With the heat and humidity of summer quickly approaching, and the race season well under way, I’ve had some athletes and clients ask me why their heart rate tends to climb, even when their perceived effort remains the same. This is commonly known as ‘Cardiac Drift’ or the slightly more technical name, ‘Aerobic Decoupling’. Whether you are a seasoned athlete or an ‘average Joe or Jill’ looking to get outside and enjoy some exercise, it’s helpful to know what this sensation means and how we can avoid it.
Let me say upfront I’m not a medical professional. But I’ve seen this happen a lot with athletes (and non-runners/triathletes) over the years. Essentially, cardiac drift is characterized by a higher heart rate than warranted for a specific work load. Typically we see this in runners and cyclists. For example, a runner might be doing a 90 minute, steady effort long run, yet 45 min into the effort, the heart rate begins to slowly climb from 140 bpm to nearly 170 bpm by the end of 90 minutes. While some drift may be normal (5-10 bpm) over the course of the effort, excessive cardiac drift likely has some specific causes. In my experience in working with athletes, there’s a few things that can be causing the heart rate to elevate WITHOUT a rise in effort:
Hopefully these tips shed some light on what happens when the HR gets too high too quickly, and FAILS to match the intensity of the workload. Again, some drift is normal, but If this happens to you on a regular basis and is excessive (more than 5-10 bpm), reach out to me directly and let’s see if we can determine the specific cause of your aerobic decoupling.