There have been numerous occasions where I have been standing at the start of a race over-hearing conversations between athletes boasting about the number of miles they have jammed into their training weeks. I am still yet, in many years of competing, to eaves drop athletes chatting about the effectiveness of their rest weeks. It seems like the common belief is that the more you do the better an athlete you are. An athlete that covers 100 miles is surely going to perform better than one that only fits in 60 miles. Makes sense, doesn’t it. The more hours you spend on your bike, on your feet, or in the gym the fitter, stronger, faster you will be become, right?
As endurance athletes we have a difficult balancing act between training load and recovery. Get this balance right and we can push ourselves to new levels, get it wrong and we risk developing Over Reaching and then Over Training Syndrome (OTS). A physical state where injuries and illness prevail and performances decline.
What is Over Training Syndrome?
Physical exercise is a stress on the body. A positive stress if the load is right and recovery is adequate. A negative stress if the intensity is too high and the recovery too short.
Too much training combined with inadequate rest pushes the body into a state of hyperactivity, activating the sympathetic nervous system and causing the release of stress hormones such as adrenaline and cortisol. This sympathetic form of overtraining causes a number of physical changes including an increase in heart rate, sleep issues and immune dysfunction, all of which are detrimental to optimal physical performance.
If the sympathetic stage of over training is ignored for a prolonged period the body becomes insensitive to the stress signals and full-blown OTS develops. At this stage of over-training the parasympathetic nervous system gets involved and your heart rate, rather than being raised, starts to lower. Symptoms can be very similar between these two stages, however, in the parasympathetic phase it will take the body far longer to recover. What was once a light training session, now becomes intolerably hard!
The Physical Signs of Over Training
So how can you tell if you are just experiencing the normal fatigue and stiffness from a hard training week, or if your body is struggling to recover and your normal adaptive processes are breaking down?
- Decrease in performance: This is the first and most important sign of OTS. If you find that you are struggling to maintain performances in training and/or races, then it is most likely time to give yourself a break.
- Persistent Fatigue: This is not just your average post workout tiredness but a persistent exhaustion with lingering muscle soreness, and an inability to get through training sessions.
- Decreased Immune Function: Excessive training in conjunction with inadequate rest causes an increase in the stress hormone cortisol. Cortisol impairs immune function leading to frequent colds, viruses & infections.
- Sleep Disturbances: Over-training’s activation of the sympathetic nervous system, and the subsequent rise in stress hormones, directly impacts the production of melatonin, the hormone that helps you sleep. If you start to find that you struggle to fall asleep, have disturbed sleep, or develop insomnia, this could well be your body crying out for some rest.
- Mood Swings: The nervous and hormonal changes caused through over-training can have a significant impact on your mental health, even leading to the development of depression and anxiety. Be mindful of starting to feel overwhelmed, moody or anxious.
- Physiological Changes: The increase in stress hormones causes other detrimental physical changes including increased resting heart rate (HR), increased sleeping HR, changes in HR variability, increased submaximal HR and even heart palpitations.
- Hormonal Changes: The rise in stress hormones disturbs the production of other important hormones leading to decreased testosterone levels, lower maximal and submaximal lactate and chronically high creatine kinase. All of these contribute to a decline in endurance performance. Female athletes should be aware that menstrual cycle disturbances are also common with the hormonal changes caused by OTS.
- Gastro-intestinal: Loss of appetite, weight loss, constipation or diarrhoea, loss of menstruation are all symptoms of OTS.
What to do:
As an endurance athlete it is important to be on the watch out for OTS. The simplest way to measure if you are over-doing things is to daily record your waking heart rate. This can be done through most GPS watches. Or the old fashioned wrist pulse count (to do this place two fingers on the radial artery at your wrist. Feel for your pulse and count the number of beats for 15s. Times this number by 4 and you have your HR).If your average waking heart rate increases by 5-10bpm (beats per minute) then there is a strong likelihood that your body is not recovering and that you are at risk of over training. This is not a fail-safe method, so do keep an eye out for any of the other physical signs of OTS mentioned above.
And always remember, sometimes the most effective training session is resting up and allowing your body to recover. Take pride in your rest weeks as they are key in allowing you to become the best athlete you can be!