OS States

Ultradian Rhythm

Biological cycles shorter than 24 hours — e.g., 90-minute focus cycles, 20-minute rest.

Ultradian rhythms are biological cycles that repeat more than once per 24 hours. Examples include the 90-minute sleep cycle, the 90–120 minute basic rest-activity cycle (BRAC), and shorter attention cycles.

Key Cycles

  • 90-minute cycle — deep work, creative flow
  • 20-minute cycle — short breaks, recovery
  • Neurotransmitter depletion — focus depletes; rest restores

In ONDA Life

Part 8 "Ultradian Optimization" works within natural rhythms (90/20-minute cycles) for the timely restoration of neurotransmitters. Working against these rhythms leads to cognitive burnout; working with them supports neural resilience.

Scientific Basis

Built on: Polyvagal Theory (Porges); Psychoneuroimmunology (Ader & Cohen); neuroplasticity research.