Tools
Free Health OS online tools: timers and tests grounded in sleep and productivity research.
Japanese Walking Timer
Free Japanese walking interval timer: 3 minutes fast, 3 minutes slow, 5 rounds = 30 minutes. Sound and vibration cues before every pace change.
Reaction Time Test
Free online reaction time test: 10 trials, random wait, same design as the sleep-research PVT. Median, lapses, and your own baseline over time.