It’s two weeks away from marathon race day. Legs should feel fresh, mind should be focused, and fitness should be at an all-time high. This is what you’ve trained for the past several months, never missing a workout. It’s time for all of the hard work, dedication to diet, and mental preparation to pay off.

But things feel off. Nailing goal workouts is difficult. Running similar times requires more effort. Fatigue is chronic despite adequate rest. Muscle soreness lingers.

Taking a week off from training doesn’t help and on race day, a personal record feels impossible. You start the race with little enthusiasm, each of the 26.2 miles spent thinking about the finish line. Rather than running a fast time, the goal becomes simply to finish. The excitement of the race is gone.

These symptoms represent a classic case of “overtraining syndrome” or OTS. OTS is something that many athletes may suffer from but may know little about.

What is Overtraining Syndrome?

Training dedication is important. But if you overtrain, you may not even make it to the start line.

Overtraining and Overtraining Syndrome Defined

Operationally, overtraining is defined as a training imbalance where stress > recovery.Kadam2016 When high levels of physical activity or high-intensity training are paired with inadequate rest and recovery time, performance suffers.

A separate but related condition to overtraining is known as relative energy deficiency syndrome in sport (RED-S). This syndrome results from an imbalance between dietary energy intake and expenditure. RED-S is characterized by loss of general health, proper growth, and reduced sport performance.Mountjoy2014 Many physiological functions such as metabolism, menstrual function, bone health, immunity protein synthesis, and cardiovascular health are negatively impacted by RED-S. This syndrome may be an early precursor to full-fledged overtraining syndrome.

Short-term overtraining is reversible with a proper rest period. In overtrained athletes, a rest period of one or two weeks can reverse many symptoms and lead to a performance rebound. This distinguishes overtraining from the more severe overtraining syndrome (OTS).

Overtraining syndrome results when overtraining continues for an extended period of time; some might call it burn out.

Since OTS is more severe than overtraining, recovery time is longer. It may take a rest period of weeks or even months to reverse OTS, maybe because it’s usually coupled with other types of stress: high altitude living, training monotony, suboptimal diet, and academic, occupational, or relationship strain.

Overtraining, or Under Recovery?

For athletes, the concept of overtraining might seem odd. You understand a high training load is needed to adapt and get better (known as “supercompensation”). However, too high of a training load with too little recovery is a poor way to achieve proper gains. Recovery is when the actual training adaptations occur, not during the training session. In fact, sometimes overtraining may not even be evidence of training too much, but recovering too little.

Your Brain and Body on Overtraining

It’s well documented that mental strain can have physical impact. When the mind wears down from overtraining (or stress outside training), it can impact performance negatively.

A woman sprinting, with an illustration of a bran behind her, showing what happens when you overtrain

Negative Mood States are Higher in OTS

The mental side of training and recovery are equally important as the physical. Overtraining can have wide-ranging effects on mental health and motivation, which can negatively impact day-to-day training and performance in competition.

One of the early signs of overtraining might be large emotional swings accompanied by more negative thoughts than normal. Mood changes likely occur due to alterations in endocrine hormones and changes in the nervous system.

Ultramarathoner and Athlete, Jeff Browning, has been there. He says there are a lot of puzzle pieces to running 100 miles and the mind is a big piece.

“I don’t let negative talk take root. I’ve learned to slay mental dragons by constantly switching to positive speak. That’ll give you an improvement in performance.”

Overtrained athletes exhibit higher levels of negative moods like tension, depression, anger, fatigue, and confusion. They also have lower levels of positive mood states such as vigor and motivation during training.Morgan1987 One study observed that in a group of athletes suffering from chronic fatigue, 80% had levels of clinically significant depression.

Overtraining may also cause feelings of edginess with symptoms of insomnia, lack of appetite, restlessness, and sleep disturbances. This may seem counterintuitive, since overtraining is usually associated with chronic fatigue, but it likely results from a “hyper-aroused” state. A constant, high release of stress hormones characterizes sympathetic overactivity; this is one reason an elevated resting heart rate is observed in overtrained athletes.

Neuroendocrine Dysfunction

The Hypothalamic-Pituitary-Adrenal Axis (HPA) regulates a majority of our body’s hormonal system. As part of the sympathetic nervous system (SNS), it helps respond and adapt to challenges by releasing stress hormones such as cortisol and adrenaline: think “fight or flight.”

Proper coordinated function of the hormonal and nervous system is critical for athletic performance, helping prepare the body for high-intensity exercise and competition by increasing heart rate and blood pressure and releasing catecholamines (hormones produced by the adrenal glands).

Overtraining syndrome causes central nervous system dysfunction; while release of stress hormones might remain high, their ability to cause the proper response in target organs is diminished. Hormones responding to exercise or low blood sugar are rendered ineffective.Cadegiani2017,Barron1985

This is the “autonomic imbalance” hypothesis of overtraining. Sympathetic/parasympathetic nervous system dysfunction and insensitivity to stress hormones results in impaired performance during racing and training.Lehmann1998 Overtrained athletes have a harder time performing. This suggests chronic fatigue can have effects in the brain as well as the body.

High-intensity, high-volume training may also result in reduced cognitive processing speed.Hynynen2008 For sports and race situations requiring decision making and composure, this is dangerous.

Heart Rate Variability as a Biomarker for Overtraining

A popular biomarker for athletes to indicate recovery status, heart rate variability (HRV) might be useful to detect potential overtraining. The applications of HRV are discussed at length in a recent podcast episode: "What You Can Learn From Heart Rate Variability" ft. Jason Moore.

HRV is a measure of the variability in the time between heartbeats (the beat to beat interval) and reflects autonomic nervous system balance–the balance of parasympathetic and sympathetic nervous system activity. Increased HRV generally indicates a good balance, whereas a reduced HRV may indicate a shift towards greater sympathetic activity due to chronic stress and overtraining.

Along with an elevated resting heart rate, lower HRV is found in athletes who are overtrained.Mourot2004 This could indicate nervous system imbalances as a result of overtraining/under recovery. Regardless, the underlying problem is too much stress.

Effects on Mental Health

A daily self assessment of mood and well-being might be able to point out a possibility of overtraining or a path toward OTS. Athletes know their bodies well, and a simple mood check-in might be a quick way to assess recovery status.

Feeling a bit off during a workout? Less motivated to train? Recognizing changes in mental state during training can indicate when to dial back the intensity or take extra recovery time.

How Overtraining Influences Performance

A heads-down training approach is something to be admired, and it’s a way many athletes train in hopes of better performance on race day. But it’s a thin line. Overtraining, and not allowing enough recovery time, can actually impair performance.

Training, Racing, and OTS

While no true biomarkers for overtraining exist, one sure sign of overtraining is “an inability to sustain intense exercise and/or a decrease in sport-specific performance.”Meeusen2013

In other’ll suck on race day.

In the short and long term, a state of overtraining in endurance athletes has been shown to decrease time to fatigue by 27%, reduce power output by 5.4%, and increase trial time by 9.8%Urhausen1998,Halson2002–it kills performance measures

Along with reducing performance and work output, overtraining increases the effort required to sustain the same level of intensity: running at the same speed feels harder, lifting a lighter weight seems more difficult.

Athletes report a higher rating of perceived exertion (RPE) for the same workload when they are overtrained versus well-rested.Kreher2016

While endurance athletes are often the subject of overtraining talk, it is important to realize that no athlete is immune. Overtraining syndrome has been observed in endurance athletes, strength athletes, and elite judo athletes.Lehmann1992,Fry1994,Callister1990

The Immune System Suffers in Overtrained Athletes

Of all the things athletes want to prevent, arriving at the starting line sick or losing training time due to illness are high on the list.

Overtraining severely impairs immune system function, leading to increased risk of illness and infection.MacKinnon2000 Being around group of teammates or training partners in gyms, sporting facilities, and public venues only increases this risk by exposing athletes to more pathogens and infectious bacteria.

Depressed immune function and higher rate of infection are consistent findings in studies of overtrained athletes. In particular, athletes training at high volumes seem especially prone to upper respiratory tract infection (URTI),AtiasVaron2017 a viral infection of the nose, throat, and airways.

The immune system is less able to fight pathogens during overtrainingMacKinnon2000 due to a lower number of immune cells fighting bacteria. Even the most elite athletes are at risk. Olympic athletes classified as chronically fatigued are shown to have higher levels of infections leading up to the games,Kingsbury1998 a period where they are undergoing strenuous training.

Recovery and nutrition strategies targeted at improving immune function may prevent illness during overtraining. Increasing dietary carbohydrate and intake of certain polyphenols (plant micronutrients) are effective in supporting sportNieman2017 performance and anti-viral capacity of athletes.

A female runner with her hands on her head, resting after a difficult training session

Preventing and Treating Overtraining Syndrome

Taking adequate recovery time to bounce back from overtraining presents a major setback, so preventing overtraining should be one of every athlete’s goals.

However, if you’re feeling overtrained or suffering symptoms of OTS, the first step is to immediately reduce training volume. This might involve low-intensity training or active recovery. In some cases, an extreme amount of rest may be necessary to prevent full-fledged overtraining syndrome from developing.

Below are some strategies to optimize recovery, prevent the onset of overtraining syndrome, and treat symptoms if you find yourself in an overtraining rut.

A male cyclists making a turn on the road, showing how to prevent overtraining.

A Well-Planned Training Program is the Key to Success

The best way to prevent overtraining is to stick to a well designed training program. Athletes in all sports tend to over-perform on the easy days and underperform on the hard days.Foster2001 Don’t make this mistake

Having a coach or a training partner to provide accountability and support throughout training can be helpful here. A support system can also keep you accountable if you need a few days off. Training partners can encourage the need to rest and remind you bigger things are down the road.

The Importance of Getting Enough Zs

The scientific literature is consistent: the body needs sleep. Inadequate sleep negatively affects areas of performance such as memory and attention, injury risk, speed, and endurance.Simson2017 Sleep is often sacrificed by athletes in favor of training or other lifestyle demands, such as travel, competition schedules and work.

Overtraining is associated with sleep disturbances.Hausswirth2014 Athletes should pay extra attention to sleep time and sleep quality, following some key strategies to enhance sleep hygiene and promote optimal recovery.

Increase sleep duration by getting seven to nine hours of quality sleep each night (recommended for all adults).

Athletes may need even more sleep due to higher training volumes, as it’s necessary to restore mental and physical functions.

Research indicates that sleep extension improves several measure of performance in athletes.Mah2011

Sleep can treat overtraining symptoms too, and is perhaps the best recovery tool available to athletes. Take a few rest days and focus on sleep if you find yourself experiencing training fatigue.

It can help to optimize sleep environment with a cool, dark room, free of electronics and artificial light–all are shown to increase sleep quality. Adding a nutritional supplement into to a sleep routine can further promote high-quality sleep. Ingredients like magnesium glycinate, L-glycine, and L-theanine promote sleep and enhance the recovery process in athletes who may need help getting some proper shut-eye.Nielsen2010

Fuel for Success

Optimal performance and recovery require proper fueling at every stage of training. Inadequate carbohydrate and protein intake, in addition to long term negative energy balance, impair recovery and lead to symptoms of overtraining. Even with proper planning, studies show that many athletes fail to meet a sufficient calorie intake to maintain energy balanceLowery2006 and might suffer from vitamin and nutrient deficiencies.

Protein is vital for tissue restoration, muscle building, immune function, and recovery from hard training sessions. Athletes in training need more protein to support training and recovery needs. Increased protein intake can also prevent unintended loss of weight in the form of lean muscle mass.

Up to 1.7g/kg of bodyweight in protein should be consumed for athletes in a variety of disciplines such as endurance and strength training to prevent muscle breakdown and support immune system function.

Adequate intake of carbohydrates to support training intensity and promote recovery is another important factor in preventing overtraining. While low-carbohydrate diets may have a place in some programs, sufficient intake of carbohydrate to support high-volume and high-intensity training in athletes is recommended.

Studies provide evidence that less adaptation to training occurs in glycogen-depleted endurance athletes, and that symptoms of overtraining can be prevented by a high carbohydrate intake during times of high training load. Athletes consuming a high carbohydrate diet containing 8.5 g/kg of carbohydrate during a period of high training maintained better performance and mood compared to a group consuming a lower carbohydrate diet containing 5.4 g/kg throughout the same training program.Achten2004

What if you are feeling overtrained, sluggish, or in a slump? Try to eat yourself out of overtraining by increasing your calorie intake, consuming high-quality protein sources, and eating foods rich in a variety of nutrients. Energy insufficiency is often a cause of overtraining, and giving your body what it needs can get you back to training.

Track Biomarkers

Staying in touch with yourself on a day-to-day basis will let you become aware when things seem off. Take a daily mood assessment before and after training. Is your attitude or willingness to train more negative than usual?

As discussed above, heart rate variability (HRV) tracking can also let you know if you’re overtraining. Getting your blood work done to test for possible endocrine or metabolic imbalances may be a more in-depth but worthwhile assessment of training status.

Could Ketone Esters Help Prevent Overtraining?

Recently, an increasing number of athletes are experimenting with the ketogenic diet and exogenous ketones as tools to enhance endurance sport performance and recovery. Strategic use might help athletes avoid overtraining, but there is still a lot of work to be done to understand their full potential.

Early studies suggest that ketone esters might accelerate muscle replenishment.

For example, athletes who added beta-hydroxybutyrate or BHB to a post-workout meal, set themselves up for enhanced muscle protein synthesis, indicated by increased signaling of the growth regulator mammalian target of rapamycin complex 1 (mTORC1).Vandoorne2017

Another possible application for ketone esters is to help the body store carbohydrate in the muscles as glycogen. Replenishment of muscle glycogen was accelerated following ketone ester supplementation when coupled with in IV infusion of glucose.Holdsworth2017 The jury is still out here, as another research group didn’t see the same effect on glycogen when the ketone ester was taken with a post-workout shake.Vandoorne2017 Because of the powerful effect of ketones on the body, it’s certainly likely that adding ketone drinks to regular nutrition could boost muscle recovery.

Overtraining is a Delicate Balance

Like rain clouds in the distance, overtraining threatens any athlete in a hard training block. Dedication and overuse is a thin, looming line that many athletes don’t realize they cross until it’s too late. For many athletes, it’s probably easier to push harder than pull back.

But perspective is necessary. If you’re worried about overtraining, speak to a coach or friend and hold yourself accountable to get necessary recovery time. Learn to listen to your body for whispers of overtraining. It’s a complex scenario involving mental health, nervous system function, and physical symptoms that decrease performance in the short and long term.

Importantly–don’t beat yourself up about it. A black hole of overtraining can be a dark and lonely place, so getting help is one of the best ways to treat OTS. Be patient, recover properly, know it’s a process and take the necessary steps to try and prevent overtraining before it’s too late.

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