Question: I’m 50 and my max heart rate is 170. I want to determine my lactate threshold so I can train at that level, but I’d rather not spend money for a lab test. Is there a simple way to determine LT? I want to ride well in the district 40K time trial. — Samuel G.
Coach Fred Matheny Replies: Lactate threshold (LT) is the highest heart rate that can be sustained before panting and pain force you to back off.
Generally, a fit rider’s LT is about 90% of max heart rate. In your case, around 153 bpm. The best way to find it — without a lab tech drawing blood from your fingertip while you pedal to exhaustion on an ergometer — is to do a 60-minute time trial. Your average heart rate for the hour should be very close to your lab-determined LT.
Remember, though, that heart rate is a poor indicator of how much power you’re generating. It’s better to learn to “read” your body so you know when you’re at the red line — the pace you can sustain for the duration of a time trial, but just barely.
Honing your perceived exertion in this way takes time and concentration, but once you learn, you won’t be tied to pre-determined (and perhaps faulty) estimates of how hard you can go.
I have written an eArticle called Equations for Cyclists that can provide a number of useful measurements, including intensity, wattage, and more, without the need for a lab test or power meter.