There actually should be a change of heart rate because sense your body would contain all of this energy, your heart rate would be pounding pretty fast at a constant speed until you feel the need to rest from your hyperness of energy.
It should be around (90-100%) of the MAX heart rate that it should be reaching. Any higher, and you could have some health problems. Therefore, your correct answer would be the very (first option).
When running or cycling very fast our body turns to anaerobic metabolism to get enough energy. Anaerobic metabolism produces lactic acid, which can build up in the muscles to the point where we "feel the burn." The anaerobic zone of exercise intensity is 80% to 90% of our maximum heart rate but the heart beat per minute varies with time as the person gets older. 15% of our calories burnt in this zone are fats, 1% are proteins and 85% are carbohydrates.
