I’ve been taking close to daily lactate readings for the past month and a half.  In addition to thoroughly perforating my ring finger and keeping Nova Pharmaceuticals in business, this has both baffled and entertained me as I tried to understand how to best implement a polarized training plan using lactate measurements to manage steady state intensity.

I’ve previously posted this scatter plot of lactate readings*

Which shows essentially no correlation between HR and lactate.  Over the past couple of weeks, I thought I was starting to see some relationship between lactate and HR readings and the day of the week, so it was time to bust out excel and see what i could find.

I follow a reasonably consistent workout schedule.

• Sunday:  Usually rest, but last month I was doing 10K just to bank the meters for a C2 challenge.  Definitely the lightest trainning day in any case
• Monday:  ~80′ of steady state at target training power
• Tuesday: ~80′ of steady state at target training power
• Wednesday: 20′ lactate test at target power, and then an intense interval session
• Thursday: ~80′ of steady state at target training power
• Friday: ~80′ of steady state at target training power
• Saturday: 20′ lactate test at target power, then a middle distance threshold workout (10K,30min, 6K, 5K)

Another thing to note:  Saturday and Sunday sessions are at home on a static erg, during the week, most days are on slides.  The airflow and temperature at home are better too.

Here’s the HR and lactate data sliced by day of the week.

First things first.  Thee is still a lot of variation in the data when analyzed by day of the week.  But looking at the data for lactate you can see a repeatable variation by days of the week.  The effect is less pronounced with HR, but interestingly, it is shows a different day to day change.

So, starting with Sunday.  I am on a static erg, in a cool environment, in addition to that, I am coming off a hard workout the day before.  Both HR and lactate are low.  Average HR is reasonably consistent for Monday, Tuesday, Thursday and Friday.

So, what’s deal with Wednesday?  I theorize that by Wednesday my lactates are low and my HR is high because I of the accumulated workload on Monday and Tuesday, so I have less glycogen available to create lactate.  Since my Wednesday workout is shorter but more intense, it actually ends up being fewer overall meters (and calories) than a steady state session.  This means that I actually have more glycogen available on Thursday morning for steady state, so, lactates are up a bit.

It’s all quite confusing, but I think it makes sense to use a consistent. specific session during the week to set training power, and if you believe that the most important consideration for setting the optimal training power is to make sure that it consistently yields less than 2.0mmol/l in all sessions, that the session you use to test power setting should be one where you are well fueled and rested.  For me that’s Monday.

* Note: Lactate and heart rate readings are taken at the end of a 20′ steady state piece at constant power.  Lactate readings are taken at the conclusion of the piece.  HR is the average HR for the last 5 minutes of the piece.  Power is changed on a weekly basis (or sometime more frequently) to attempt to maintain lactate levels between 1.5 and 2.0 for all steady state rows.