maintain healthy routines. Used alongside regular medical checkups, they can support better awareness of heart health and encourage long-term preventive care.
