“If you zoom out into the future and you look back and you ask the question ‘What was Apple’s greatest contribution to mankind?’ It will be about health,” said Apple CEO Tim Cook during an interview with CNBC earlier this year.

Cook’s prediction may be bold, but it isn’t surprising. The iPhone has had built-in health and fitness tracking features for years and the Apple Watch is one of the best smartwatches and fitness trackers around. Now with potentially lifesaving tech built-in, it’s becoming much more than a lifestyle device.

But with such a big commitment to health, why is the Apple Watch still missing one key feature: native sleep tracking?

According to a Bloomberg report from February 2019, Apple is allegedly working on a sleep monitor that’ll be added to a future version of the Apple Watch. The report states that the company has been trialling the sleep-tracking feature at Apple HQ and plans to add it to its smartwatch by 2020.

But given it’s taken the company so long and it has also acquired a sleep monitoring company in Beddit, what would Apple need to do to integrate sleep tracking into its smartwatch? And would it bring a new understanding of our sleep or offer the same type of data as the competition?