Among the truths about energy drinks are that they can cause elevated blood pressure, disruptions in normal heart function including abnormal heart rhythms, and increase the risk of serious heart problems such as arrhythmias and cardiac arrest, especially with heavy use or in combination with alcohol or intense physical activity. They often contain large amounts of caffeine and sugar, which can contribute to dehydration, increased insulin resistance, and metabolic issues, potentially raising the risk of obesity and type 2 diabetes. Energy drinks can also cause nervous system effects such as anxiety, insomnia, and, in rare cases, stroke due to cerebral blood vessel spasms. Their use among young people has been linked to increased emergency room visits due to adverse effects. Experts generally advise that while occasional consumption by healthy adults may not be harmful, regular or excessive intake poses significant health risks, particularly for those with underlying health conditions or young children and adolescents, for whom limits on caffeine intake are much lower or consumption is discouraged. These drinks can also contribute to dental erosion due to their acidity and sugar content.