The Garmin Forerunner 245 digs in a little deeper, giving you more insights to optimize your training for race day. In addition to tracking essential stats like heart rate, distance traveled, pace, cadence, and intervals, the Forerunner 245 captures ground contact time, stride length, vertical oscillation and ratio, more accurate VO2 Max measurements, and Pulse OX, your blood oxygen saturation levels. That data can be used to pinpoint deficiencies in your training, giving you the knowledge to know whether you need to build strength or get your form in check to take your performance further. The watch uses an optical heart rate monitor and GPS to track your metrics more accurately, and the watch can track sleep, stress levels, and menstrual cycles. You’ll also get smartphone notifications like calls and texts, plus a brand new incident detection feature that will automatically call for help if the watch detects that you may have been involved in an accident while on a run. The Forerunner 245 comes with a silicone strap and a 42 mm watch case, and is waterproof up to 5 ATM. Battery life is about a week when just used as a smartwatch, and up to 24 hours with GPS continuously turned on — long enough to last you through an ultra marathon!