Running Hydration FAQ
Frequently asked questions on running hydration.
For most runs, soft flasks carried in a vest or handheld options like the SkyFlask or Tempo are the standard setups. For long runs and ultras, add a reservoir or extra flasks, or use the UltraFlask+ Filter Cap on your flask if you are near natural water sources for safe and easy refills.
Soft flasks are better for shorter, faster runs because they are easy to refill and let you see how much you have drunk; reservoirs are better for long, self-supported efforts where you want maximum hands-free capacity. Many ultrarunners combine front-pocket flasks or handheld flasks with a reservoir in the vest.
Everyone is different but a common starting point is roughly 500ml every 45 to 60 minutes, adjusted up for heat and intensity. For most training runs, two 500ml flasks are plenty; for long runs and races, plan refills at aid stations using a fast-fill SpeedFill cap rather than carrying it all at once.
500ml soft flasks are the most popular running size and fit most standard vest front pockets; HydraPak also makes 150ml, 250ml, and 350ml flasks. Use the smaller sizes for concentrated gels and nutrition, and carry two 500ml flasks for longer races.
Rinse with warm water after each run and deep-clean with a Bottle Bright tablet, especially after using drink mix or gels. The flask and cap are also top-rack dishwasher safe. Use the HydraPak Flask Cleaning Kit for easy, deep cleaning.
