You want to be mainly in the Normal rhythm (blue). Scientific name is Sinus. Arrythmias can include tachycardia and others. I try and stay in the 90% blue during daily routines. Exertion and exercise will push the heart rate up thus causing ‘other’ rythmnsThe arrythmia you want to avoid is atrial fibrillation which can cause a stroke. If you are worried from a high percent of arrythmias see your cardiologist.