Why Overtraining Can Be Dangerous

by Terry Kozmor

As a personal trainer in the fitness world for more than 15 years, I have seen it all: people who have great success at getting (and staying) fit, people who fall off the fitness wagon, and people who spend too much time at the gym. The last group has always given me pause because spending too much time at the gym can be worrisome for many reasons. Let’s talk about the physical impact of overtraining.

One of the main benefits of working with a personal trainer is that he/she should be able to prescribe a workout regimen that includes an appropriate amount of time off. Not only will your trainer help you determine which days to work out, but they will also suggest the amount of time each workout should last. This ensures that you are getting enough cardio, enough strength, enough movement, and enough rest.

Why is rest important?

For starters—and very simply put—overtraining often leads to injury. Just because a professional athlete can work out for hours each day, that doesn’t mean that you should. The average person simply doesn’t have the capacity to expend this much energy and properly refuel the body on a daily, weekly, or monthly basis. When our muscles aren’t given enough recovery time, we overcompensate in another area and this is when injury occurs. Remember that oftentimes slow and steady wins the race when it comes to an exercise plan. Be sure to not only have adequate rest time between workouts (I recommend 24 hours), but also be sure to plan one or two rest days per week when building your workout routine. Use that time to stretch (foam roll or do yoga), treat the body (sports massage or salt bath), or simply rest.

Overtraining and the Gut

According to a recent study published in Science Daily, researchers discovered that overtraining increases the risk of gut damage. A healthy gut is critical for a healthy body and an overall healthy life. With compromised gut health comes risk of a weaker immune system, which ultimately leads to getting sick. It is critical to keep the gut as healthy as possible, especially when we are working so hard to maintain a strict workout regimen.

Overtraining and Performance Goals

A second concern of overtraining—one that I often discuss with my more competitive or athletic clients—is that training too much hinders performance goals. For example, if you are training for a marathon that is six months away, I would put you on a specific training plan that incorporates strength/resistance training, mobility, and running. If you skip rest days and are running or strength training an extra two days per week and get injured (see above), the goal of running a marathon in the next six months may no longer be realistic. Injury is just one common factor that leads to unmet performance goals. Exhaustion, fatigue, and plateauing are others that we see far too often. Stick to your plan. Incorporate rest days and make sure that you are taking care of your body in every way.

Signs that you are overtraining include:

  • Overly sore muscles
  • Poor sleep
  • Foggy brain/cognitive problems
  • Irritability
  • Abnormal heart rate

Any of these symptoms can be a sign that you are training too hard. Be sure to listen to your body and recognize when these come into play.

Preparing and Replenishing Your Body

Now that we’ve discussed the downsides to overtraining, let’s talk about how to properly prepare and replenish the body so that we don’t fall into the overtraining trap.

Time of Day

There are mixed reviews about when is the “best” time of day to exercise; however, I do not believe this is a one-size-fits-all answer. I tell my clients to work out when it best fits their schedule and their lifestyle. If you have the most energy in the morning and like to work out on an empty stomach, perhaps pre-work gym sessions are your best bet. On the flip side, if you need to feel properly fueled throughout the day and feel the most energized in the late afternoon, it sounds like after work is your best bet. Do whatever feels right for you.


I typically recommend that clients eat one or two hours before their workout and include fast-burning carbs like fruit so that their stomachs aren’t full but they have enough food in them to provide energy. Drinking coffee is another good way to give your body a boost of energy if you are particularly tired. Most importantly, make sure that you are properly hydrated!

During Your Workout

While water is the best thing you can drink during your workout (gotta stay hydrated!), many people need a little more flavor or “oomph,” especially when weight lifting. BCAAs (branched-chain amino acids) are a great addition to help increase muscle growth and decrease muscle soreness. These come in powder form so they’re easy to mix into your water.


It is critical to refuel our bodies to optimize performance and achieve the best possible results. When replenishing what was lost, it’s best to eat a meal that consists of low carbohydrates and protein (using a 3:1 ratio) within about 60–90 minutes of working out. Examples include a protein shake or chocolate milk.

Balance is Best

Being healthy is an all-encompassing lifestyle adjustment. We need to get at least eight hours of sleep, drink plenty of water, eat a well-balanced diet, maintain a healthy gut microbiome, and get enough—but not too much—exercise. Please remember that working out too much can be just as damaging as not working out enough.

Ixcela offers a personalized fitness plan with varied exercises to help you avoid overtraining and experiencing the symptoms explained in this article. Varied exercise paired with proper sleep and nutrition are the keys to gut health and reaching your full potential.

About the Author

Photo: Terry Kozmor

Terry Kozmor has been in the health and wellness industry for more than 15 years. After graduating from Northeastern University with a degree in exercise science, he began his career in fitness. In addition to being Ixcela’s fitness expert, Terry is also the Director of Fitness at Lynx Fitness Club in Boston, Mass., where he oversees a group of specialized personal trainers, group fitness instructors, and nutritionists. He is an avid athlete himself and you can often find him outside snowboarding, surfing, or hiking.

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Interested in learning more about Ixcela? Check out Ixcela’s microbiome test, personalized nutrition and fitness plans, and other tools to help you optimize your health.


Wiley. "Excessive exercise may damage the gut." Science Daily. 7 June 2017. www.sciencedaily.com/releases/2017/06/170607085452.htm.