It takes practice but you should get better at maintaining a heart rate over time. Need heart rate to go down? Slow down, shorten stride. If a hill is steep enough you may need to walk. Need heart rate to go up? Push the pace!

I believe you can host your data if you prefer

Check out Helper Scripts. These make getting LXCs up and running super easy. This was built by a community member who recently passed away and he turned it over to the community before his passing. Its a great project!