Since the beginning of lockdown I (like the rest of the world it seems!) decided to use my daily exercise to run and walk loads. This has meant upping my frequency, duration and intensity of my runs.
Up until lockdown I had been running 5k three to four times a week at my usual pace, not too fast, not too slow, can’t quite breathe comfortably, but not (so i thought) overdoing it….. basically the way i had always trained at baseline, with the odd few strides here and there, and with the inescapable hills that come with living in North London.
Suddenly I had upped the frequency to six runs, with one at 10k. Intensity had also increased to two of my runs mainly at threshold.
Three weeks in, and my pace hadn’t improved. I didn’t feel i was getting fitter, and if anything was feeling more fatigued in general, despite sleeping loads. I expected the fatigue, after all i’m not the spring chicken i once was, but I was struggling with keeping up my normal pace. Even an extra rest day wasn’t working.
Enter a running friend of mine who suggested i actually use some of the features on my Garmin to help me out. Specifically Heart Rate Zones.
What can i say? Four weeks later and I’m feeling fitter than ever, faster, and the fatigue is a distant memory.
This is how it went………
It seems like the most accurate way of looking at your zones, without expensive equipment in a lab, is to use the Heart Rate Reserve concept, also called the Karvonen Method.
For this you need to find out firstly your maximum heart rate. Using the 220-age formula my MHR would have been 166, since i am 54 years old. However, looking at previous 5k park runs where i was running all out for the last 500 metres I was regularly exceeding that figure! So I took the highest figure from the last year, and added 1, which made 174 beats per minute. Far higher than the age equation!
Next my Garmin was measuring my resting heart rate overnight, which was 49. So my heart rate reserve was 125.
Armed with this information Garmin neatly divides your heart rate reserve into 5 zones, and a little research on the net allowed me to determine the approximate proportion that I should spend in each zone during training. I’m sure that training for a race would alter the proportions, particularly in the time spent in aerobic and threshold, but this is good for now since i’m just building a base.
- Zone 1 Warm up (20% of training) = 50-60% of Maximum Heart Rate (MHR)
- Zone 2 Easy Training (40% of training) = 60-70% of MHR
- Zone 3 Aerobic Training (25% of training) = 70-80% of MHR
- Zone 4 Threshold Training (10% of training) = 80-90% of MHR
- Zone 5 Interval Training (5% of training) = 90-100% of MHR
So on a typical 20 mile week I’ve been in zone one for 4 miles, zone 2 for 8 miles, zone 3 for 5 miles, zone 4 for 2 miles, and zone 5 for 1 mile.
I’ve been making sure that I follow an interval training day with an easy run day, using common sense, and I’ve found that my fitness has improved. The thing that has been difficult to stomach, but I’m sure is the crucial element to good recovery, is that I have spent my running life for years too close to threshold all the time! So it has been a leap of faith to slow down…… in order to speed up!
…….. and at last I feel that my investment in a Garmin has been worthwhile!
Gavin's Blog 