The Dark Side of Over Exercising

Let me start by saying that exercise and movement are absolutely essential for a healthy lifestyle – we are not meant to sit at our desks and sofas all day. However, although I regularly advise clients on taking up exercise they enjoy, I’m finding that I’m actually having to tell some clients to exercise less or switch up the type of exercise they do. Why? Isn’t training every day the best thing you can do? Well, the answer is that it depends and there are dark sides to over exercising.

Just to clarify here, I’m using the term overtraining in a sense of an imbalance between training versus recovery time, which can be different for different people.

Here are some of the things to consider when you might be training too much and resting too little:

Overtraining and Adrenal Insufficiency

The adrenal glands are small glands located on top of each kidney, which produce hormones that you can’t live without, including sex hormones and cortisol. Cortisol helps you respond to stress and has many other important functions.

Research (1) has found that as part of overtraining people can develop something called Overtraining Syndrome (OS), which is linked adrenal insufficiency. This is because there is a direct link between stress and the adrenal glands, and the physical stress of overtraining may cause the hormones produced in these glands to become depleted. What may happen then? Conditions such as adrenal fatigue, characterised by persistent fatigue, even upon waking, sleep disturbances and digestive problems might develop. These of course would affect overall performance and you might be getting into a paradoxical stage where you are training more but your performance levels are going down.

Over Exercise and Leaky Gut

Relatively recent research has suggested that intense exercise can cause problems with our digestive tract and even cause something called “Exercise-induced Gastrointestinal Syndrome.” Simply put, strenuous exercise can damage the gut and let the bacteria that reside there potentially pass into the bloodstream. This is often called ‘intestinal permeability’ or ‘leaky gut’.

This ‘leakage’ of indigested particles and toxins from our gut in term might overstimulate our immune system. Leaky gut has been found to be linked to more serious autoimmune conditions such as MS and Rheumatoid Arthritis.

Cortisol and Weight Loss in Exercising

High intensity exercises help us release cortisol, which is a stress hormone. Normally this is short lived, and levels go down with rest. However, if we are overtraining in especially high intensity work out regimes, you are likely to be producing excessive Cortisol.

Cortisol is the primary stress hormone, which increases sugars (glucose) in the bloodstream, enhances your brain’s use of glucose and increases the availability of substances that repair tissues.

So, what is happening if you are over exercising to lose weight? You might be having a counterproductive strategy because your body is pumping Cortisol, which releases sugar into the bloodstream (even when you are not consuming refined sugars and carbohydrates!!!).

Also, don’t forget that Cortisol is also a catabolic hormone, which means that it actually breaks down muscle as opposed to other anabolic hormones!

Too Much Focus on Macronutrient Balance and not Enough on Micronutrients

If you are a regular ‘gym bunny’, you are likely to get into the whole culture of making sure you eat a high protein and low carb diet. You would buy kilos of chicken, tens of eggs, white or brown rice and maybe a bit of spinach or broccoli and prep once a week. Maybe you are having one ‘cheat day’ a week where you allow yourself to consume carbs and these are often bread, cakes, chocolate and takeaways. Maybe if you are running out of time you would grab a protein shake a protein bar or sugar laden electrolyte drink in lieu of a snack or a meal.

There is nothing wrong with food prepping per se ( I actually really encourage it for some of my busy clients) and watching your macronutrient intake ( these are your carbs, fats and protein), but my issue is that this way of viewing food completely disregards micronutrients – all the vitamins and minerals you need to stay healthy and support your exercise regime!

For example, exercise and particularly in the cases of over exercise, you are producing a lot of free radicals, which are molecules with a missing electron which move around and cause damages to organs and even DNA. And guess what? You need to counteract these to keep healthy – a lot of antioxidants are found in fruits and vegetables, the very foods some gym goers are excluding because of their higher carbohydrate content.

Vitamin C, which is high in foods such as peppers and oranges, for example, is not only a great antioxidant, but is also essential for the production of collagen, which you need for healthy supple joints when training.

Another example – Magnesium participates in over 300 bodily functions and also helps your energy levels and muscle contraction. Where can you find it? In green leafy vegetables and seeds and nuts.

So, the takeaway message is don’t just look at your macronutrient ratio, consider wider nutritional factors that help you keep healthy and recover after exercise.


1. Kreher J. Diagnosis and prevention of overtraining syndrome: an opinion on education strategies. Open Access J Sport Med. 2016;