Best energy tracker for consultants

The energy tracking space has roughly 40-60 consumer apps competing (Oura, Whoop, Apple Watch integrations, plus generic habit trackers), but almost none are built for the consultant's actual pain point: linking energy fluctuations to project profitability and client outcomes. The common failure is treating energy as a personal wellness metric instead of a business metric. Most existing tools show you that you're tired; they don't show you that you're tired during your most billable hours or which client types drain you fastest. The real gap is that consultants need real-time energy scoring linked to calendar, project, and billing data—not another meditation app or sleep tracker. A vibecoder entering this space should focus on one thing: making energy an input to better project pricing and scheduling, not an output metric for self-optimization. This means integrations with Toggl, Clockify, or Harvest matter more than sensor accuracy.