Whether you’re training for your next Spartan Super, Beast, or Ultra you know staying hydrated is essential. In fact, your performance in the race is directly linked to it. “Proper hydration can be the difference between first and second place in a race,” says Naresh Rao, D.O., F.A.O.A.S.M., partner at Sports Medicine at Chelsea in New York, NY, and author of Step Up Your Game. “Our bloodstream is mostly made of water, carrying glucose to muscles and carrying away waste.  Dehydration can be insidious, and is a common reason for fatigue, muscle cramps, and poor performance.” To get enough fluids, consider investing in a running hydration pack that will help you fuel up and feel your best. 

The amount of water you need to train and compete at your peak level is, of course, different for every athlete. In general, Dr. Rao recommends drinking 16 ounces of water two to three hours before a race and eight ounces 15 minutes before running off the starting line. While racing, aim to drink four ounces of fluid every 15 to 20 minutes — approximately two to three gulps. After competing, you should drink 16 to 20 ounces of fluid for every pound lost. (This handy urine chart from the National Collegiate Athletic Association (NCAA) will help you quickly determine if you’re properly hydrated or if you need more fluids.) “You can carry more [water] as a reserve in case you take longer to finish the race, but if you plan appropriately the extra amount should be negligible,” adds Dr. Rao.

Related: Hot Weather Race-Day Tips

Here, the best running hydration packs to keep you safely nourished during training, and on race day. Plus, they have some nice bells and whistles that'll come handy on the course. 

1. Osprey Katari 3 Hydration Pack – 2.5 Liters

Perfect for a Spartan Super, you can sip without stopping, as the pack’s bite valve straw lets you drink hands-free. This pack has an attachment for a blinker light for early morning or late night training, as well as roomy side pockets to stash electrolyte packets and snacks to help you stay fueled and prevent muscle cramping.

$65; rei.com

2. Salomon Advanced Skin 5 Set Hydration Vest

This vest uses two soft flasks stashed in the front of the vest which are held snug by the design, reducing bouncing around as you run. The flasks hold up to five liters of liquid. Need more? There’s also an option to slip a bladder into a dedicated spot on the back of the vest. With plenty of pockets, this vest holds ample amounts of snacks and gear but is extremely lightweight and breathable.

$135; rei.com

3. UltrAspire Momentum Hydration Vest

The functionality of this vest is perfect for athletes who need a large volume of liquid or for those who prefer a vest over a belt. Holding up to five liters easily, you can stash liquid in the front, back, or both (if needed) as the front has room for two soft flasks and the back for bottles. Customizable, it's a great starter vest for Spartans racing all types of races. Bonus: It’s a nice middle-of-the-road option when it comes to price.

$80; rei.com

4. CamelBak M.U.L.E LR 15 Hydration Pack

This pack has easy to reach pockets, so you never have to take it off when racing. The hydration tube delivers 20% more water in each swig, and a lever opens and closes it, helping prevent leaks. It can carry up to three liters of liquid and athletes love the placement of the water bladder in this pack, which makes weight distribution seamless and keeps the load you’re carrying light.

$140; amazon.com

5. Unigear Tactical Hydration Pack Backpack 900D

No obstacle is a match for this pack. Made with 900 Denier Polyester and PVC lining it handles more than just a little wear and tear without being overly bulky. Holding over two liters, the bladder in this pack has a wide mouth, which makes it great for icing up your liquid to keep it extra cold while you race. Plus, with a price tag like this you can beat it up on the obstacles, guilt-free. 

$33; amazon.com