It is a truth of pretty much any type of exercise that you're going to vacillate between punishing your body and giving it a little TLC. As runners, we often strive to push our limits by going a little farther or a little faster. Many of us also crave that boost of daily endorphins that only comes from watching the world fly by as we pound the pavement at top speed.

Unfortunately, our bodies need downtime, too, in order to recover from the stresses we place on them. Otherwise injuries are bound to occur. At the very least, you're going to feel like you're pulling a lead sled when you hit the trail if you don't allow your body adequate rest. At worst, you could inflict real damage that leaves you unable to run for a lot longer than if you had simply interspersed some rest days with your running.

In truth, there are several factors involved in keeping your body fit and healthy. Here are a few rest and recovery basics that will help to keep you on track and trucking down the trail.

Schedule in Rest Days

Our bodies were designed for movement and many of us love to challenge ourselves. However, running puts a lot of stress on bones, joints, and the whole body. We weren't necessarily meant to run miles and miles on a daily basis, and eventually your body will start to rebel with aches, pains, and injury.

If you try to push through, eventually you could end up doing serious harm. It's important to listen to the signals your body sends so you know when you're dealing with fatigue that you can overcome and when you're skirting the edge of injury.

That said, you may never get to this point if you practice a simple preventive technique: schedule in rest days and always make sure you get you get plenty of sleep. When you give your body adequate time to rest and repair the damage caused by physical exertion, you're much more likely to remain healthy and continue on your path. Even on the "Advanced" track of our 30 Day Challenge we have rest days scheduled...you should too.

Vary Terrain

Actress Mae West famously quipped, "Too much of a good thing can be wonderful." Unfortunately, this is rarely true, and it definitely doesn't apply to running. When you run too much, your body is going to start protesting.

One way to deliver a bit of respite is to vary the courses you choose in order to allow certain muscles some rest while you put others to the test. Instead of running the same flat course every day, challenge yourself with hilly terrain. Or throw in a trail run to slow you down and test different skills. You'll still need rest days, but this could also help you avoid some of the persistent aches and pains that often plague runners.

Watch Your Diet

When you're testing your body's limits, the least you can do is reward it with the right fuel for exertion and recovery. Your body will burn through carbs for energy when you run, but protein provides the building blocks needed to repair damaged muscle, and if you run a lot, you're definitely doing some damage.

If you're a serious runner, it's probably best to speak with a nutritionist to ensure you're choosing the right diet to meet your body's needs. Otherwise you may not be adequately recovering from your exertions and injuries could result.

Hydrate

There's no way to overstate how important it is to hydrate your body when you run. You're going to sweat, depleting your body of water and nutrients. Proper hydration is essential to facilitating the transport of fluids throughout the body. Without it, every part of your body will have to work harder to perform on demand. In short, you're going to feel it when you run, as well as later on.

Warm Up, Cool Down

Obvious, right? What's amazing is that there are still people debating the merits of warm ups and cool downs. You can determine for yourself whether cold stretching is necessary before exercise - many people now prefer a gentler version of the activity in question. This could entail a few minutes of walking and then light jogging before you start your run.

When you're finished, you want your body to remain warm for a while, so slow your roll when you finish running with a short walk. Always take the time to stretch muscles while you're already loose in order to remain limber.