You planned the interval session. You planned the meals around it. You booked the kids' pickup, answered the work email at 6 a.m. and moved the dentist appointment. Then you hit the first rep and wondered why does it feel so hard?

Your training plan counts kilometres and watts. It never counts the 47 open tabs in your head. For most of the women in my practice, that invisible load is the real limiter.

What mental load actually is

Mental load is the planning, remembering and deciding that never clocks out. It's noticing the soccer cleats are too small, knowing the permission form is due Thursday, and tracking whether anyone booked the car in for snow tires.

It's being the president, director, manager and technician for all things, all the time.

And it isn't shared evenly. In sociologist Allison Daminger's interviews with couples, women did more of this cognitive work in 26 of 32 different-sex couples, especially the anticipating and the monitoring.

Why it's physiological, not just emotional

Your body has one stress response and one recovery budget. It doesn't keep separate accounts for the board meeting, the sick parent and the tempo run. It all draws from the same pool.

The research backs this up. In a well-known study by Marcora and colleagues, people who did 90 minutes of demanding mental work before cycling reached exhaustion about 15% sooner than after watching a neutral documentary. Their hearts and muscles responded the same way. What changed was how hard the effort felt. Alex Hutchinson digs deeper into some of this in his amazing book  "Endure" - I very strongly recommend this read!

Mental fatigue doesn't directly show up on your heart rate strap.

It shows up as an "easy" run that feels like a race. Where your wearable says it was a hear effort with high heart rate but you thought it was a recovery effort.

That's the part athletes miss.

Dialing in your recovery strategies can be part of overcoming the effects of mental load - I talk more about it here.

The high-achiever trap

High-achieving women are very good at pushing through. Discipline is the skill that got you here.

Discipline can hide depletion

You keep hitting your sessions, so everything looks fine on paper. Until it doesn't: progress stalls, you snap at the people you love, or a niggle becomes an injury.

In my office, it rarely walks in labelled "mental load." Patients call it PMS. Insomnia. Brain fog. "Feeling inflamed." Those symptoms are real and worth investigating. But very often they're sitting on top of a load no body could carry forever.

Your off-season audit

The off-season is the best time to look at this. Training load is lower, so you can finally see what's left.

  1. List it. For one week, write down everything you carry: work, home, kids, family, training, appointments, and everything you remember so no one else has to.

  2. Mark what only you can do. Be honest. It's usually a shorter list than you think.

  3. Negotiate the rest. Delegate it, automate it, simplify it or drop it.

Every item you put down is energy you get back for training, recovery and the rest of your life. That's the long game: an athletic life built to last decades, not one running on empty by February.

When it's more than stress

If you lighten the load and you're still exhausted, listen to that. Persistent fatigue can have physical drivers worth testing, like low iron, thyroid changes, under-fuelling or hormone shifts.

Download my free Fatigue Testing Guide to find out which tests to ask for, and stop guessing.

— Dr. Andréa

References

• Marcora, Staiano & Manning (2009), "Mental fatigue impairs physical performance in humans," J Appl Physiol 106(3):857–64. Time to exhaustion was 640 s after mental fatigue vs 754 s in the control, about 15% shorter. Perceived effort rose, but heart and muscle responses didn't change. Small sample: 16 participants, men and women.

• Daminger (2019), "The Cognitive Dimension of Household Labor," American Sociological Review 84(4):609–33. Interview study of 35 couples. The 26-of-32 figure comes from JSTOR Daily's summary of the paper. It's qualitative, which is why the post says "in her interviews" rather than giving a population statistic.