The Candle Burning Guide - Center Burning Candles. Certain candles are designed to burn down the middle for different reasons, or a combination of different reasons. Candles with a unique finish, or unique burning characteristic, may burn down the middle in order to position the flame inside of the candle and illuminate from the inside out.
To find your maximum heart rate, subtract your age from 220. For example, if you are 40 years old, your maximum heart rate is 180 (that is, 220 - 40 = 180). Multiplying this by 50 percent and then 85 percent results in your target heart rate range of 90 to 153 beats per minute.
It's not normal, but it's not dangerous at your age. Your maximum heart rate at age 21 is around 200 bpm ... getting up to that is dangerous. Your exercise target rate for cardio exercise is 150 bpm ... and in theory you could do that rate for a lot of the day without problem.