If you're tired of the same workout, or just not seeing the same results as you used to, it's probably time to change things up. Here are five signs that it's time to change your routine.

1. No Motivation
Your iPod is fully loaded. You spent an hour (or more if you're like me) on iTunes coordinating a compilation of music that should keep you moving infinitely. One song into your workout you lose steam and decide to call it a day.

Maybe you're having an off day, or maybe you've got a lot on your mind. Regardless, you need a good dose of perseverance and a change of environment.  Do something different, but keep doing something. Your motivation will spring back before you know it. Remember to keep your eye on the prize (the reason you workout).

2. Over-Stressed
One of the greatest benefits of exercise is stress reduction. These days, however, after you wrap up a hard workout you're more "stressed" than when you started.

This applies mostly to people who have been under a great amount of stress for a long period of time, not to those of us who start a workout annoyed that we got a parking ticket because we were 30 seconds too late to plug the meter. Ongoing stress related to work, family and finances, etc.,  can tax you both mentally and physically. Compounding this type of stress with a high impact, or overly-vigorous workout could make things worse. Until stress feels manageable, try other forms of fitness, including yoga, pilates, walking or Qigong. Your body will thank you.

3. Over-Trained
When you started your new "routine" months ago, your heart rate would climb and you'd finish your workout completely invigorated. When you finish your workout today, you don't get a buzz anymore - and lack the energy you used have.

Overtraining syndrome can happen to anyone, but usually hits athletes-in-training the hardest. Our bodies recover and improve when we rest. The "rest period" is crucial and should not be overlooked, or underestimated. When I trained clients, I always built in a recovery week (yes, one full week). This doesn't translate to an exercise-free week, but it does modify both intensity and duration of a workout. I always applied the 3:1 rule (three weeks of greater intensity/duration, one week lower intensity/duration). This "easy week" allows your body to recover, repair and get the most out of every workout.

4. Weight Loss Plateau
The weight peeled off when you first started working out, but suddenly you hit a wall. The weight stopped coming off. You're eating and exercising out the same. What's going on?

Weight loss plateaus can be frustrating, especially the closer you get to your goal weight. Losing unneeded pounds is more blessing than curse, and a real game-changer for the way we fuel our bodies. As we lose weight, our bodies require less energy (calories) to maintain daily operations. A 140-pound woman working out one hour a days needs fewer calories than a 190-pound woman working out an hour a day. Eating the same amount of food (albeit healthy) as you lose weight could be a culprit.

Another possibility for a weight loss plateau is adaptation. Your body simply needs a change, and shifting the intensity or style of a workout could do the trick. For instance, if you've been running five miles continuously most days of the week, change the pace of your workout to include intervals of a half-mile fast/half-mile slower. Another example is to incorporate some form of strength training if you're not already (FYI - yoga counts!). Check out any of my "No Excuse" workouts for ideas.

5. Chronic Injury
The pain in your [insert body part here] comes back almost as soon as you start [insert exercise here] again. This particular pain almost always disappears as soon as this exercise stops.

Maybe you're not burned out at all, but have a nagging injury. The "work-through-the-pain" method is dangerous! If you've got pain or a chronic injury, talk to your doctor or a physical therapist. Your injury could be serious, or as simple as strengthening a weak muscle. Regardless of the type of injury you may have, seeking professional help is the safest bet to recover and get back on track.