Training overload: quick thinking can ensure proper recovery!

When pursuing improved performance through a dedicated training program, one of the biggest pitfalls that athletes make is thinking that ‘if some is good then more must be better’. However, it’s not just that this reasoning is flawed; a relentless build up of training intensity or volume without adequate rest and recuperation can result in plummeting performance thanks to phenomena known as overreaching and overtraining.

What is overtraining?

Each time you train, you break down muscle fibres and reduce your body’s stores of energy. This means that immediately after you train, your performance potential is actually lowered. The good news is that given adequate rest and enough of the right nutrients (fluid, electrolytes, carbohydrate, protein, vitamins and minerals) needed to replenish your body’s stores, you will not only recover from that training session, but your body will also undergo a process of ‘adaptation’.

Adaptation occurs as a result of a training stimulus, and is designed to help the body become stronger and withstand that stimulus better the next time next time around. There are a number of adaptive processes that occur as a result of running. These include:

·       The removal of debris and various metabolites associated with exercise (eg lactate).

·       Repair to muscle fibres, which sustain micro-tears, particularly during intense or unaccustomed bouts of exercise.

·       An increase in the production of relevant muscle enzymes – eg, those needed for energy production in various energy pathways, or involved in muscle protein synthesis.

·       Increased activity of genes involved in the synthesis of mitochondria (the cells’ energy factories).

·       Replenishment of stored muscle carbohydrate (glycogen).

However, without adequate rest and nutrition, recovery and adaptation may not occur. If there’s insufficient adaptation, you’ll fail to make progress. Insufficient recovery over the longer term on the other hand is more serious because it means the body is unable even to get back to where it was physiologically before the training session. If sustained over a number of sessions, you start to go backwards! Although periods of increased training/insufficient recovery are often referred to as ‘overtraining’, the situation is more nuanced; the severity duration of any increased workload periods can lead to very different outcomes ranging from merely functional overreaching through to non-functional overreaching, and in the worst case scenario, overtraining syndrome (see box 1 below).

Box 1: Overreaching and overtraining

When we talk about recovery, adaptation and the failure to recover, we need to distinguish between short periods of overload and breakdown (which can actually result in good adaptations once sufficient rest is taken) with a more chronic failure to recover, which can lead to serious performance decrements:
Functional overreaching - when an athlete undertakes more training intensity/volume than normal but the periods of overload are short, this is known as functional overreaching. In these circumstances sports performance will temporarily decrease in response to training, but with adequate recovery, positive physiological adaptation will occur, with a commensurate improvement in performance capacity^(1,2).
Non-functional overreaching - when the periods of intensive training are long, or where adequate recovery is not taken, non-functional overreaching may occur⁽³⁾. In this case, the accumulation of training and non-training stresses lead to negative effects on markers of physical and mental well being, and a decrement in performance. Depending on severity, performance capacity may take several weeks or even months to return to normal.
Overtraining syndrome – is even more severe than non-functional overreaching and occurs when all the warning signs are ignored for extended periods of time. The accumulation of training and non-training related stress results in a long-term decrease in performance, very often accompanied by physiological and psychological fatigue and/or illnesses⁽⁴⁾. This response to a prolonged training overload has a severe impact on an athlete’s health, and can require several months or even years for a full recovery. Overtraining syndrome is often characterised by increased levels of cortisol – the body’s main stress hormone⁽⁵⁾. In addition, decreased testosterone levels (a muscle building hormone) and lowered altered immune status are also present⁽⁶⁾. Indeed, overtraining syndrome is classified medically as a neuro-endocrine disorder, where the normal fine balance in the interaction between the autonomic nervous system and the hormonal system is disturbed, leading to a reduced ability of the body to overcome stress and heal itself⁽⁷⁾.

Overtraining signs

All athletes will functionally overreach at points during the year; indeed, attaining a degree of functional overreaching may actually be the goal in some training scenarios (eg an intense training camp for a week). And providing this is followed by a sufficiently long period of rest during which adaptation takes place, targeted functional overreaching can be a positive strategy for making performance gains.

The problem however is that the boundary from functional to non-functional reaching is easily transgressed. And from there, the pathway to overtraining syndrome is an easy one to be lured along. That’s because overtraining is an insidious and stealthy process that can creep up on you gradually, without you realising what’s wrong until it’s become serious enough for you to require a long layoff to recover. It follows that as well as designing your training program carefully (ie no sudden and sustained increase in volume/intensity and ensuring ample rest and recuperation), some kind of monitoring or early warning system of non-functional overreaching (or worse, overtraining syndrome) is crucial for any athlete who wants to ensure that they stay on the right side of the training vs. recovery equation.

While all athletes are different, there are a number commonly observed symptoms of overtraining, many physical but some psychological/behavioural. These include⁽⁸⁾:

Physical

•          Drop in performance

•          Fatigue and tiredness

•          Leaden or ‘heavy’ legs even after a day or two’s rest

•          Generalised aches and pains for no apparent reason

•          Frequent coughs, colds or other infections

•          Weight loss

•          Poor appetite

•          A raised resting heart rate when checked first thing in the morning

•          Restless or aching legs at night

•          Loss of sex drive

•          Inability to relax

•          Recurrent overuse injuries

Psychological/behavioural

•          Difficulty sleeping/poor sleeping patterns

•          Feelings of depression, irritation or anger

•          Boredom or lack of motivation

•          Difficulty concentrating

•          Increased sensitivity to emotional stress

Of course, just one or two of these symptoms doesn’t necessarily mean you’re overtraining. But if you start to feel tired, are experiencing an unexplained drop in performance and some of the other symptoms described above, the chances are that could be on the way to developing overtraining syndrome. And given that overtraining syndrome is known to cause perturbations of multiple body systems (neurological, endocrine system, immune system) coupled with mood changes, athletes are very likely to experience a wide array of these symptoms, not just two or three⁽⁹⁾.

Are you at risk?

What’s the best way for athletes to know if they’re on the road to overtraining syndrome? Unfortunately, there are no simple blood tests or levels of biomarkers that can measured to give a definitive or even reliable indication of when an athlete has progressed beyond functional overreaching⁽¹⁰⁾. And even if these parameters can be measured, many of them require access to expensive resources or laboratory equipment that are beyond most individuals, sporting clubs and organisations⁽¹¹⁾. Moreover, decrements in performance require physical performance testing to monitor poor adaptation and/or insufficient recovery; however regular testing along these lines is often undesirable because it only serves to further overload the athlete! The psychological symptoms described above are useful indicators (in conjunction with physical symptoms) of when athletes overstep the boundary, but of course, that’s too late when prevention rather than cure is the goal.