India UK & Europe

Measure What Matters

We started Fourth Frontier in 2016 with the goal of helping people make the most of the time they spend exercising. Frontier X is our first offering towards achieving this vision.

Frontier X is a premium science backed wearable that helps you perform your best at all the activities you love, without straining your heart, going out of condition or injuring yourself—by measuring the metrics that matter.

Frontier X differs from other wearables in the market with its ability to measure whether your heart is receiving enough O2, breathing rate and internal training load across activities.

Whether you’re training for a 3-hour marathon or you’re a weekend dancer, you will benefit from knowing exactly how your body is reacting to the grind you are putting it through.

Merely knowing the number of times your heart beats through your run won’t tell you if it’s being over-strained.

Similarly, the number of calories you burn in a bout of boxing won’t tell you if you exercised to the optimum levels you were capable of that day.


We can tell you the exact level of exertion your body is experiencing on any given day, which helps you determine the right intensity levels to achieve your endurance or high intensity workout goals.


We ensure your workout is not over-straining your heart and keep your heart safe from any microtraumas it might sustain otherwise.

Training Optimization

We measure your week on week training load across activities and use this to make sure your current week’s load is not putting you in either undertraining or overtraining zones.

Our Team

Sandeep Sibal
Co-founder and CEO

“Frontier X is a gamechanger. It was built to solve long-standing problems that athletes have had for decades. Am I training and racing at the optimum intensity level? Am I pushing my heart too hard? Am I overtraining or undertraining? These are questions that cannot be answered well with a wrist-worn device because the answers are best found close to the heart and lungs. Our revolutionary chest-worn device uses technologies built for smartphones but applies it in the context of human performance and health. It is extremely satisfying to see legends like Paula Radcliffe believing in our product, philosophy and purpose.”

Manav Bhushan
Co-founder and CTO

“Over three-and-a-half years of research and development are behind the launch of Frontier X, which has been lab-tested and validated in trials by runners at World Marathon Majors and other races around the world. Frontier X provides users with detailed physiological data that previously was only available in testing through sports medicine labs and doctor’s offices. Fourth Frontier has filed four patents related to Frontier X and has made presentations at medical conferences in the United States and Europe.”