First determine your maximum heart rate, since you’ll be basing most of your workout ranges on it. Warm up for 20 to 30 minutes, then do five all-out sprints of 45 to 60 seconds (for runners) or 90 seconds (for cyclists and swimmers). The highest number your monitor captures is your max.
Begin plotting workouts tailored to your goals. If you’re looking to finish an Ironman, load up your schedule with easy aerobic work (60 to 70 percent of your max), an intensity that builds endurance. Running a 10K or half-marathon? You’ll want a balance of threshold and economy training (90 to 95 percent) to maximize efficiency. And if you regularly train in open water or off-road, a heart-rate-monitor-GPS combo can help you maintain a consistent effort even when terrain or conditions vary.
Tracking your heart rate is an ideal way to monitor your fitness over time. If you’re working hard but not improving, check to see whether your heart rate is elevated in the morning or during easy workouts—classic signs of overtraining and a reminder to back off either your volume or your intensity. For hard-charging athletes, a monitor makes it easy to avoid creeping into threshold range on recovery days—a sure way to get injured—by alerting you when your heart rate gets too high.