Your Heart Holds the Clues: Using Wearables to Decode Cardiovascular Health

We live in an age where your watch can tell you more about your health than some annual check-ups. But with so much data from wearables, such as heart rate, VO₂ max, heart rate variability (HRV) and even blood pressure, how do you know what matters? And, more importantly, how do you use that data wisely?

As a doctor working in precision health, I’ve seen firsthand the growing reliance on wearable technology to guide training, track recovery, and even detect illness. The promise is huge, but only if we interpret these signals correctly. I use patient wearable data when planning their health journeys and I am very excited to see this sector grow in its ability.

Here’s what you need to know about the five most meaningful cardiovascular metrics you can track from home, and what they can reveal about your current and future health.

1. Resting Heart Rate (RHR): Your Daily Baseline

• A consistently lower resting heart rate (RHR) typically reflects good cardiovascular fitness and a well-regulated nervous system that supports rest, recovery, and overall balance (known as healthy parasympathetic function or vagal tone).
• A sudden rise in HRH may signal poor sleep, high stress, or even illness.

Top Tip: Track your RHR over time in the morning before caffeine, movement, or stress.

2. Heart Rate Recovery (HRR): The Speed of Recovery

• Measures how fast your heart rate drops after exercise.
• A higher drop (≥20 bpm after 1 min) reflects better cardiovascular resilience.
• Low HRR (<12 bpm) is associated with increased mortality risk and it is one of the clearest red flags wearables can detect.

3. Heart Rate Variability (HRV): Your Stress & Recovery Barometer

• HRV measures the slight differences in time between each heartbeat. It reflects how well your nervous system manages stress and recovery, with higher HRV generally indicating better resilience, recovery, and overall health.
• Personal trends matter more than comparisons to others when it comes to HRV.
• Exercise can lower HRV, during the exercise.
• Chronic stress, alcohol, illness, or poor sleep have been shown to suppress HRV.

Top Tip: Look at rolling averages (e.g., 30-day trends), not daily highs/lows.

4.  VO₂ Max: Your Aerobic “Horsepower”

• A key predictor of longevity that has strong data in the scientific literature.
• Improves with structured aerobic training, particularly Zone 2 + HIIT exercises for 45 - 60 minutes.
• Best tested in-clinic, during exercise, but wearable trends can still offer directional insights now.

5. Blood Pressure: The Silent Force

• Elevated BP increases cardiovascular and dementia risk, often being present with no symptoms at all.
• Aim for <120/80 mmHg at rest, using a electrical cuff, not a watch.
• If it is more than 120/80 mmHg, you may be best seeking advice from your healthcare provider to look into catching and treating this early.

So, now you know more about the metrics, what can you now do?

• Measure smart: Use validated tools and track at the same time daily.
• Train smarter: Combine low-intensity cardio (like brisk walking, cycling, or gentle jogging) with short, intense efforts that push your heart rate near its maximum, such as 30 second sprints or hill climbs. This blend improves both your aerobic base and your peak cardiovascular performance, supporting heart health and overall fitness.
• Sleep deeper: Prioritise consistent wake times, cool/dark bedrooms, and longer winding-down evening routines.
• Manage stress: Even 10 minutes of slow breathing or walking can meaningfully improve HRV and RHR.
• Use data wisely: Let metrics guide trends and recovery, but don’t obsess over every number.

Wearables aren’t perfect, but when used thoughtfully, they can offer a powerful, continuous glimpse into your cardiovascular and autonomic health. Used wrongly, they can become a source of anxiety or misinformation. Your metrics are not the goal. Your health is.

I’d love to hear how you use wearable data, what’s worked for you, and what hasn’t?

Dr Michael Barnish MBChB