When he first felt the pressure on his chest, my father was halfway through his morning walk. By the time my mother, who was walking a few feet ahead of him turned back, his forehead was clammy, and he was breathing in great gulps of air through his mouth.

Forty-eight hours, an ECG, a stress test, and an angiography later, we knew why: my father had four blockages in his coronary arteries, three of which were over 90%. His choked arteries were starving his heart of blood. It was a miracle, said the doctors, that he hadn’t had a heart attack yet. His only option was bypass surgery.

The day they wheeled him into the operation theatre on a scorching May afternoon was déjà vu: five years ago, I had seen my paternal grandmother wheeled through the same doors for the same surgery.

Awareness about heart health, and the factors that lead to cardiovascular meltdown, was unusually high in my family. My grandmother was a lifelong diabetic who used to calmly jab herself with insulin shots every evening as I watched in horrified fascination. And long before my father had a heart surgery, he was diagnosed with diabetes and high-blood pressure.

Doctors I have spoken to say that given my family’s predisposition towards heart disease, my chances of getting something are fairly high — unless I eat well and gets lots of exercise. Which is why I’ve watched the rise of fitness trackers with growing excitement over the last few years.

According to market analyst IDC, 100 million wrist-based wearable devices are expected to be shipped around the world by the end of this year, compared to 72 million in 2015. But here’s what’s happening: the ability to monitor your heart rate, which has only been available on high-end, professional-grade fitness trackers, is suddenly being offered as a standard feature even on mid-range trackers that are relatively more affordable. You can buy Fitbit’s Charge HR on Amazon for about ₹13,000, for instance, while TomTom’s Runner Cardio Sports Watch is available for ₹15,000.

Both companies entered the Indian market last year, and both tout the ability to track your heart rate through the day, and when you sleep and work out, as a key reason to chose their pricier models over the cheaper ones that don’t offer heart rate monitoring.

Look, I’m not running scared. But having a family history of heart disease means that when I come across statistics like India’s two million annual heart attacks, my heart rate does go up. I have guilt pangs every time I dig into French fries, and every few months, the idea of getting a yearly cardiac checkup seems more and more appealing.

When I bought the Apple Watch last year, my only thought — besides thinking how overpriced it was, of course — was this: could this device that sits on my wrist actually save my life one day?

Heart rate: A history

The answer to that question seems to be yes. In March, a 62-year-old Canadian man’s Apple Watch alerted him of an unusually high heart rate. He immediately called an ambulance and was taken to a hospital where surgeons saved his life by clearing blocked arteries.

“Your heart rate is one of the easiest variables of your health to measure,” says Dr. Aniruddha Chandorkar, a leading Pune-based cardiologist. “That’s one of the main reasons why it’s part of so many fitness trackers today.”

Most modern smartwatches and fitness trackers, use photoplethysmography – send me a tweet when you can pronounce that – to tell you how fast your heart is beating. The heart rate sensor in your Fitbit or your Apple Watch shines bright LEDs into your skin to detect the amount of blood flowing through your capillaries, which is then used to calculate your heart rate using sophisticated algorithms (this is a vastly simplified explanation, but you get the idea).

Strapping a device to your wrist to track your heart rate might seem futuristic, but the idea is nearly 40 years old. In 1977, a Finnish electronics professor named Seppo Säynäjäkangas was skiing cross-country near his home in Kempele, a small town in northern Finland, along with a friend who happened to be the coach for the Finnish National Cross Country Ski team. His athletes, thought the coach, could be far more efficient at the sport if only there was a way to accurately measure their heart rates during training. Could the professor do something?

Professor Säynäjäkangas did three things: he set up a company called Polar Electro in the same year; he filed for a patent two years later; and five years later, in 1982, he released the Sport Tester PE2000, the world’s first wrist-based wireless heart rate monitor. Today, Polar is still a leading maker of heart rate monitors and fitness trackers.

The PE2000 didn’t have LEDs. Instead it worked by sensing your body’s electrical signals through your skin, and amplifying them to calculate your heart rate. If you’ve ever used the stainless steel handlebars on the treadmill at your gym to measure your heart rate, or had a cardiologist give you an ECG, it’s the same technology at work.

And while opinions about the accuracy of heart rate monitors in fitness trackers differ greatly (just ask Fitbit), there’s consensus around one thing: if you’re serious enough about this stuff to cough up the extra bit of cash for a fitness tracker with a heart rate monitor, you’re likely to be paying more attention to your fitness levels in general.

How much data is too much data?

It’s just after seven on a muggy morning in May, and my rubber-soled feet are pounding the pavement. My shirt sticks to my back, and I can feel hot beads of sweat trickling through my hair. I’ve been going at a steady pace for about 10 minutes when my Apple Watch taps me on the wrist.

Instinctively, I bring my wrist up and glance down mid-run. My heart rate shows up in big, bright numbers on the watch face, and right now, it is edging past 170 beats per minute. Instantly, I start slowing down and watch my heart rate fall down to 166…to 163…to 160 – right where I want it.

I started tracking my body’s fitness statistics long before the Apple Watch released in 2015. When the Fitbit Flex, the company’s first wrist-based fitness tracker launched in 2013, I immediately sprang for one. The Flex didn’t have a heart rate monitor, but it tracked the basics – the number of steps I walked each day, the number of calories burnt, and how well I slept each night.

The Fitbit Flex completely changed how I thought about fitness. Abstract concepts like “activity” were suddenly quantified and laid out in slick charts on my phone. “Sleep” was a series of thin blue lines.

I was hooked. Suddenly, everything had to have a numeric value – the calories in the food I consumed every day, the amount of water I drank every 12 hours, the flights of stairs I climbed daily, and the distance I biked each weekend.

When the Apple Watch came along, I added heart rate to the mix. Suddenly it wasn’t enough to know how many steps I walked each day. I had to know what my average heart rate was before I went to bed, and what my resting heart rate was when I opened my eyes in the morning. It wasn’t enough to go for a run, it was important to know if I was running in the right zone where my heart rate wasn’t too low or high but just right, for maximum efficiency.

Fuelling my obsession with heart rate data is a ₹200 Apple Watch app called HeartWatch, created by a Sydney-based software developer named David Walsh. Walsh, whose wife is a national-level sprint coach, has been a fitness nut for years. “I’ve got abs,” he proclaims in a blog post.

The inspiration for HeartWatch is rooted in tragedy. When he was 20, Walsh’s father, who was a passionate sportsman, died of a heart attack in the middle of a soccer game. He was 56.

The death was unexpected. “ had recently had a checkup and was given a clean bill of health,” wrote Walsh on his blog. “The thing is, with heart problems, sometimes the problem only appears when you aren’t having the check up. A bit like when your car has that annoying noise that miraculously disappears as soon as you drive into the service centre.”

Modern cars have onboard computers that record faults and show technicians what’s going on when you take them in for repairs. The Apple Watch with its heart rate sensor, reasoned Walsh, could be used as an onboard computer for the human body.

HeartWatch was released in December 2015 to rave reviews. “From a health perspective, the most important thing to look at is what your heart is doing when you are not exercising,” Walsh tells me over email. This is what the app excels at.

The Apple Watch measures your heart rate every 10 minutes, and it is this data that HeartWatch uses to paint a mind-bogglingly detailed summary of your heart activity through the day.

Using a series of colourful circles – blue indicates regular heartbeat, yellow indicates heart rate during an active workout, and red indicates an abnormally high heart rate – HeartWatch paints a comprehensive picture of how your heart is beating at any given point in time. The more blue you have, the better. If you’re seeing too much red, it may be a cause for concern.

If you wear your Apple Watch to bed as I do, HeartWatch will also track your pulse through the night and give you your resting heart rate in the morning. The lower your resting heart rate, say cardiologists, the healthier your heart is.

Walsh says that he didn’t have a target audience in mind when he built the app, but that he sees everyone from serious athletes to people who simply love diving into granular data using it.

“Measuring your heart rate every 10 minutes is quite extreme and not very useful medically,” says Dr. Chandorkar. “It doesn’t define healthy versus unhealthy. As a cardiologist, I care about doing an overall assessment of your heart depending on your risk factors like heredity and how often you exercise.”

Most importantly, he adds, it is important to remember that your heart rate is just one among the many variables that matter. “It is true that fitter people, in general, have lower resting heart rates, but to put two people side by side and claim that the person with the lower heart rate is healthier is inaccurate.” The best way to keep your heart healthy, he says, are the tried and tested basics: exercise regularly, and eat right.

“Well, my Dad used to do that,” says Walsh. “But the way I think about HeartWatch is that it’s a bit like one of those ‘Check Engine’ lights that you see in your car that makes you aware that you should get it checked. It’s no real effort to check it, and the potential benefits far outweigh any inconvenience.”

You are priceless

I love gadgets. And I’m borderline paranoid about my heart. So as companies cram more sensors into their devices , I’m excited about the future. The Microsoft Band, for instance, has an ultraviolet sensor that tells you if you’ve been out in the sun for too long; and the next version of the Apple Watch is expected to measure your body’s blood oxygen levels.

“From my perspective, the more sensors there are in these devices, the better,” says Walsh. “We are seeing the start of a whole new way that technology can improve our lives.”

Look, I’m not delusional. I know that if I sit on my butt all day, get no physical activity, guzzle Diet Coke, and stuff myself with Taco Bell, that beautiful, overpriced doodad on my wrist won’t do jack no matter how many fitness apps I load it up with.

But there’s merit in getting access to getting to the kind of granular data that modern fitness trackers provide you with so easily. If my father had an app to tell him what his average heart rate was every day, he could have potentially seen a pattern over time, and  went to a doctor long before he felt any chest pain.

If the Apple Watch — or any modern fitness tracker — can do that, does the price tag really matter?

Lead image: Pixabay

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