Microsoft has unveiled its first wearable device that can track a user's sleep and exercise as well as connect to a health service on smartphones.

The Microsoft Band will retail for $199 (£125) on the company's online store.

The device can operate for two days on a single charge and has 10 sensors that can track heart rate, calories, stress and even a person's sun exposure.

It marks Microsoft's latest push into digital health after its medical record initiative HealthVault in 2007.

"This is just the beginning of a multi-year vision for Microsoft in the health & fitness and wearables category," the company said in an emailed statement.

"We want to enter this space in a deliberate and measured fashion and as such are launching first in the United States."