Before the arrival of smartwatches, people often didn’t take their heart rates seriously. Of course, heart rate is just one piece of the puzzle called health. But it’s a good place to start. That was the case with 25-year-old Sharath Sriram, a software developer from Bangalore.

Sharath’s life revolves around coding, which requires a high degree of focus. But one’s health can go downhill quickly if the company you’re working in has a toxic work culture. Sharath realised this last year and his Apple Watch became his friend during the difficult phase.

He joined a tech company around April last year and like anyone else, the idea was to stay there as long as he could. Somehow the support he was receiving from the “main leadership wasn’t great”. “There was a lot of friction. It was a little bit toxic and causing a lot of stress for me. Also, a lot of people were leaving because of this reason. At some point in October-November we were working on a new feature launch. That meant working long hours and working nights and weekends. Working such long hours is anyway taxing but on top of this when you are not being treated the right way, things become difficult,” said Sharath.

Around November it became very stressful and “unbearable”. He understood it wasn’t working out between him and his company but thought he “would give it some more months and complete a year before moving to a new company”.

Soon after Diwali, he started getting a lot of high heart rate notifications on his Apple Watch. Each time he went to a meeting, there were four-five such notifications, with readings like 130-135. “I would have short bursts of fever, like for three-four hours, after such meetings. Seeing those heart rate notifications I decided to get it checked out by a doctor,” said Sharath who uses the Apple Watch Series 8.

The doctor took an ECG and soon found physically he was fine. “It was mental stress that was taking a toll on his physical health. My overall resting heart rate was also very high. My doctor said I needed to get my health in order, otherwise there would be long-term issues,” he said.

The optical heart sensor in Apple Watch uses what is known as photoplethysmography. This technology is based on a simple fact: Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. The optical heart sensor supports a range of 30–210 beats per minute. In addition, the optical heart sensor is designed to compensate for low signal levels by increasing both LED brightness and sampling rate.

For most people, it is considered normal to have a resting heart rate between 60 and 100 beats per minute, according to the American Heart Association. Generally, a lower resting heart rate is associated with higher cardiovascular fitness.

Sharath decided it wasn’t worth continuing with the company he was working with and soon after moved to a new company. “I quit on December 1 and around December 5-6 I opened the Health app to find that my resting heart rate was down to 71 (from 83). I wrote an email (a couple of days ago) to Tim Cook (Apple CEO) because I realised the importance of mental health. Had I not followed the Apple Watch readings and gone to a doctor, my health would have deteriorated. My doctor said other serious issues would have cropped up in a few months,” said Sharath.

His message is simple: Mental health needs to be taken seriously as much as physical health.