Jet Lag Circadian Light Planner
Synchronize your body clock before you land. Calculate custom bright light, light avoidance, and melatonin windows based on flight timing and sleep biology.
Flight Itinerary
Habitual Sleep
Day-by-Day Biohacking Protocol
The Science of Circadian Jet Lag Management
Jet lag is not merely feeling tired; it is a clinical condition known as **circadian desynchrony**. It occurs when the master pacemaker in your brain—the suprachiasmatic nucleus (SCN)—is out of sync with the physical day/night cycle of your destination. This disrupts melatonin secretion, core body temperature cycles, cortisol rhythms, and digestive activity.
The Temperature Minimum (Tmin)
Your body temperature fluctuates on a 24-hour cycle, dropping to its lowest point (Tmin) roughly 2 to 3 hours before your natural wake time (typically around 4:00 AM). Tmin is the critical inflection point of the human **Phase Response Curve (PRC)**. Light exposure right before or after this point determines how your clock shifts.
Phase Advance vs. Phase Delay
Eastward Travel (Phase Advance) shifts your cycle earlier. Light exposure *after* Tmin advances your clock, while light exposure *before* Tmin delays it. Westward Travel (Phase Delay) shifts your cycle later. Light exposure *before* Tmin delays your clock, while light exposure *after* Tmin advances it.
Melatonin Timing Rules
Melatonin is a hormone signaling darkness. For eastward travel, taking a micro-dose (0.3mg to 3.0mg) 30–60 minutes before your target bedtime at the destination acts as a phase advance trigger. For westward travel, melatonin is generally not needed, but can be taken at destination bedtime to sustain sleep.
Natural vs. Artificial Light
The SCN is highly sensitive to blue wavelength light (460–480 nm). Direct sunlight provides up to 100,000 lux and is the best tool. If your "Seek Light" window falls during destination night hours, you must use a dedicated 10,000 lux light box or blue-light-emitting therapy glasses to trigger the shift.
Scientific References
- New England Journal of Medicine: "Circadian rhythms and travel: Mechanisms and management of jet lag."
- Lancet: "Jet lag: etiology, prevention, and treatment protocols using bright light and melatonin."
- Journal of Biological Rhythms: "The phase response curve of human circadian pacemakers to bright light."