NYC to LON

Jetlag Guide for JFK → LHR (5 Hours Eastward)

Expected Symptoms and Timeline

• Common symptoms: Difficulty falling asleep at local bedtime in London, early-morning awakenings, daytime sleepiness, brain fog, reduced concentration, irritability, and digestive upset (constipation or mild stomach discomfort).
• Onset: Symptoms usually start on arrival day and are most noticeable in the late afternoon and evening when your body still thinks it’s earlier in New York.
• Duration: For a 5-hour eastward shift, most travelers feel significantly better after 3–4 days if they manage light and sleep well. Without any strategy, some people may feel off for up to 5–6 days.
• Who is most affected: Night owls, people with strict routines, those on short trips (3–4 days), and anyone needing to perform at a high cognitive level immediately (meetings, presentations).

Pre-Flight Preparation (3–5 Days Before Departure)

• Gradually shift your schedule: Move your entire routine (sleep, wake, meals) 30–60 minutes earlier each day for 3–4 days before departure. Aim to be 2–3 hours closer to London time by the day you fly.
• Anchor with morning light: Get bright natural light as soon as you wake up in New York. Go outside for 20–30 minutes; this helps your body clock start shifting earlier.
• Evening wind-down earlier: Reduce bright light and screens 60–90 minutes before your (new, earlier) bedtime. Use warm, dim lighting and avoid intense work or stimulating media.
• Caffeine timing: Keep caffeine to the first half of your day. Avoid caffeine within 8 hours of your target bedtime so you can fall asleep earlier.
• Consider low-dose melatonin (optional): If appropriate for you, a low dose (0.5–1 mg) taken about 4–5 hours before your current usual bedtime for 2–3 nights pre-trip can help shift your clock earlier. Check with a healthcare professional if you have any medical conditions or take regular medications.
• Plan your flight time strategically: For overnight flights, choose a departure that gives you at least a 3–4 hour window to rest. For daytime flights, plan to stay awake on board and sleep at a normal London bedtime after arrival.

During the Flight

• Set your watch to London time immediately: As soon as you board, mentally switch to UK time and start behaving according to that schedule (when to eat, sleep, and limit light).
• For overnight flights (most common JFK → LHR):
  • Try to sleep soon after the first meal service. Even 3–4 hours of light sleep helps.
  • Use a sleep kit: eye mask, earplugs or noise-cancelling headphones, neck pillow, and a light blanket or extra layer.
  • Avoid screens and bright overhead lights once you decide to sleep; use a dim reading light if needed.
• For daytime flights:
  • Stay mostly awake and active on board. Short 20–30 minute naps are okay, but avoid long deep sleep that will make it harder to sleep at London bedtime.
  • Expose yourself to light (open the window shade if possible) during the first half of the flight, then gradually dim light in the last 1–2 hours to prepare for London evening.
• Hydration and food:
  • Drink water regularly; aim for a glass every 1–2 hours. Limit alcohol to one drink or skip it entirely, as it fragments sleep and worsens jetlag.
  • Eat lighter meals. Avoid very heavy, greasy foods that can cause digestive discomfort when your body clock is out of sync.
  • Stop caffeine 6–8 hours before your planned London bedtime on arrival day.
• Movement:
  • Stand, stretch, and walk the aisle every 60–90 minutes when awake to reduce stiffness and improve circulation.
  • Do simple seated exercises: ankle circles, calf raises, and gentle neck and shoulder rolls.

Post-Arrival Adjustment in London

• Day 1 (Arrival Day):
  • Stay awake until a reasonable local bedtime (at least 9–10 pm London time). Avoid long naps; if you must nap, keep it to 20–30 minutes before 3 pm.
  • Get daylight exposure as soon as possible after landing. Spend at least 30–60 minutes outside, especially in the late morning and early afternoon, to push your body clock toward London time.
  • Eat meals on London schedule, even if you’re not very hungry. Light, balanced meals help reset your digestive rhythm.
  • Use strategic caffeine: a small coffee or tea in the late morning or early afternoon is fine. Avoid caffeine after about 3–4 pm local time.
• Nights 1–3:
  • Expect to feel sleepy early evening and to wake up very early. If you wake at 3–4 am, stay in low light, avoid screens, and try relaxation techniques (breathing exercises, light reading) to fall back asleep.
  • Keep a consistent bedtime and wake time (e.g., 10–11 pm to 6–7 am). Consistency speeds adjustment.
  • Use darkness at night: blackout curtains or an eye mask, and avoid bright screens for 60 minutes before bed.
  • If you struggle to fall asleep at local bedtime, a short warm shower, stretching, and a cool, quiet room can help signal sleep.
• Light and melatonin after arrival (optional):
  • Maximize morning light exposure (8–11 am) for the first 3–4 days. This is the strongest signal to shift your clock earlier to match London.
  • If recommended by a professional and appropriate for you, a low dose of melatonin (0.5–1 mg) taken 1–2 hours before your target London bedtime for the first 2–3 nights can help consolidate sleep.
• For short trips (3–4 days in London):
  • Still shift to London time, but focus on key performance windows (e.g., mornings for meetings). Use caffeine and light strategically during those times.
  • Accept that you may not fully adapt; prioritize sleep quality (even if slightly off-schedule) over forcing a perfect local schedule.

Summary

A JFK → LHR flight is relatively short for an overnight long-haul but involves a substantial 5-hour eastward time shift, making jetlag moderately to highly disruptive. By shifting your schedule before departure, managing light, sleep, and caffeine during the flight, and using daylight and consistent routines after arrival, you can usually feel functional by day 2 and close to fully adjusted by days 3–4.