Flexible Economy is a new enhanced Economy service operating on a single cabin aircraft for customers on our shorthaul network flying to and from London Heathrow.
Although caffeine is generally safe and well tolerated, it can cause side effects when ingested in large doses. Additionally, regular caffeine use can cause dependency, resulting in withdrawal symptoms when caffeine is not consumed. Headaches can be a symptom of either too much caffeine or too little.
Understand why caffeine withdrawal causes headaches. Caffeine is a substance known as a vaso-constrictor, this means that is decreases the diameter of your veins. 1  When caffeine runs through the blood vessels, it causes the veins to constrict or narrow. 2  When you stop taking caffeine, the veins that were constantly constricted will open up.