These studies are known for excluding unhealthy people, especially those with heart conditions.
Edit: by "these studies", I mean caffeine, cigarettes/smoking, alcohol, coffee and generally any food or "health" study. If you don't know the exact make up of the test group, then I just assume it's rigged to get a certain result.
Edit: by "these studies", I mean caffeine, cigarettes/smoking, alcohol, coffee and generally any food or "health" study. If you don't know the exact make up of the test group, then I just assume it's rigged to get a certain result.