There should be no initial threshold to exercise. There should be no need to create motivation through willpower. The body generates motivation automatically when the level of exertion is precisely right.

The best tool for adjusting physical exertion is the GPS heart rate monitor, but you have to interpret the raw data of the monitor with solid knowledge of physiology and sensitive self-awareness.

This book combines the three critical elements. When brains, feelings and muscles work together, exercise will always feel enjoyable, so you want to do more of it.

The principles of smart heart rate control apply to everybody. The beginners can get out of the vicious circle of boom and bust. The enthusiasts can replace willpower with brainpower. The athletes can significantly lower their risk of overexertion.

"The GPS heart rate monitor is an important tool for athletes and beginners alike. When you learn how to interpret the monitor correctly, you will use your physical resources in an optimal way." Marathoner Leena Puotiniemi