9-ThinkstockPhotos-483267026.jpg

Thinkstock

Increased levels of thyroxine released from the thyroid gland stimulate the heart to beat more quickly and more strongly, producing a fast heart rate (tachycardia) or palpitations, according to the Thyroid Foundation of Canada. Your heart beats very fast and it may skip a beat. You will probably experience palpitations in your throat and chest even when you’re resting. Increased levels of thyroxine released from the thyroid gland stimulate the heart to beat more quickly and more strongly. People whose gland is underactive may notice slower than usual heart rate.