From the Guidelines
Consuming 800mg of caffeine daily poses significant health risks and is not recommended. This amount far exceeds the suggested safe limit of 400mg per day for healthy adults, as stated by the Dietary Guidelines for America 1. At this high dose, you may experience severe anxiety, insomnia, digestive issues, muscle tremors, rapid heart rate, and elevated blood pressure. Some people might develop heart palpitations, chest pain, or irregular heartbeats.
The potential health risks associated with high caffeine intake include:
- Severe anxiety and agitation
- Insomnia and sleep disturbances
- Digestive issues, such as diarrhea and stomach upset
- Muscle tremors and twitching
- Rapid heart rate and elevated blood pressure
- Heart palpitations, chest pain, or irregular heartbeats
- Headaches and dizziness
- Dehydration and electrolyte imbalances
According to a systematic review 1, high caffeine intakes (e.g., >5 mg · kg body weight–1 · d–1) were associated with an increased risk of anxiety and withdrawal symptoms in children. Additionally, the European Food Safety Authority advised that pregnant women should limit caffeine intake to 200 mg/d 1.
It is essential to note that people with certain health conditions, such as heart problems, anxiety disorders, high blood pressure, or gastroesophageal reflux disease, face even greater risks when consuming high amounts of caffeine 1. Caffeine at this level can also interact dangerously with medications, including certain antibiotics, antidepressants, and asthma medications.
If you're currently consuming this much caffeine, it's advisable to reduce your intake gradually rather than stopping suddenly to avoid withdrawal symptoms like severe headaches and irritability 1. The safest approach is to limit daily caffeine intake to 400mg or less, as recommended by the FDA.
From the FDA Drug Label
Serious toxicity has been associated with serum levels greater than 50 mg/L Signs and symptoms reported in the literature after caffeine overdose in preterm infants include fever, tachypnea, jitteriness, insomnia, fine tremor of the extremities, hypertonia, opisthotonos, tonic-clonic movements, nonpurposeful jaw and lip movements, vomiting, hyperglycemia, elevated blood urea nitrogen, and elevated total leukocyte concentration Seizures have also been reported in cases of overdose.
The health risks of consuming 800mg of caffeine include serious toxicity, with possible signs and symptoms such as:
- Fever
- Tachypnea
- Jitteriness
- Insomnia
- Fine tremor of the extremities
- Hypertonia
- Opisthotonos
- Tonic-clonic movements
- Nonpurposeful jaw and lip movements
- Vomiting
- Hyperglycemia
- Elevated blood urea nitrogen
- Elevated total leukocyte concentration
- Seizures 2
From the Research
Health Risks of Consuming 800mg of Caffeine
- The consumption of 800mg of caffeine can lead to severe health risks, including arrhythmias, hypertension, and respiratory failure 3.
- However, it is worth noting that the majority of studies suggest that moderate caffeine intake, defined as up to 400mg per day, is not associated with adverse effects in healthy adults 4, 5.
- Excessive caffeine consumption, on the other hand, can cause negative health consequences such as psychomotor agitation, insomnia, headache, and gastrointestinal complaints 5.
- Fatal caffeine overdoses are relatively rare, but can occur with the ingestion of large quantities of the drug, typically in excess of 5g 6.
- Moderate ingestion of caffeine does not increase the frequency or severity of cardiac arrhythmias in normal persons, patients with ischemic heart disease, or those with pre-existing serious ventricular ectopy 7.
Comparison to Recommended Daily Intake
- The recommended daily intake of caffeine is up to 400mg per day, which is equivalent to around 5 cups of coffee 4, 5.
- Consuming 800mg of caffeine would exceed this recommended daily intake, and may lead to adverse health effects.
- It is essential to be aware of the caffeine content in various products, including coffee, tea, energy drinks, and food supplements, to avoid excessive consumption 5.
Special Considerations
- Pregnant women, children, and adolescents should limit their daily caffeine consumption due to the potential risks to their health 5.
- Smokers and individuals with mental illnesses may consume more caffeine than non-smokers and those without mental illnesses, which can increase their risk of adverse health effects 5.