Withings has launched the next version of its Pulse activity tracker, now called Pulse O2. The new device allows users to measure their blood oxygen levels, which help users understand the efficiency of their overall lung functions.

This tool is especially useful for people who work out in high altitudes, for example mountain climbers, or people with respiratory issues, such as asthma or chronic bronchitis. Withings said the device can guard against hypoxia, a condition in which the body is deprived of oxygen, but Withings has not had Pulse O2 cleared with the FDA.

Another company, Masimo, launched an iPhone connected pulse oximeter, called iSpO2, back in December 2012, and that device also did not have FDA clearance. iSpO2 was marketed for climbers and pilots.

Pulse O2 has a similar form factor to its predecessor -- it can clip on to user's clothing or just sit in the user's pocket -- but now also offers users the option to wear the device on their wrists.

Like Pulse, Pulse O2 also measures heart rate, tracks activity, records sleep and syncs to an app that also helps users log food.

Pulse's companion app, Health Mate, was also redesigned to use the data from Withings devices to coach the user and provide him or her with actionable advice. The new coaching features are available through the app's Smart Insights section, which shows the user’s progress, the Healthy Reminders section, which helps him or her adopt the right habits, and the Leaderboards section, which provides motivation through competition. These items are organized in Withings Health Mate's new Timeline view.

Pulse O2 is on sale over at Withings' website for $119.95.

Withings initially launched Pulse in June 2013, following an announcement about the device at CES. At this year's CES show, Withings previewed two new devices, a Bluetooth-enabled update of the company’s upper arm blood pressure cuff and a two part sleep tracking system. The sleep system, called Withings Aura, is not a wearable device. Instead, the system consists of a sensor placed in the user’s bed and a bedside device that serves as both lamp and alarm clock. The system is controlled via a smartphone app.