First Lactate Scout Measurements

Finally, I’ve got my Lactate Scout Sport — and, unlike most people, I actually started by reading the manual 😄
(Good thing I did: the strip code had to be changed in the device first.)

As it turns out, measuring lactate isn’t that simple.
My first test was a mess: the blood drop was too small, I pressed the strip too hard, and the result came back 4.0 mmol/L at rest, which made no sense.
A moment later, more blood started flowing (the 2.4 mm / 21G lancets are no joke).

Then I went for a run:

• Easy run: ~5:40 / km, upper Z2 → 3.8 mmol/L.
• Tempo segment: 3.2 km @ 4:42 / km, avg HR 171 → 177 bpm at the end → 4.3 mmol/L.

Testing blood mid-run was a hassle:
blood flowed much faster with high HR, I ended up with a hand literally covered in blood, strips kept throwing errors, and each test took over a minute.

Three hours after the session, lactate was 0.9 mmol/L at rest,
and the next morning (fasted) 1.2 mmol/L.

Takeaway

Garmin’s LTHR estimate (177 bpm at ~4:42 / km) seems reasonably accurate.
But the key insight is that what my watch calls “easy” may not actually be easy for my body —
my real Z2 could be sitting in the gray zone, with lactate already between 2–3 mmol/L.