Program: Is there a cure for jet lag?

Tegan Taylor: Norman, you are such a jet-setter, I have got to know what your hack is for jetlag.

Norman Swan: It's changed actually. I used to take 10 milligrams of Valium, eat before I got on the plane, 10 milligrams of Valium, and then put on a big mask, my headset and a hoodie, and then fall asleep, convinced that that was really the best thing. And then what I've discovered more recently is actually not doing very much is actually the best thing, so not getting all uptight about it. So generally I eat before I get on the plane, don't eat very much on the plane. I've stopped drinking alcohol, that just really makes you feel crap at the other end. And I sleep whenever I feel like it. I don't try and force myself. So in other words, I get off the plane in reasonably good shape, ready to meet the day. I also find that if you can possibly do it, arriving home or in your destination in the evening so you go straight to bed is not a bad thing either, but it's not always possible. What's yours?

Tegan Taylor: Oh, mine is sort of similar to what you do these days, I kind of let nature take its course, try to avoid booze and kind of try to sleep when I can. But unlike you I try to eat when I can, because I know that if I get too hungry on a plane, I feel nauseous, and it is a yucky cycle to get into. 

Norman Swan: Well, it is depressing when you've had a good meal before you get on and the meal arrives and it smells nice, I'll have a little bit of that, and then it's all laid out before you.

Tegan Taylor: Well, jetlag is what we are talking about today on What's That Rash?.

Norman Swan: The podcast where we answer the health questions that simply everybody's asking.

Tegan Taylor: So this week's question comes from David who says, 'A real problem for some of us is jetlag. Do you have any tips as to what are the best ways of minimising it?' Well, Norman, maybe we've cut our own grass by sharing our own personal tips, but let us…

Norman Swan: But they're not scientific so…

Tegan Taylor: Well, yes, we should get into the science. I think that most people listening to What's That Rash? would know what jetlag is, but, just in case, a definition please.

Norman Swan: Well, various definitions, but basically the technical term would be asynchrony, that we're out of sorts with the environment, the day-night cycle, the sleep cycle, and the environment into which we've landed. And it usually occurs when you've gone through several time zones. And really what it is is a disruption of the whole body in many ways.

Tegan Taylor: Because usually our body clock is sort of reset each day by light and dark. Well, we have talked about this so much in various episodes of What's That Rash?, especially our most recent one that was on night owls and early birds, so you can go back and listen to that for a bit of a refresher. But basically our bodies have a master clock inside it that is sort of recalibrated or wound every day by the rising of the sun and the setting of it as well. And then when you go somewhere else and it only took you a couple of hours or a few hours to get there, but it's topsy-turvy, your brain just doesn't know what to do with it. 

Norman Swan: Yeah, every cell in the body has a clock, and that clock, without being told what to do, runs at its own setting. And the master clock, as you say, is really above the eyes, called the suprachiasmatic nucleus, which is a bundle of nerves sitting above where the nerves from the optic nerves in the eye cross over, and this monitors the light cycle. But it doesn't just monitor the light cycle, it's got nerve connections and neural networks passing right through the brain, so it has a biological effect as well, and a feedback loop that goes back to the SCN, and it entrains the rest of the body. So if the SCN is thrown out, the rest of the body is thrown out. And actually, contrary to common belief, it actually doesn't take long for the SCN to retrain its clock to a new day-night cycle, but it takes a while for it to get the troops in order in the rest of the body to follow its marching orders in terms of chronicity.

Tegan Taylor: The thing that I love doing with all of our episodes is to go back and delve into a little bit of the history here. And of course the term 'jetlag', of course it is a modern ailment, but it's so interesting to me to think about the fact that humans up until less than 100 years ago, maybe the last 70 or 80 years, it just wasn't possible to travel fast enough for this to be a problem. You could imagine if you were on foot or on horseback or even on a train, that you just wouldn't be able to go through enough time zones for it to really do a number on you without adjusting to it along the way, the way you can if you get on a flight in Sydney and you get off a flight in London less than 24 hours later, and it's upside-down land.

Norman Swan: That's right. So it's a phenomenon of air travel and really didn't register 'til the 1950s or so, because until then, as you say, people went slowly, they went across the Atlantic or the Pacific by ocean liner, or you went across continents by train, but then slowly and steadily it speeded up, so you were moving time zones incredibly quickly. And this is a new biological phenomenon in human history, and then it started to be described, and really aviation was where a lot of the original research took place.

Tegan Taylor: Yes, so the first commercial flight was in 1914 but it wasn't really 'til the '50s that you had more people in the United States, where these figures come from, travelling by air than by train. And so would you like to know when the first written mention of the term 'jetlag' was published? 

Norman Swan: When was it?

Tegan Taylor: 1966, an LA Times article that said, 'If you're going to be a member of the jet set and fly off to Kathmandu for coffee with King Mahendra, you can count on contracting jetlag, a debility not unakin to a hangover.' And a different article also from 1966 was talking about jetlag, saying, 'It takes eight days for the body's juices to return to normal after a long jet flight.' Disgusting.

Norman Swan: Well, in fact how long it takes (just coming back to the science) depends on how many time zones you've travelled, and so there's a fairly predictable rate of change. So if you've gone from Australia to Europe, you know, it can take five, six, seven days to reset your body properly. And repeated research shows that going westward is much more gentle on your body and your body clock than going eastward.

Tegan Taylor: Okay, I have a problem with this rule of thumb…sorry, I don't really have a problem with the rule, but I think that when you live in Australia, it's a little harder to generalise, because let's say you live in Greenwich and everyone's either up to 12 hours ahead of you, or up to 12 hours behind you, then going east or west makes perfect sense, but if I go west enough, it's almost like I've gone east.

Norman Swan: You're planning an around-the-world trip, are you, in a day?

Tegan Taylor: I mean, going to the States is super weird, and going to…

Norman Swan: Meaning because you pass over the dateline?

Tegan Taylor: You pass over the international date line, you're like a whole day out, and coming back is sort of the same. 

Norman Swan: But you're not really, if you go across the date line you end up…if you fly from the east coast of Australia to Los Angeles, the actual difference in time zones is very small. I should say it's much smaller than going to Europe, it's not small. But let me go back to that aviation research, because what they were concerned about with aviation was the effect on air crew of going through these changes. And they had done some research which suggested that the combination of the stress of landing, the cognitive stress, the physical stress of landing, showing how much heart rate goes up amongst pilots and so on, associated with cognitive disruption, with jetlag, they got worried that this was actually a serious risk of crashing and of accidents.

Tegan Taylor: But it is, so good on them for looking into it. Even with the greater confidence that we have in flying and aviation technology and the increased safety we have in the design of aircraft nowadays, it's still an issue that you are doing a number on your body system. It does have a cognitive effect.

Norman Swan: So that's where rules came in about rest periods and forced rest periods between flights and in the era of Concorde they actually argued that it might be better for pilots to fly from London to New York and then just stay on the plane and fly back, because that would have much less effect on jetlag, although the job strain of all those hours in a small cockpit would be considerable.

Tegan Taylor: So yeah, definitely a lot of research into what's safe and what works and what doesn't work. The thing that I found curious was that in one of these articles from 1966 it said that the advice for offsetting the syndrome, this jetlag syndrome that was newly described; sleeping, avoiding alcohol and eating lightly, which to my 2025 brain actually sounds like pretty sensible advice. Not much has actually changed over that time.

Norman Swan: No, and a lot of the advice, coming back to David's question, depends on what you're going to do at the other end. So, for example, if you are mission critical, you're flying to London to give an academic paper or a business meeting or something like that and you're only there for a short period of time, you want to be at your best and you're going to fly back quite soon, then the advice is actually to stay as much on home time, home meals, home activity and light exposure as you were back in Brisbane and Perth or Sydney, or wherever you started off from, whereas if you're going away and you want to minimise the jetlag over the first few days of your holiday, that's a different set of advice.

Tegan Taylor: One of the areas that there's a lot of research in here is actually sporting teams who have travelled around for matches. And early research was within America, sports teams travelling around to different time zones, and that the home advantage wasn't just the normal vibes of the hometown advantage but it was also the fact that the incoming players were perhaps a little jetlagged, even just by a couple of hours, and the home team were acclimatised already to their own time zone. 

Norman Swan: Yes, eastward was worse performance than going westward. If they actually acclimatise going eastward, there was no difference in score lines, controlling for the quality of the team. So yeah, big effects there according to which direction they travelled and how long they took to acclimatise. 

Tegan Taylor: I kind of jumped us past it before; can we talk a bit about this eastward versus westward direction of travel and why it's easier going one direction than the other. Has this got something to do with the cave experiment?

Norman Swan: It's partly to do with that. We've spoken about that before, that if you…

Tegan Taylor: I probably should define what the cave experiment is.

Norman Swan: Well, the cave experiment was putting people in a cave away from sunlight, and what was their sleep-wake cycle in complete darkness. And it turns out the natural cycle of human beings is longer than 24 hours, it could be up to 25 hours. So our natural cycle is actually to have a longer day rather than a shorter day. And going eastwards, the day shortens, and going westward, the day lengthens. Therefore the theory is that's more in line with our natural, innate control of our body clocks. Let me just describe what this is in practical terms, because it's actually easier to understand in practical terms. If you're going westward, your bedtime is usually delayed.

Tegan Taylor: So I've flown to New Zealand. I've gotten there, it's 6pm in my brain, but it's 9pm in Wellington.

Norman Swan: That's right. So that's going eastward…

Tegan Taylor: Oh, that's east, sorry!

Norman Swan: But let's stick with New Zealand being eastward, so it's 9pm and therefore the whole social thing is, well, it's 9pm, I'm going to go to bed, but your body is actually only at 7pm and therefore you're forcing yourself to go to bed at a time where your body's not ready to go to bed. That's much harder than when you go westward, where your bedtime is actually later than it otherwise would be. It's much easier for us in general to delay sleep, hold off and go to bed at a reasonably normal hour than it is to force ourselves to go to bed early. So you have a bare night sleep on your first night away and feel better for that.

Tegan Taylor: Which is part of your thing, which is basically, like, get in as close to your normal bed time as you normally would and go to bed on your first…because no matter where you're coming from, you're almost always shattered at the end of a long travel day, and going to sleep that first night often isn't so much a problem, it's the subsequent nights that are hard. 

Norman Swan: Yeah.

Tegan Taylor: So Norman, let's imagine that we are elite athletes, we're heading to the big game, and we want to ensure that we have peak performance as quickly as possible once we get to our destination. What do we do?

Norman Swan: So it's an important caveat that you're really wanting to be at peak performance when you get there, so you start adjusting your schedule three or four days beforehand, and that's light exposure, sleeping times, meal times, and slowly moving towards your destination time. So you don't start a big jump to destination time over three or four days, you adjust to it, so that by the time you get on the plane you're roughly at destination time in terms of your eating and light exposure. The hard thing is light exposure on the plane, because that's not necessarily adjusted to your destination time, but that's the way they do it. And then when they get off, really adjusting very, very quickly to local time.

Tegan Taylor: What about, say, caffeine to keep you awake, or something like melatonin to get you to go off to sleep?

Norman Swan: So caffeine just papers over the surface, keeps you awake for a little bit longer, but not necessarily alert, it doesn't change your body clock. Melatonin, if you just take it at night to fall asleep, it almost certainly doesn't alter your body clock. If you want it to alter your body clock, you've got to take it at different times during the day according to which way you've gone, west or east. So if you want to get to sleep earlier and adjust your body clock that way, some people would argue that you take melatonin actually in the afternoon. And if you wanted to go to sleep later, you take melatonin in the morning. So this is a way of readjusting your body clock, rather than necessarily getting you off to sleep.

Tegan Taylor: Really the biggest fantasy in this is that either you or I are elite athletes.

Norman Swan: Yeah, or indeed travelling so much that it matters.

Tegan Taylor: We can dream. So I feel like what we've mostly spoken about so far has been very much the immediate term of, like, I need to be great when I get home, or I need to be great when I get to my destination, and so how can I do that short-term? I do want to talk about long-term effects of jetlag though, like if you're a real jet setter, you're someone whose work takes you all over the world, or if you're a pilot or flight crew or cabin crew who are travelling through time zones all the time, what do we know about prolonged or frequent jetlag in terms of our long-term health? 

Norman Swan: Surprisingly little. When you look at air crew, you're talking about people who are well tested, particularly on the flight deck, who tend to be fitter than average. So there is a little bit of evidence of increased cancer rates, a little bit of evidence of increased type 2 diabetes and overweight and so on. But this is not strong evidence. And for example, the cancer has also been put down to high altitude flying and exposure to radiation in the air. So these things are complicated. And what's been studied much more in-depth is shift work, but we're not talking about shift work today, we're talking about jetlag.

Tegan Taylor: Well, they're sort of the same thing. If you're flight or cabin crew, you are shift working as well as travelling through time zones, it must be pretty hard to unstitch those two things.

Norman Swan: Well, you're shift working for the length of the flight and then changing your shift for the next day. It's moot whether it's actually shift work or just perpetual jetlag.

Tegan Taylor: But we don't really know.

Norman Swan: No, there's a little bit of evidence of it being unhealthy, but it's not strong.

Tegan Taylor: Not enough to counteract the glamour of travelling the world, and all the duty-free you can buy.

Norman Swan: Yeah, of being somebody who serves you food and cleans the toilets, that's right, very glamorous. 

Tegan Taylor: So I feel like we've talked around it a lot, Norman, let's give David a straight answer; is there anything we can really do to cure jetlag?

Norman Swan: Yes, is the answer to David, which is follow the modern advice, which, as you've said, Tegan, is also the old advice, which is, don't do anything special, don't drink alcohol, don't eat a lot on the plane, get off the plane and try and stay awake until it's the bedtime of the place that you're at. If you're going eastward, that's harder to do. But the next day, get out and exercise in the sun and expose yourself to the light-dark cycle. Sunlight is the most effective source of light for resetting your body clock. Artificial light can do it, but it's not as efficient. So exercise is a very strong re-setter of the body clock. It's called a zeitgeber. And then it's just your body habits, it's eating, it's getting your metabolism in train.

Tegan Taylor: Norman, I thought I said a cure but what you've just said is sensible management advice. I really wanted something I could take and then just have it fixed.

Norman Swan: Yeah, well, that's what people take melatonin for but, as we just said, it's not as simple as taking a large dose just before you go to bed. So small doses of melatonin don't seem to work, it's got to be a reasonable dose, so around about five milligrams is what they say, but taken at the times we just said, not necessarily taken at the time of going to bed. So there's no cure, there's maybe a little bit of help along the way, but it's the natural stuff that works. 

Tegan Taylor: Well, actually, Norman, in our mailbag today we have a jetlag cure provided to us, not related to David's question. Jonathan has said, 'Jetlag has come up on the show a few times recently, and so I thought I'd share a possible solution. Last weekend I returned from Europe…' Okay, flex, Jonathan…

Norman Swan: Yeah, nah nah nah-nah nah, okay!

Tegan Taylor: 'Usually,' he says, 'that would mean waking up in the middle of the night for at least a few days. This time, on the day I arrived, I developed symptoms of a winter cold, sore throat, fatigue, runny nose. I slept for 11 to 12 hours each night for six nights. No jetlag. Can't say I recommend it as a strategy though, as the cold has been fairly unpleasant.'

Norman Swan: Yeah, you get nowt for nowt in this world, as they used to say. And we've also had some feedback from Matt. 

Tegan Taylor: Yes, Matt really loved last week's podcast on Bryan Johnson and the Don't Die movement. But Matt is querying as to why he's never heard us talk about any other prominent figures in the longevity game, namely Dr Peter Attia and Dr Rhonda Patrick, given their expertise on the subject. And he is kind of low-key accusing you, Norman, of not wanting to talk about Attia because he also has a book which competes with your book.

Norman Swan: I'm not in Peter Attia's league. I wish I was, you know, because I'd be going to Europe with Jonathan.

Tegan Taylor: Attia focuses on something he calls health span, which I know I've heard you talk about before, Norman, several times, but one point of difference is that Peter doesn't advocate for the Mediterranean diet nearly as much as you do. He focuses on protein in particular for older people, which assists to offset sarcopenia or muscle loss. Matt says he knows that we have a whole episode dedicated to protein, but just thought it would be interesting to hear your thoughts on these two giants in the longevity game.

Norman Swan: So health span is what counts. Nobody wants to live a long time in misery. So health span is, you know, how long you live in good health. Protein is important, particularly as you get older, we talked about that in the protein episode. I'm just a little bit reserved about the Peter Attia story because some of it is solidly evidence based, some of it's right out on the edge. It's not as much out on the edge as Bryan Johnson. And therefore I'm probably a bit more conservative.

Tegan Taylor: Not you with the low-key throw-down, Norman. Are you going to fight Peter Attia if he ever listens to this episode?

Norman Swan: He's got much more muscle than I have…

Tegan Taylor: Yeah, because of all the protein! Well, Matt, enjoy your various longevity sources of truth. Thank you for including us in that list, and keep living, I guess. Keep on sending us emails for as long as you manage to live in good health.

Norman Swan: And we'll see you next week. 

Tegan Taylor: See you then.