While I respect that any particular individual may have an idiosyncratic experience, the wealth of data in the field of circadian rhythms make it clear that travel in the Westerly direction conforms to normal daily rhythmic changes and therefore allows for easier adaptation. No need for me to roll my eyes on this....

My worst experience was after a huge night out in Cancun and only an hour's sleep. I then took a flight without sleeping to Miami and then onto London. I landed at 6am and turned up at the office to show willing. Unfortunately the .... had just hit the fan and I ended up doing Excel modelling until 11pm.

The last few hours I had to change the resolution down on my monitor as my vision had gotten so bad that I wasn't able to read the numbers.

I have heard about/read studies, but I don't really care.. sometimes I just feel like crap even when I am "supposed" to feel better than on some other flights. Yes, I did say that Asia Pac is the worst, which is very consistent, and Europe is usually fairly easy, but there have been exceptions.

One exception to note is that I always feel terrible after going to Brazil. It's far, but not in terms of time zones, but for some reason it'll take me a few days to recover..... and I promise it's not just too many caipirinha's when I'm in Rio!

My first trip to Europe many years ago as a college student visiting family, I made the mistake of going directly to bed after landing in the morning. Slept until 3 p.m. and never got back on track. For the next two weeks I was up all night and sleeping most of the day and very cranky.

Second worst experience was my second trip to Singapore. I landed on a Friday and thought I'd given myself enough time to acclimate before beginning 4 consecutive days of training presentations on Sunday. I did okay for the first two days, but it really hit me on Tuesday. I remember standing up in front of the room, swaying back and forth, and my participants laughing at me saying, "You're jet-lagged!"

Mine was the return leg of an Antarctic expedition. We flew USH-SSA-DUS-LHR-BAH, and it might have taken me over a week to fully recover from the jet lag.

I don't travel longhaul alot.

My worst experience would have to be this summer in the United States. I headed to Florida for five weeks and adjusted to their time zone. While the five hour time difference isn't alot the flight messed it up for me.

Flight left at 11pm and arrived at 10am, however, it was more like 5am for me. I didn't get any sleep because I don't sleep on planes and even if I did sleep it would've only been for 3 hours. Then when I got home I slept all day so I messed it up even more. It was daylight 1 hour into the flight.

After that I did try and sleep but my brain refused to switch off before 5am in the morning. Eventually I just gave up and stayed upto 3am everynight watching sitcoms.. I did get it fixed but it took me three weeks.

I don't know how people adjust to 10 hours of eastbound jetlag nevermind 5. I always read people online telling you to goto bed at a normal time but they seem to forget that you will not be tired at the "normal time". I will be booking the day flight with Aer Lingus this summer.

Not true for me. It takes me about 2 days to adjust to 5 hours westbound and 2 weeks eastbound.

Eastbound transatlantic fights are hellish in the summer.. Dark and then 1 hour later is broad daylight.

Thats exactly what I did this summer lol. It took me forever to fix

SIN-LHR-DEN last July and I caught something nasty on the plane. Jet lagged for week+ and in and out of the hospital for 3 days.

Back in 2008 when two trips ran back to back.

- Thursday, flew a redeye PHX-CLT
- Friday, flew CLT-DTW, went out to Ann Arbor to see my brother
- Saturday, flew DTW-BWI, drove to DC, saw an Orioles game, drove back to Baltimore
- Sunday, flew BWI-DTW, then DTW-ORD-DEN-PHX
- Monday, flew PHX-CLE for a work trip

When I woke up in Cleveland that Tuesday morning I felt dead. It was one of the hardest days I've ever had to get through. I had planned the visit to my brother and our pop down to DC for the game before I knew about the work trip. In retrospect I should have just flown to Cleveland from Detroit.

A long weekend NYC - HKG (cash in AA miles for one econ seat, companion flies free on Cathay Pacific) -- we were up at something like 5AM, drank all of the in-room coffee before the breakfast room opened, and were nodding off at early dinners.

Thankfully, I am fairly immune to jetlag, as I only require one night's sleep to fully adjust. I can also sleep anywhere, regardless of noise levels, which helps immensely.

Unfortunately, my wife, with whom I frequently travel on longer trips, is affected by time changes as little as 5 or 6 hours for several days.

Five or six hours is not a small time change. It's fully 50% of the maximum possible.

You're very lucky, and rare, if you can really adjust that quickly. :)

I have little problem with 8-10 hours going to Europe/Middle East, and no problem going to HKG, but coming back to YVR seemed to take a long time to recover from, maybe 10 days or so. I was shocked, although I had read about this problem.