During early training weeks, how are the lower and upper limits of the target heart rate zone typically adjusted?

• A. Both limits are fixed and do not change
• B. Upper limit is raised while lower limit stays the same
• C. Lower limit is higher to challenge early adaptations
• D. Lower limit is lower and upper limit is higher for progression

Answer: (D)

In the early weeks of training, you want the body to adapt gradually by increasing the training stimulus over time. The way to do this with heart-rate targets is to adjust the zone so that you can work at a higher overall intensity while still allowing some room for easier work. Lowering the threshold for entry into the zone while lifting the ceiling gives you a broader, upward-shifting zone that supports progression without pushing you too hard too soon. If the limits stayed fixed, there would be no progression; raising only one end or tightening the zone too quickly isn’t as appropriate for gradual adaptation in early training.