Cardiovascular drift
Paper details:
Re-write paper below for advanced exercise physiology …
Why does a cardiovascular athlete, such as former Tour de France Champion Chris From, have to be aware of the concept of cardiovascular drift? Explain in great detail to this athlete what cardiovascular drift is and also identify the factors that will affect his cardiovascular drift during a long cycling training ride.
The human cardiovascular system is responsible for delivering a continuous supply of oxygen and nutrients to active muscles, which maintains a high level of energy transfer, while also removing metabolites. Compared to static or dynamic resistance exercise, aerobic exercise demands an increase in energy and therefore an increase in oxygen hence aerobic exercise. The bodies’ oxygen requirements are mainly dependent upon exercise intensity and duration. Anyone who has ever exercised with a heart-rate monitor knows what happens over the course of a training session maintaining a steady intensity level results in an increased heart rate HR.
HR rises over the course of a workout because as the body tires it has to work harder to maintain the same power output. This is true of any endurance activity: walking, running, cycling, rowing, and others. Upon careful evaluation of our other day to day activities we would also find this same phenomenon occurring which is why many people feel fatigued at day’s end.
This phenomenon can also be measured in terms of power output. Power-focused exercise is a traditional approach, one solidified during the running boom of the 1970s.
Other power-based formats include, pace minutes per mile or kilometer, speed miles or kilometers per hour, wattage output and others. This approach has obvious benefits, such as facilitating the tracking of caloric and power output. However, it also has important drawbacks. In a workout in which power output remains steady, the observed rise in HR is known as cardiac drift.
This is easily measured during exercise. However, it is usually treated as a casual observation that holds little value, and at worst, as evidence that heart rate is an unhelpful biometric.
Cardiovascular drift refers to the increase in heart rate that occurs during prolonged endurance exercise with little or no change in workload.
During steady state aerobic exercise, heart rate should reflect the intensity of the work being performed. If intensity workload remains constant, heart rate should remain constant as well. With prolonged exercise, however, it is common to see heart rate “drift” upward during the workout, even with no increase in workout. Sometimes the increases can be significant.
Cardiovascular drift is mostly caused by increased body core temperature. This increases heart rate, but decreases stroke volume so that cardiac output and oxygen uptake remain the same.
Both causes of cardiovascular drift will be more pronounced when exercising under thermal stress, hot room and high humidity.
The effect can be blunted somewhat by ingesting sufficient fluid during the workout. Don’t be a slave to your heart-rate monitor numbers. Rather, use your heart rate as a tool to help you learn your efforts and paces and as a guide to help get you started on the right track. One way to accomplish this is to learn to use breathing rhythm as a way to intuitively assess your intensity.
You won’t be perfect with this method at first, so wear the heart-rate monitor and use it the first 10-15 minutes of your run to get on track. Then, cover it up and practice running by feel.
Look at the data only after you’re done running and compare your breathing rhythm and the effort you felt to the heart-rate numbers. By understanding the underlying concepts behind heart-rate monitors and other training gadgets, you can learn to better listen to your body and apply these tools to help you tracgoin smarter in the long-term.
