Caffeine alerts. It blocks adenosine, a tired-making brain chemical. It also triggers the release of adrenaline, the "fight-or-flight" hormone.
Anxiety
Caffeine may delay sleep onset. It may reduce sleep time, especially for the elderly.
Insomnia
Small to moderate doses of coffee can enhance gastrointestinal motility, but more can cause loose stools or GERD. Switching from coffee to tea may help.
Digestive Issues
This is a big dose of caffeine to ingest in a short time, especially for someone not used to it or sensitive to its effects. For rhabdomyolysis prevention,
Muscle Breakdown
Caffeine addicts who go without it for several hours may experience psychological or bodily withdrawal.
Addiction
Caffeine raises blood pressure in high doses, before exercise, and in infrequent users. This impact may be transient, so be careful.
High BP
Caffeine can speed up your heartbeat. Young people who drank energy drinks with high caffeine levels developed atrial fibrillation.
Rapid Heart Rate
Caffeinated coffee, tea, and soda improve energy. After the caffeine wears off, they can cause rebound weariness.