This might be a simplistic analogy of what happens when you exercise to exhaustion, but let's assume your body can produce only so many heartbeats before it says "I'm done," dropping considerably off the pace.
If you focus your race strategy on the last few miles of the run, where this is most likely to occur, it makes sense to take advantage of every opportunity during the race to "bank heartbeats" so you can spend them in the most difficult part of the race.
Our natural tendency is to apply more power to the pedals when we meet resistance in the form of a hill or headwind. This can be dangerous, as you may be riding outside of your capabilities.
Shift to an easier gear and continue to ride at your target heart rate and within your capabilities. The people passing you are most likely not riding within theirs. You will see them later.
Our other natural tendency is to back off on the power when resistance decreases, such as when riding with a tailwind. Two things you can do here:
1. Ride at the same HR as if with no wind and go much faster.
2. Bank heartbeats. Decide that for your race, 28 mph for 8 miles is as good as 32 mph. Soft-pedal, get your HR down and put money in the bank to spend on the run.
Rich Strauss has qualified for the 2003 Ironman World Championships and specializes in training Ironman athletes. He is a USAT and USAC certified coach, as well as a former Marine Corps officer. To receive weekly training tips and his monthly newsletter, The Brick, please visit www.cruciblefitness.com.