Occasionally, when the weather is bad, I go to the gym to get rid of some calories. Sometimes I run on the treadmill and sometimes I exercise on the bike. The fitness instructors advised me to buy a heart rate monitor. I shouldn’t run or cycle too fast in order to avoid muscle cramps caused by a low oxygen level. If I train at a moderate intensity I can continue for a very long time. When the weather is fine I prefer an outdoors workout however. After running one hour through the fields and in the woods I feel reborn.