A part of most traveler’s lives,  jet lag is the undesirable but common side effect of just about any trip into a new time zone. While it affects everyone differently, if you travel you will probably experience jet lag in some form or another. Resulting from a disruption in the circadian rhythm, jet lag can throw our bodies, minds, and day to day life into disarray.

The circadian rhythm is the name for the regulatory system that our bodies employ to tell us when to sleep and wake throughout the day. The National Sleep Foundation describes it as “basically a 24-hour internal clock that is running in the background of your brain and cycles between sleepiness and alertness at regular intervals.” Crossing through time zones disrupts this natural process, leaving our body confused.

Reinvented budget airlines and cheaper plane tickets have made flying to another place more accessible than ever before. Travel is no longer thought of as an activity solely for the rich and famous or, on the other end of the spectrum, the broke backpacker. Instead, it has become a common part of many people’s lives.

While some of us may be quite familiar with the effects of jet lag, there are a surprising set of symptoms that we might not realize is a result of our recent travels. Or, if you are new to the travel world, perhaps all of these feelings come as a surprise.

20 Meal Times Are All Messed Up

In the same way that your body is trained to sleep during a certain part of the day, so is it trained to eat. Whether it’s five small meals, the traditional breakfast, lunch, and dinner, or maybe even a random assortment of snacks throughout the day, most people have an eating schedule. When traveling into another time zone, your body confuses it’s meal times. Don’t be surprised to find yourself eating takeout leftovers at 5:00 A.M. local time or wishing for a cup of coffee right before bed. Your body is still on the eating schedule you left behind and might take a bit to recognize the new pattern for your current time zone.

19 A Loss of Appetite

Not only will you potentially be craving a full breakfast in the middle of the night, but you might also be afflicted with a loss of appetite. One of the body’s other reactions to the strange shift from one-time zone to another, you may completely stop craving food, even if it has been a while since you last ate. It’s not uncommon to want a meal, sit down to eat it, and suddenly lose interest. Your appetite might fluctuate a lot in the days after a trip as your body adjusts and the jet lag fades.

18 Anxiety and Mood Swings

Anxiety can be a traveler’s companion in so many instances. Long periods of discomfort--i.e. wedging your body into a teeny-tiny economy seat for hours on end--can make it more challenging to deal with the mental discomforts that arise after landing in a new time zone. The stress that naturally comes from displacing yourself can accumulate and manifest into anxiety or show itself with mood swings. Through the disrupted sleep cycle, strange eating times, and other symptoms, jet lag can create or add to the nerves of already tense travel days, potentially leading to anxiety or other changes in mood. If you already have anxiety or mood swings normally, they might be a bit more intense than normal during jet lag.

17 Irritability For Days

Like anxiety, irritability can show up with other symptoms of jet lag. Naturally, we tend to feel a bit less like ourselves when we are physically out of whack. Traveling into another time zone is a strain on the body, and as such, on the mind. You may find yourself feeling more annoyed than you normally would at say, that person who is slowly, slowly, making their way off the plane after a very long flight. These minor inconveniences can show as more intense emotions than usual during the post-travel jet lag days.

16 Digestive Issues

Issues in the digestive system are a natural byproduct of travel. Usually, travel has us eating different kinds of foods and switching around meal times to accommodate an altered schedule. This can cause its own set of problems for our digestion, but it can also start even earlier with the onset of jet lag. Showing up in different ways, these issues are a set of reactions that the body has to the shock of traveling to another time zone. How the digestive system will react varies. Things such as constipation, diarrhea, or indigestion are common side effects of jet lag. For some especially unlucky travelers, it may show up as all three.

15 Difficulty Concentrating

Most of us have experienced those hard-to-keep-your-eyes open kind of days, usually stemming from a late night or overall lack of sleep. When we feel like that, it can be hard to focus at all let only get anything done. Jet lag leaves us with that same dragging exhaustion. Our minds are a bit soupy after all that travel and sleep deprivation. Even simple tasks can feel much slower like they are being dragged through the mud. Trying to wrangle a tired mind to stop it from wandering is challenging making it very difficult to concentrate.

14 Dehydration Can Sneak Up On You

The body goes through quite a lot when it is pushed into a completely different time zone. The combination of a long flight, where most of us tend to drink less water, and the consumption of less hydrating foods leaves the body a bit dried out. Prolonged exposure to this type of environment is pretty much unavoidable if you’re traveling for long distances. In addition, travel days can feel busy and hectic. Many of us forget to drink water, don’t even think of it, or simply don’t prioritize staying hydrated while we are traveling. All of this can lead to a bout of dehydration, another symptom of the dreaded jet lag.

13  Muscle Soreness

Muscles can feel very sore after switching into another time zone. Stemming from the dehydration, and likely the act of manipulating our bodies into the weird positions that come with long plane rides, our bodies can be misaligned and achy by the time we step off the plane. This soreness can show up just about anywhere in the body and for any amount of time, can be quite uncomfortable and potentially also lead to cramping.

12 Oh, The Malaise

There are those times where we feel a bit heavier when things that are normally easy might be a bit of a struggle. Feeling like you are walking in a fog, a general blah feeling, or everything being just slightly off. When you’re experiencing this, you may be in a malaise. also a fancy way of saying, something just doesn't feel right. With the exhaustion, physical discomfort and potential ailments, and stress on the body and mind from travel, it makes sense that you might not feel yourself afterward. This malaise can follow you throughout your jet leg, hampering recovery. It shouldn’t last longer than the other jet lags symptoms, hopefully letting you get back to enjoying your travels as quickly as possible.

11 A Lowered Immune System

Most people who travel frequently have a story of being sick right after a flight. While we accept a possible sickness as part of the travel experience, why this happens is a bit of a surprise. It’s not just the exposure to other people’s germs in a tight space--i.e., your seatmate on the plane coughing the whole ride--that has us downing Vitamin C before we travel. In addition to having run-ins with more illnesses than normal, flying also lowers the body's ability to fight them off. All the symptoms on this list combined with a temporarily weakened immune system can make us more vulnerable to getting sick while traveling.

10 Exhaustion & Insomnia

Ok, so maybe this isn’t a surprise, but it has to be included when talking about jet lag. Even if you have technically gotten enough hours of sleep, the body is so confused about when to sleep and wake that you will likely have periods of total exhaustion. It may be misplaced, with you struggling to stay awake in the middle of the day or waking at strange hours in the middle of the night. On the flip side, there may be nights where you simply cannot sleep, having hours of boundless energy when you wish you could be sleeping.

9 Lack of Productivity

Tired? Distracted? Hungry? Maybe not hungry at all? There are so many feelings, emotions, and confusion about those feelings and emotions that it is almost impossible to get anything done when experiencing jet lag. Even the things that do get done might take a little longer or not be performed at the level that you are used to. Don’t be surprised to see this temporary drop in productivity when arriving in a new place and again when returning home. The sightseeing might go a bit slower than normal as your body adjusts to the new time zone, and your work might suffer a bit when you return home.

8 The Direction You Travel Will Impact Which Jet Lag Symptoms You Have

Not only does it matter how long you travel for, but the actual direction in which your plane heads can greatly impact the jet lag that follows. Traveling Eastward versus Westward can actually determine the types of jet lag symptoms that you are susceptible to. Let’s use New York City as an example. If you travel from New York to Los Angeles, traveling westwards through time zones, you may experience a more restless sleep and earlier mornings. On the other hand, traveling East to London, you would likely have a more difficult time falling asleep at night. In addition, traveling East goes against our bodies natural clock, doubling the effect of jet lag on these trips.

7 Headaches, Headaches, Headaches

Pressure, loud noises, dehydration, exhaustion, and all the other stressors that come with travel are the perfect recipe for the next symptom on this list. As if you needed another potential physical ailment to make your adjustment to a new place any more challenging, headaches can be quite common with jet lag. The intensity of a headache varies as do the chances of experiencing them during this time, but they can come on at any time and stay for any amount of time. While that throbbing feeling in your skull may come as a surprise, it will likely fade with the other jet lag symptoms.

6 Swollen Feet and Ankles

Plane rides often have us sitting for hours straight without moving, not to mention the seats leave much to be desired. Combine this with the dehydration that usually accompanies a flight and the body reacts by storing water. The result of all of this is an uncomfortable swelling around the feet and ankles. If you’re someone who takes your shoes off in flight, it may be challenging to fit them back over the swelling upon landing. Don’t be surprised to feel some extra water weight around the feet and ankles for hours or even longer after heading into a different time zone.

5 Airplane Ear Is No Fun

Most of us have experienced airplane ear in one form or another. The clogging and popping feeling that comes from the rapid pressure change through taking off and landing will cause some form of discomfort to most travelers. There are more extreme symptoms of this as well such as a subtle, dull, ringing in the ears. This is hit or miss, not everyone will experience it, but the ringing can be quite persistent. Lasting for days or longer after a long flight, it is an irritating leftover of travel. Be especially careful if you have sinus issues going into the flight, trying to clear the clogged or “popping” ears is one way this gets started.

4 Motion Sickness Will Get You

Motion sickness is a fickle thing. It can pop up regularly for years and then suddenly disappear or show up randomly for someone who has never experienced it before. Any kind of travel can cause motion sickness, whether you are on a plane, car, or train. If there is movement, there is a chance for motion sickness if you are susceptible to it. The motion sickness that accompanies jet lag can be especially challenging because longer travel will often combine multiple of these transportation methods. It’s not uncommon to take a flight to a new place, then hop in a car or train (or both) to get to where you need to be. This prolonged movement can take a toll on the already weary body, making motion sickness more intense, last for longer, or appear for people who normally do not suffer from it.

3 It's Disorienting

Have you ever woken up after a long flight and been completely confused? What day is it? Where am I? How did I get here? That foggy brain feeling is totally normal and usually clears up after a few clarifying clues, like your phone connecting to local time and seeing an airport sign stating where it is that you just landed. When you are jet-lagged, however, this feeling can last longer. The body and mind will be a bit out of sync with each other and the new location for a bit. There may be quite a few morning wake-ups that are confused, or moments of disorientation throughout the day, as you get adjusted.

2 Look Out For Vertigo

You know that unbalanced, loss of equilibrium feeling that can make the room feel like it’s spinning or you’re walking on the fluid ground? That might be a case of vertigo, causing sensations that will make the body feel totally disoriented. Vertigo can be a catalyst for other side effects of jet lag, such as headaches and nausea, playing into the larger role of “I just don’t feel well” that traveling to a new time zone can bring. Vertigo can be frightening but if it is stemming from a recent trip will usually pass as the jet lag passes.

1 Nausea Is No Joke

Often a byproduct of one of the other symptoms--like vertigo, digestive issues, and dehydration--nausea is yet another side effect of jet lag. There are so many components to jet lag that make you feel unwell. An uneasy stomach is yet another one. Nausea can be a symptom of another jet lag symptom or exist on its own. For example, if the actual movement of the plane, train, or car that you are in makes you feel nauseous, it may be from motion sickness. But it’s also very normal to feel nausea creep up all on its own.