Revision as of 15:31, 1 December 2017

At the 2014 Badwater 135 wearing a long sleeved UnderArmour HeatGear top. I'm also wearing HeatGear leggings, and I have made a face mask out of an older HeatGear top that worked really well.

I've been wearing UnderArmour HeatGear since at least 2009, and it's still the best option for most situations. I've run in HeatGear in a wide variety of conditions, from the intense dry heat of Death Valley during 2014 Badwater 135 to the oppressive heat and humidity of the 2010 Keys 100. HeatGear has a number of benefits.

• It's extremely thin, so it offers very little insulation. I've not found any top that is as thin. This thinness also allows sweat to spread out very rapidly, maximizing the cooling effect.
• There are a range of colors including white. All too often, runners underestimate the impact of the heat from the sun on their running performance. While this is an obvious issue on a hot summers day, it's also a significant factor in much milder conditions. For more on how heat impacts runners, see Impact of Heat on Marathon Performance.
• The compression fit helps prevent chafing, something that can be an issue on marathons, and a major problem during longer runs. While the construction is not seamless, I've never had any issues, even with my skin condition, and after long ultras.
• The material offers good UV protection, and the compression tops are available in long sleeves. Protecting your skin from the sun not only has long-term health implications, but sunburn can cause problems during an ultramarathon, as sunburned skin cannot regulate your temperature effectively.
• I've found that HeatGear is my preferred base layer in colder conditions. While you might expect a thicker base layer to be more effective, I've consistently preferred HeatGear over UA's ColdGear or a number of other warmer base layers that I've tried. The big advantage of HeatGear is that it doesn't hold much sweat. This can be a big deal in winter when you get a little too warm and start to sweat. At that point you'll need to shed some insulation layers, or open some zippers. If you're wearing a thicker base layer, it will take far longer to dry out, and you end up in the awkward situation of too warm or too cold. I found the HeatGear will try relatively quickly, making it far easier to regulate my temperature.
• It's surprisingly hard wearing, and I've had tops that have lasted a good number of years.

There are a few situations where HeatGear is not the best choice.

• The main downside I've found to HeatGear is that there is no odor resistance. This isn't too much of a problem while training at home or racing, but I found it a major pain if I'm traveling and can't wash my running gear regularly. I love merino wool, which has good natural odor resistance, but it's expensive, fragile, and I've yet to find a compression top made of merino wool. For travel, the best option I've found so far for odor resistance is XOSKIN.
• When it's hot and humid enough that you are dripping with sweat and soaking through all clothing, it doesn't matter so much that the thin material spreads out the sweat. HeatGear is still better than any other clothing I found because its thinness offers less insulation than you'd get with something thicker. However, if you're out of the sun and sweating profusely, you may be better off with bare skin. This is not a huge difference, but running at night in intense heat and humidity, I sometimes prefer bare skin to HeatGear.
• A thin white top that's wet does tend to be quite revealing, so this may be a factor.

Black and White

I performed this simple test of how black and white materials behave in the sun. I placed a black and a white HeatGear top over a cardboard box in a full sun. I dampened the middle of each with 2 tablespoons of water and left them for about 15 minutes. The air temperature was about 66f/19c. this test is not realistic, as the temperature of the shirts on their own will rise far higher than when they are worn. However, I believe it gives a good indication of how important it is to have light rather than dark clothing when you're running.

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  The test setup, with the white top on the left and the black top on the right.

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  Where the black top is dry, the temperature is 122f/50c

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  Where the black top is wet, the temperature is 88f/31c

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  Where the white top is dry, the temperature is 105f/41c

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  Where the white top is wet, the temperature is 72f/22c