When it comes to healthy habits, too much of a good thing can backfire, and that applies to exercise as well. While most people suffer from lack of exercise, once you get going, it can be addictive and some people do end up exercising too much — either by exercising too intensely, and/or too frequently.

However, a really important part of creating optimal fitness is recovery. An equation to keep in mind is that as intensity increases, frequency can be diminished.

For example, as a weak beginner, you can do high intensity exercise three times a week and not put much stress on your system. But once your strength and endurance improves, each exercise session is placing an increasingly greater amount of stress on your body (as long as you keep pushing yourself to the max).

At that point, it’s actually wise to reduce the frequency of your sessions to give your body enough time to recover in between. In fact, you need to allow your body to fully recuperate in between sessions in order for the exercise to remain productive.

Seven Signs You May Be Overdoing it

The featured article by personal trainer Jennipher Walters addresses signs of overtraining that are commonly overlooked or misdiagnosed. The following seven symptoms may signal that you need to cut back a bit and allow your body to recover between sessions:

1. Exercise leaves you exhausted instead of energized.
2. You get sick easily (or it takes forever to get over a cold)
3. You have the blues
4. You're unable to sleep or you can't seem to get enough sleep
5. You have ''heavy'' legs
6. You have a short fuse
7. You're regularly sore for days at a time

The Higher the Intensity, the Greater Your Need for Recovery

If you’re doing high intensity interval exercises, it's NOT recommended to do them more than three times a week. Both Phil Campbell and Dr. Doug McGuff have addressed this in previous interviews. If you don't allow your body to fully recuperate and rebuild, your efforts will not pay off beneficial dividends.... especially if you’re exercising to get healthy and live longer.

One of the keys here, as with any exercise program and lifestyle change, is to carefully listen to your body. I can provide you with guidelines and principles but ultimately the key to your success will be learning how to be sensitive to the feedback your body is providing you and then honoring that feedback.

With exercise you have to pay careful attention to recover if you tend to be someone who pushes yourself hard. If you only work out occasionally, this is a non-issue. But for those who are really committed and disciplined, it is very easy to over train, so please understand that recovery is every bit as important as training and if you work out too much you will not achieve the results you're seeking.

Over or Underestimating Yourself Could Nullify Your Efforts

As described in the featured article, many make the mistake of pushing themselves too hard. Others don’t push themselves hard enough. In order to maximize your workout efforts, it is important to strive for that 'Goldilocks' Zone' where you're pushing hard enough to challenge your body at your current level of fitness, while allowing your body to recuperate in between.

Needless to say, this ratio will change over time, and that's the point — many people forget they need to continuously up the ante as their fitness improves. Similarly, you need to look for signs of pushing yourself too hard when the addictive qualities of exercise start to kick in.

This is especially important as it applies to high intensity exercises. As mentioned earlier, doing high intensity interval training more than three times a week can backfire and become counterproductive. This is because when you work your fast-twitch fibers, it takes about 48 hours for that fiber to heal and fully recover. This is twice the recovery time needed for long and slow exercise, which only work your slow-twitch fiber. These can typically heal in just one day.

Earlier this year, I realized I was feeling unusually fatigued between sessions, as I was doing three Peak Fitness sessions per week. I ended up first reducing the intensity of my exercise by about five percent (instead of getting my heart rate to 173 or so, I would only bring it up to about 163).

Later, I switched to doing just two sessions per week instead of three. It’s important to not get too attached to any one particular program, but to continuously keep adapting your regimen as you go along. Most recently I reduced my Peak 8 session to a Peak 6 session, but I increased the intensity back up so now I get my heart rate from 170 to 174. But I only do them once a week unless I am unable to do my strength training, then I increase to twice a week. 

So have fun, play with it, and be very careful to listen to your body both post exercise and in the interval between exercising. If you are feeling great and have plenty of energy, that is likely a good sign you are not over exercising.  But you know your body better than most and if you know this is a risk for you, then implement the cautions I advise. However if you know you will never push yourself that hard then you need to ignore the caution principle until you have pushed yourself hard enough to know you have overtrained.

So, how do you know if you’re sufficiently recovered from your exercise? One tip gleaned from Dr. Doug McGuff is that you know you’re recovered when you have that restless energy and feel like you have to engage in some type of physical activity. You will just want to work out.

Strive for Balance

While high intensity interval exercises accomplish greater benefits in a fraction of the time compared to slow, endurance-type exercises like jogging, I do not recommend limiting yourself to Peak Exercises alone. Ideally, to truly optimize your health, you'll want to strive for a varied and well-rounded fitness program that incorporates other types of exercise as well. Without variety, your body will quickly adapt.

I recommend incorporating the following types of exercises to create a well-rounded fitness program suitable to your current level of fitness:

You need enough repetitions to exhaust your muscles. The weight should be heavy enough that this can be done in fewer than 12 repetitions, yet light enough to do a minimum of four repetitions. It is also important NOT to exercise the same muscle groups every day. They need at least two days of rest to recover, repair and rebuild. Exercise programs like Pilates and yoga are also great for strengthening your core muscles, as are specific exercises you can learn from a personal trainer.

• Interval (Anaerobic) Training: This is when you alternate short bursts of high-intensity exercise with gentle recovery periods. To perform it correctly, you'll want to raise your heart rate to your anaerobic threshold, and to do that, you have to give it your all for those 20 to 30 second intervals. (As a general guideline, you can calculate your anaerobic threshold by subtracting your age from 220.) For a demonstration, please see the following video.
• Strength Training: Rounding out your exercise program with a 1-set strength training routine will ensure that you're really optimizing the possible health benefits of a regular exercise program. You can also "up" the intensity by slowing it down. For more information about using super slow weight training as a form of high intensity interval exercise, please see my interview with Dr. Doug McGuff.
• Core Exercises: Your body has 29 core muscles located mostly in your back, abdomen and pelvis. This group of muscles provides the foundation for movement throughout your entire body, and strengthening them can help protect and support your back, make your spine and body less prone to injury and help you gain greater balance and stability.
• Stretching: My favorite type of stretching is active isolated stretches developed by Aaron Mattes. With Active Isolated Stretching or AIS, you hold each stretch for only two seconds, which works with your body's natural physiological makeup to improve circulation and increase the elasticity of muscle joints. This technique also allows your body to help repair itself and prepare for daily activity. You can also use devices like the Power Plate to help you stretch.

Less Really is More, When it Comes to High-Intensity Exercise

One of the major benefits of high intensity exercises is that it allows your body to produce human growth hormone (HGH), commonly referred to as “the fitness hormone.” However, as explained by Dr. McGuff  in a previous interview, once you're fit, you really don't need frequent spurts of growth hormone production.

At that point, recovery actually takes precedence as being more important, and your recovery period could be anywhere from three to seven days. In fact, he strongly recommends NOT exercising too frequently once you are in fit condition, and here's why:

"[Y]our adrenal gland… sits right above your kidneys, and it's arranged in layers. On the outermost layers, you have mineral corticoids that control your sodium and your electrolyte levels. In the middle layer, you have your corticosteroids that control sugar and generate stress hormones. And in the innermost layer is where you generate growth hormones and the sex steroids, or that's involved in the axis, in the feedback loop that generates that.

The old saying in medical school to memorize the three layers is "salt, sugar, sex" – the deeper you go, the better it gets. But you got to remember, your adrenal gland is an integrated organ. Those three layers are not perfectly divided. If through high-intensity exercise you're trying to hammer that adrenal gland three times per week, but now you're much stronger and your body hasn't fully recovered from your Monday session and you come back and hit it again on Wednesday… you're going to tap down into that deeper level.

Instead of growth hormones spurt, you're going to get in a cortisol spurt. You're going to completely undermine what it is that you're after."

http://fitness.mercola.com/sites/fitness/archive/2012/12/28/7-hidden-signs-of-overtraining.aspx?e_cid=20121228_DNL_art_1