Acid reflux, stomach irritation, and heartburn can result from black coffee's strong acidity, especially in sensitive stomachs.
Due to its stimulating effect, black coffee, especially in the afternoon and evening, can alter sleep cycles and cause insomnia.
Black coffee's caffeine can produce a rapid heartbeat or palpitations, especially in sensitive people or those with cardiac issues.
Anxiety and jitteriness: Black coffee's caffeine can cause anxiety and restlessness.
Black coffee's diuretic qualities can increase urination, causing dehydration if water intake is low.
Dependency and withdrawal: Regular black coffee drinking can cause caffeine withdrawal symptoms as headaches
High-acid black coffee may cause stomach ulcers or gastritis in some people, causing pain and suffering.
Black coffee's high caffeine content may affect calcium absorption, affecting bone health if not balanced with calcium in the diet.