It's getting warmer, and suddenly exercise seems harder, even if you're working indoors. For a few weeks around this time, you'll wonder where your stamina went if you exercise regularly and live in a state like Michigan with pronounced seasons. Worry not, your body is just adjusting to the temperature change. Make sure to get lots of water during this time, especially if you are outside and active. 64 ounces per day is a reasonable minimum! In the meantime, enjoy the weather!