Crank Up Your Training
Buy one of the Garmin watch devices (for runners, skiers or multisport the most top model is Forerunner 920XT) or Polar (V800, M400 models are the best). It allows users to create any training session on a PC. Then the workout will show up on the watch and walk the athlete through the training session, by giving triggers to start warm ups/intervals/rest/cool downs.
So you can try this way:
1. Take a Garmin or Polar watch.
2. Create training plan for each exercise session on PC:
Garmin Connect https://connect.garmin.com or
3. Sync training plan with watch.
4. Control HR or the training parameters during the workout, by looking at the watch (without earbuds).