References behind the clinical content in 336.
The clinical timeline, withdrawal facts, and tactical advice shown in the 336 app are drawn from the following primary sources — peer-reviewed journals, U.S. and international health authorities, and clinical patient-education materials.
Smoking & Tobacco Use — Health Effects
Centers for Disease Control and Prevention (CDC)
Cardiovascular and respiratory recovery timeline after quitting smoking.
Tobacco Cessation Treatment Guideline
U.S. Preventive Services Task Force (USPSTF)
Evidence-based cessation interventions and clinical recommendations.
Nicotine Addiction: Pharmacology and Treatment
National Institute on Drug Abuse (NIDA / NIH)
Nicotine pharmacokinetics, half-life, and dependence biology.
Effects of abstinence from tobacco: Valid symptoms and time course
Hughes JR. Nicotine & Tobacco Research, 2007;9(3):315-327.
Withdrawal symptom timeline — cravings, irritability, sleep disturbance, mood.
How Tobacco Smoke Causes Disease — Surgeon General's Report
U.S. Department of Health and Human Services, 2010.
Carbon monoxide displacement of oxygen and hemodynamic recovery after quitting.
The Health Benefits of Smoking Cessation — Surgeon General's Report
U.S. Department of Health and Human Services, 1990.
Long-term recovery milestones (24 hours through 15 years post-quit).
Pharmacokinetics of nicotine after intravenous administration
Benowitz NL, Jacob P. Clinical Pharmacology & Therapeutics, 1990.
Plasma nicotine half-life of approximately two hours; metabolic clearance.
Carbon monoxide elimination kinetics in humans
Peterson JE, Stewart RD. Journal of Applied Physiology, 1970.
Carboxyhemoglobin half-life of 4–6 hours on room air.
Sleep disturbance during smoking cessation
Jaehne A, Loessl B, Bárkai Z, Riemann D, Hornyak M. Sleep Medicine Reviews, 2012;16(4):363-377.
REM rebound, vivid dreams, and insomnia patterns during nicotine withdrawal.
Quit Smoking — Patient Education
Mayo Clinic
Tactical advice for cessation: hydration, breathing, craving management.
World Health Organization (WHO)
Global cessation guidance and population health data.