So no cold plunging and then sauna?

Weird. I remember hearing about how one of they key markers for longevity was exposure to heat and cold.

"Sub-Saharan Africa had the highest cold-related excess death rate"

That's an interesting choice. It conflates cold-related excess deaths in the equatorial lowlands (which struggle to ever get below 70F/20C) and the southern highlands (like Lesotho, which routinely goes below freezing in June/July). Both are sub-saharan.

Of course, that may just be a bad summary, but it puts it onto the "should probably verify the results before I trust it" pile of papers, something that's sadly growing at an ever-increasing pace.