The following post is a question answered by Frank Dolan from the Nike Training Network on the Nike Training Club App.
Question: Sport specific: soccer - Running on recovery days, what heart rate should I achieve to stay at and for how long?
Answer: Heart rate training zones vary from person to person based on a variety of factors. On a recovery day you would want to stay between 60-70 % of your maximum heart rate. In order for you to get your specific heart rate zones I would recommend getting a sub-maximal VO2 test to get all three of your training zones (recovery, moderate intensity, interval). You could also go "low tech" by way of perceived exertion. On a scale of 1-10 (10 being at failure), what is your heart rate when you feel you are at a 4, 5, or 6? That could represent your recovery zone. A typical recovery day training session should be between 30-60 minutes.
See NTC App: https://apps.apple.com/us/app/nike-training-club/id301521403