The software, which was developed by Chelsea Football Club's Chelsea Digital Ventures and digital healthcare experts HUMA, assesses seven lifestyle characteristics that have all been validated as important predictors of disease and mortality. The following are examples of these:

1. Self-reported health - because you know your body best, the app asks you how you feel about your overall health.

2. Resting heart rate - by merely laying your finger over the smartphone's camera, the app can calculate your resting heart rate.

3. Sleep - the app includes a quiz that asks you how many hours you slept on average in the previous week and how good your sleep was.

4. Cigarette consumption - the number of cigarettes consumed on a weekly basis.

5. Alcohol intake - the type(s) and amount of alcoholic beverages you consume on a weekly basis.

6. waist-to-height ratio - the waist circumference is determined using the camera on your smartphone.

7. Reaction time - a basic test in which you lift your finger when the color of a shape changes.

After users finish each domain – which should take no more than ten minutes – they are given a point-based score, or 'C-Score' (a number between 0 and 100), reflecting their overall health. The higher your C-Score, the healthier you are in general.

The score is compared to 500,000 persons in the UK Biobank, a national health database comprised of individuals aged 40-69 years who shared their health data between 2006 and 2010 and are still contributing data to enable health tracking.

Users will be able to view how their health compares to that of people in the UK Biobank, as well as what percentage of persons in the UK Biobank provided similar or dissimilar responses or had data in the same or dissimilar range as them.

While the C-Score domains do not encompass all of the factors that contribute to one's health or illness, they are modifiable indicators that scientists and clinicians have identified as having the greatest impact on a person's overall health and as indicators of all-cause mortality in the medical literature.

They were chosen using the following criteria:

Review of the medical literature:

• Huma's clinical and scientific team undertook a literature analysis of around 500 publications to identify relevant areas for an all-cause mortality index.

24 prominent opinion leaders from three continents were interviewed.

• Refinement of relevant domains involving 24 key thought leaders from the UK, US, and China, including Dr. Smisha Agarwai of John Hopkins University, Prof. Kamudi Joshipura of Harvard School of Public Health, and Dr. You Cian Lin of China Medical University.

• Validation of a final 7 metrics with KOLs that focus on academic and clinical significance while also being actionable and easy to evaluate by the public at large C-Score does not require invasive hospital tests, a visit to the GP, or expensive wearables, while the existing BMI model represents populations, not individuals.

C-Score is a health app that lets to measure their overall health in only ten minutes using their smartphones.