Hold up. I'm not super experienced in reading studies, but I can read.

1. At best this is correlation. HRV increasing for these men doesn't mean a high HRV is required to be good at chess.

2. Sample size of 16... And only male.

HRV was reduced in participants who achieved worse results. This could indicate the possibility of HRV predicting cognitive performance

If reduced HRV means lower cognitive performance and women have, on average, lower HRV, you're saying women are less smart. At least in chess. I think that's bullshit and this study isn't incorporating enough/the correct data to show anything you're stating.

But here is one: https://www.sciencedirect.com/science/article/abs/pii/S0149763411002077 that links HRV with stress response

And another: https://www.sciencedirect.com/science/article/abs/pii/S0149763419310292 That shows women's HRV responds less severely to stress.

Both meta-analysis, not a single data point.

So maybe men are just shit at dealing with stress and that's why their brains go haywire during competition. But it's so gracious of you being so kind to women and giving them a space where they can play among equals on a "MORE level playing field."

By your logic, they should just be testing people's HRV and ranking them that way so they all are on even ground. Give those dummy men a MORE level playing field.