Calculating Heart Rate Zones

If you don’t train with a power meter, you will want to use your heart rate monitor as a measure of your intensity. To calculate your training zones, you will need to know your maximum heart rate (HRmax) and resting heart rate (HRrest). You can obtain your resting heart rate by checking your pulse each morning for three to five days and taking an average. Your maximum can be calculated by subtracting your age from 220. There are other methods, but this is the easiest place to start. You could also record your heart rate (HR) during a training session in which you perform some difficult intervals and take note of your highest heart rate. This may be an indicator of your lactate threshold. You could assume that this heart rate would be about 85% of your maximum thereby allowing you to calculate a maximum heart rate. Once you have your resting and maximum heart rate, you will use the following formula to calculate your target heart rate as a %:
HRmax – HRrest = HRreserve
(HRreserve x _target%_) + HRrest = Target HR

Example:
HRmax of 180, HRrest of 50
Target zone: 50%
180-50 = 130 beats per minute (bpm)
(130x.5) + 50=115 target HR for 50%
60% = 128 bpm
70% = 141 bpm
80% = 154 bpm
90% = 167 bpm
Your zones would then be:
1 - 115 to 127, 2 - 128 to 140, 3 - 141 to 153, 4 - 154 to 166, 5 - 167+

A less complicated formula that I use personally and for riders that I’m coaching based on a % of your HRmax:
Zone 1 - 60-68% warm-up, recovery ride
Zone 2 - 68-76%
Zone 3 - 76-84% aerobic rides of several hours
Zone 4 - 84-91% lactate threshold effort; efforts of 5 minutes to one hour
Zone 5 - 91%+ short, powerful efforts of 10 seconds to 1 to 3 minutes

Lactate Zones

If you know your HR at Lactate Threshold (this would be an effort that you could hold for up to an hour, usually about 85% of your max, up to 90-93% for the elite athlete), this is the most accurate method to determine training zones
(1) 65 - 75% of lactate Hr
(2) 75 - 85%
(3) 85 - 95%
(4) 95 - 105%
(5) 105%+

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Please note that zones ranges can vary for each individual and that the accuracy of the above method is contingent upon accurate HRmax and MRrest values, and these can change depending on your training and health.

Wattage Zones based 2x8 minute field test average

100=field test average

Power Intervals: 100%+
Time Trial: 95-100%
Steady State:85-90%
Tempo: 80-84%
Endurance Miles: 45-75%
Recover miles: <45%

Field Test Conversions for Indoor/Outdoor Wattage Zones

	Indoor	Outdoor
Pi	90+	100+
TT	84-90	95-100
SS	76-80	85-95
T	70-75	80-85
EM	40-66	45-75

Critical power conversions:

Do (1) 3 minute all out
Do (1) 20 minute all out
3 min avg watts x 180 seconds= joules for 3 minute
20 min avg watts x 1200 seconds= joules for 20 minute
Take difference in joules and divide by difference in seconds to get FTP

Example:
3 min x 390= 70,200
20 min x 330=396,000
396,000-70,200=325,800 divide by 1200-180=319.41