There are several things I do at start of each shift. These are important in managing the work load while ensuring that not all energy is expended before shift is over. Not to mention, there are commitments out of UPS too.
1. How long will the shift be? Check the piece count or ask supervisor how much volume is coming in that day.
2. How hot will it be?
3. Have 32 oz jug filled with water.
4. During busier times when shifts typically exceed 4 hours, pack a lunch (Rescheduling dosing for diabetes medications allows a short break under ADA to eat)
On much longer hot days, I will work at a very slow pace. If the day is short but hot, medium pace. If the day is somewhat long while cool, medium pace. On shorter days when it is cooler, I work at a fast pace. Simply throttle your work pace so not to completely wear yourself out while risking heat exhaustion and/or stroke.