Staying for many hours in an enclosed space will have an effect on your health. There are various problems that can happen, here are some of them:

• Cold and flu: Air inside passenger jets are re-circulated and filtered, but that doesn’t reduce the possibility that flu will spread. If you sit within two rows of someone who has flu for eight hours or more, you will be infected as well. To reduce risks, you should wear mask and keep your hands clean. Avoid touching objects that may people touch as well, such as door handles of the toilet. When you go to the restroom, always wash your hand and use a toilet paper to open the door. If possible, you should bring sanitizer with you at any time. You should clean your hand before eating or sleeping. It’s true that sanitizers can’t kill virus, but it may remove debris that carries virus, so always wipe your hands after using sanitizer. Low humidity inside the airplane will make mucus in our nose thicken and dry up. It means that cilia or fine hair inside our nose will stop working properly. Because mucus doesn’t function, it will be easier for germ to colonize the interior of our nose, causing infection more likely to happen. During a long flight, you should try to keep yourself well hydrated. Avoid drinking coffee, because this will cause to have trouble sleeping. It’s also a good idea to take vitamin supplements before, during and after the flight, so your immune system will remain strong.
• Deep vein thrombosis: When you sit in one position for too long, blood clot could form in deep veins of your legs. Symptoms of DVT include swelling and pain in the calf. It’s a risky condition, because the clot may break off and get logged in the pulmonary artery that’s connected to the long. This condition is also known as pulmonary embolus, which is potentially fatal, because oxygen exchange between lungs and blood will be disrupted. If possible, you should move your lays, stand up and walk occasionally. If you can’t walk, you should at least stand up for a few minutes while shaking your feet. You should wear loose shoes and clothes, as well as drinking plenty of fluids. Avoid alcohol whenever possible and take aspirin before you go to sleep, which can help to slightly thin your blood.
• Jet lag: Jet lag happens if you cross many time zones in a short period of time. The internal clock of your body will have trouble adapting. Symptoms of jet lag include headache, night time insomnia, sleepiness during the day, irritability, gastrointestinal problems and loss of appetite. To adapt yourself to the drastically different time zone, you should rest for at least one day. So, you need to adjust your schedule. Regulate the exposure of the light. If you travel eastward, you need to go to bed earlier, a few days before the flight. If you travel westward, you should sleep later. Take gradual adjustments, so your body can adapt better. If you do this, it’s not necessary for you to do many adjustments in the destination area.