Vocal exercises work best if you’re singing in chest or head voice on the notes where the vocal cords sit in that voice type naturally. In other words, not pushing the chest voice into the head voice's range, or not bringing the head voice down into the chest range, but allowing the natural ranges. Then voice development and strengthening occurs where the natural ranges are to create a connected, blended, unified, and resilient voice.
Vocal Lessons Worldwide: www.shanestewartvocalcoach.com