Nobody's going to challenge James Harrison to a game of "Who's Crazier?" The Steelers linebacker, famed for his brutal hits and a general willingness to turn his body into a battering ram, is taking his offseason training seriously.

But Harrison's recent workouts take the phrase, "Can you take the heat?" to a whole new level. According to video posted to his Instagram page, the linebacker recently treated himself to a workout in Arizona amid 136-degree air temperature.

Even more shocking, a reading of the artificial turf's temperature registered it at a blistering 189.5 degrees Fahrenheit.

Field temp 189.5, temp 6ft above the field 136...... Grooving on Sunday Arizona heat

A video posted by James Harrison (@jhharrison92) on

Crazy numbers, indeed. And the 37-year-old did the workout while wearing sweats and possibly a weight vest underneath. Those numbers seem far too extreme for a human to be safely working out, and that might have been the case, but some context is needed.

First of all, the artificial turf temperature reading was likely accurate -- it's very possible for turf to reach a temperature well above the air temperature, according to Turfgrass Producers International.

That's one of the downsides of playing on artificial turfs in high heat. But the rubber and synthetic materials in the turf are also poor conductors of heat, so that 189 degrees isn't radiating from the ground and reaching Harrison.

Even so, 136 degrees is an extreme temperature itself -- too extreme for exercise, many would say. The true effect of that heat depends on a number of factors, including wind speed and humidity -- drier air doesn't conduct heat as well as humid air, so in an Arizona climate, that high temperature isn't quite the problem it would be in, say, Florida.

So it's very possible Harrison was working out in the conditions he presents. How long that workout lasted is a different manner. And as for whether it was safe? Well, James Harrison hasn't made a career out of living cautiously.

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