Taking a long flight and thinking of enjoying a glass of alcohol before taking a nap? It may not be the healthiest thing to do. A new study has found that when people sleep after drinking alcohol at the low air pressure, which is usually experienced while flying, heart rates increase and blood oxygen levels drop. It may also lead to dehydration and dizziness. Staying hydrated is a must, especially while you are flying. So, instead of consuming alcohol, look for healthy drinks, especially the ones with electrolytes. Let us tell you some of the best drinks you can have on a plane.

Why should you avoid alcohol while flying?

When people go to sleep after drinking alcohol at the low air pressures experienced during air travel, their heart rates increase, according to a study published in the journal Thorax in June 2024. Researchers also found that blood oxygen drops to worrisome levels even in healthy and young people.

Forty eight healthy people aged between 18 and 40 participated in the study. They were divided into two groups — the first one went to a sleep lab with sea-level air pressure, and the second lot went to an altitude chamber. It had air pressure similar to that on airplanes flying at cruising altitude. In both the groups, 12 participants slept for four hours after drinking alcohol. It was equivalent to two beer cans or two glasses of wine. The other 12 participants in each group slept without having alcohol.

It was found that those who consumed alcohol before sleeping in the altitude chamber saw their blood oxygen saturation drop to 85 percent. On an average, their heart rates increased to about 88 beats per minute.

As for the participants who drank alcohol at sea level before sleeping, they experienced blood oxygen saturation dip to 95 percent. Their heart rates increased to 77 beats per minute, as per the study.

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Lack of oxygen pressure in planes reduces the quantity of oxygen in blood, and this can lead to increased chances of becoming dehydrated, says nutritionist Dr Rohini Patil. It can also raise the chances of dizziness, fatigue as well as headaches. Besides, alcohol increases the effects of jet lag and disturbs a person’s sleep patterns.

What to drink on a flight?

Staying hydrated, especially when you are on a flight, is important as planes have less humidity. This can make your skin and eyes dry. It can also provide an energy boost and strengthen the immune system. Also, when you drink water or other fluids, the blood flow remains good and so, it reduces the chances of getting deep vein thrombosis, says the expert. It is a blood clot in a deep vein, usually in the legs, that often gets formed during air travel.

Here are some healthy drinks you can have on a plane:

1. Water

It is important to stay hydrated, particularly when flying because dry air can cause dehydration. In addition to keeping skin hydrated and supporting bodily processes, water can assist reduce jet lag, says the expert. You should drink half a litre per hour of flying time.

2. Herbal tea

Instead of having coffee that may cause sleep issues, go for herbal tea. For instance, chamomile tea is calming, and peppermint helps in digestion. Having chamomile tea before getting some shut-eye can help improve how fast you fall asleep as well as your sleep quality, according to a 2015 study published in the Journal of Advanced Nursing. During the flight, having 1 to 2 cups of herbal tea is good enough.

3. Coconut water

It also has minerals and electrolytes, which are substances with a natural positive or negative electrical charge when dissolved in water. Our body is mostly water, so nearly every fluid and cell in our body has electrolytes. One of their main jobs is to help maintain the balance between fluids inside and outside your cells. Minerals and electrolytes get replaced in the body when we get dehydrated, so have coconut water. You can go for one or two bottles with a capacity of 330 ml.

4. Lemon juice

Smelling lemons can help get relief from nausea. They have citric acid and lemon polyphenol, so they can also help curb blood clotting. They can also help blood travel through veins smoothly. Have lemon juice once every five hours while flying.

5. Tomato juice

Tomato juice is a good way to stay hydrated. It also has potassium, folate, vitamin A and C, says Dr Patil. They can help boost your immune system and overall health. A 240 ml glass of tomato juice is what you need while flying.

6. Electrolyte drinks

Low in sugar, electrolyte drinks are particularly beneficial during long-haul flights since they help in regulation of electrolytes. Orange juice is one of the drinks that contains electrolytes, such as potassium. One or two bottles (500 to 1000 ml) can be consumed.

What not to drink on flight?

Apart from alcohol, avoid having the following drinks –

• Drinking coffee, and black tea are likely to worsen dehydration levels and disrupt natural sleep patterns due to their caffeine content.
• Sugary drinks (sodas, and sweetened fruit juices) hardly have any nutritional value. They dehydrate, and can cause a surge in blood sugar level.
• Drinks made with milk may sometimes cause indigestion.

Drinks like alcohol can make you dehydrated while flying. Instead, have healthy drinks like coconut water or simply water to stay hydrated and enjoy your flight.