Old Navy Long-Sleeve Breathe ON Slub-Knit T-Shirt A moisture-wicking Old Navy Long-Sleeve Breathe ON Slub-Knit T-Shirt ($20) can easily be your winter workout essential — and luckily there are six colours to choose so you can work in a full rotation. Image Source: oldnavy.gap.com Old Navy Long-Sleeve Breathe ON Slub-Knit T-Shirt $20 from oldnavy.gap.com Buy Now