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.
There are three main causes for primary headaches: 1  Migraine - Migraine headaches can be caused by reduced blood flow to various areas of the cerebral cortex. Symptoms of migraines include sensitivity to light and noise, nausea, vomiting and intense throbbing pain that is usually on one side of the head.