John’s been reviewing my last two articles on run benchmarking (Field Test then Durability Test).
In Part Two, I wrote..
Heart Rate. In the data table (below) you will see the average heart rate at the end of each hour is within 3-8 bpm of the maximum heart rate (above) from Lap 1.
The ratio of “heart rate to pace” seen in the first 20 minutes of a Green Zone workout is understated.
We need longer segments, samples after warm-up and samples at the end, to see normal heart rate response.
A rise of 5-10 bpm, with feeling staying the same, is normal.
John took the time to send along a detailed reply which I’ll share below. Hopefully, John’s tips will help reduce unforced errors.
Cardiac Drift
John’s voice continues…
The heart rate zones are best used in conjunction with pace (running), times (swimming), power (biking), and, most importantly, subjective perception (all disciplines).
Gordo’s quote (above) is explaining the phenomenon of heart rate drift and its causes. A gradual increase in heart rate indicates increased metabolic, physical (and/or psychological) stress and can be adjusted by slowing down.
Starting in a higher zone than intended, the heart rate shoots up over and above the top end of the planned zone within the first 5-10 minutes. This occurs often in racing. Despite the best intentions, starting too fast is still the most common mistake by athletes in endurance events. This applies especially to males. This is not to be confused with a higher heart rate before and during the early stages of an event due to nerves/anticipation. Checking in with subjective perception, pace, or power will help to distinguish.
Time relative to fitness. If heart rate is within the intended zone for the first 20 minutes but slowly drifts up, it suggests fatigue creeping in. The fitter we are, the longer we can maintain our heart rate in the intended zone without having to slow down.
Nutrition. The onset of depleted energy stores is indicated by higher heart rates, as the working muscles will benefit from an increased supply of oxygen and blood-borne energy substrates. Using energy drinks will also slightly increase heart rate response, especially in the Green Zone (Zone 1 and Zone 2).
Hydration. Dehydration of over 2-3% of body weight will increase the heart rate and result in a reduced performance
Onset of sickness will also result in higher-than-average heart rate when training in the Green Zone. Subjective perception should be the leading indicator here that all is not right.
‘Building’, by initially holding back and starting at the lower end of the intended heart rate zone, is the safest and most effective way to train….and race….
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