There doesn't seem to be a continuous lactate sensor on the market.
They exist, a simple search will turn up a variety (how well they work is a different question). But see my sibling comment, they're banned from cycling competition.
To follow-up, "commercially available" products from a simple search appear to all be vaporware. I did see that cyclists have been estimating lactate thresholds through breathing rate/expiration volume measurements
They exist, a simple search will turn up a variety (how well they work is a different question). But see my sibling comment, they're banned from cycling competition.