Podcast, Science, Training

Non-functional overreaching with Cyril Schmit | EP#159

 December 10, 2018

By  Mikael Eriksson

​​Non-functional overreaching with Cyril Schmit | EP#159

Cyril Schmit, PhD, discusses non-functional overreaching for triathletes and endurance athletes. What is it, how can we identify it and prevent it and what are the biggest risk factors for it.

Discuss this episode!

  • Let's discuss this episode and the topic in general. Post any comments or questions in the comments at the bottom of the shownotes. Join the discussion here!

In this Episode you'll learn about:

  • What is non-functional overreaching, and how is it different from overtraining syndrome?
  • How can it be identified using subjective and objective markers?
  • How can it be prevented?
  • What are the roles of training volume and intensity in causing non-functional overreaching?
  • How important is the role of factors outside of training (life stress) in causing non-functional overreaching?
  • The relation between heart rate and non-functional overreaching. 

Sponsored by:


The Stac Zero is the world's quietest bike trainer. No noise and no tire wear, since it doesn't even touch the tire! It is also very portable and affordable. Use the discount code THATTRIATHLONSHOW for 20% off when you buy your Stac Zero indoor bike trainer.

The finest triathlon wetsuits, apparel, equipment, and eyewear on the planet. Trusted by Lucy Charles, Javier Gómez-Noya, Flora Duffy, Mario Mola, and others. Visit roka.com/tts for 20% off your order.


Related listening

Cyril Schmit's background

5:25  -

  • I began working in this research field 5 years ago at the National Institute of Sport in Paris, France. 
  • I found it an interesting topic to work on with triathletes because it combines both physical and psychological aspects. 
  • I try to diagnose overreaching syndrome to try and prevent it in triathletes. 

What is overreaching?

6:32 -

  • Overreaching is a step on the overall fatigue process.

    There are steps before overreaching where the athlete exhibits characteristics of acute fatigue.

    There are also steps after overreaching such as overtraining syndrome.

    At the end of the continuum is death. 
  • The functional part of overreaching can be interesting for coaches as it can be beneficial, but the non-functional part is risky. 
  • The core standard is performance of the athletes. 

    If you are in a non-functional overreaching state you will produce a reduced performance on a standardised test. 

    If you are performing well, you are likely in a state of functional overreaching and the fatigue level is not enough to impact performance, even if it's pronounced. 
  • We now know of several differences to help identify where the athlete is on the continuum.
  • For example in non-functional overreaching we begin to observe changing in heart rate recovery, heart rate variability and sleep quality, which are not found in a functional overreaching state.

    When you look at your heart rate at a standardised speed, e,g running at 12km/hour, you can observe a heart rate change that is geneally 5bpm. 

    For heart rate recovery it's more pronounced, so the average is around 10bpm difference in the first minute post exercise. The range goes from 6bpm to 18bpm difference. 
  • In a non-functional overreaching state, these differences pull the heart rate lower during exercise.

    In heart rate recovery, the amount of bpm you lose in the first minute after exercise is higher in a non-functional overreaching state. 
  • Non-functional overreaching is also associated with higher perceived exertion. 

Difference between non-functional overreaching and overtraining syndrome

13:39 -

  • Fatigue is a continuum, and as you go along the symptom there are similar symptoms overall.
  • However, three things make the distinction between overreaching and overtraining. 
  • First, the intensity of the symptoms is much higher in overtraining. 

    For example, the level of vigour are lowest when someone is in a state of overtraining.
  • Second, the consistency of the symptoms is higher in overtraining. 

    You present with more illness, more poor nights sleep, a lower libido etc. 
  • Thirdly, the duration of the symptoms is higher in overtraining.

    The deeper you go in the fatigue level the longer you need to recover. Overtraining can take years to fully recover from. 
  • I think we should consider that each function of the body involved in performance we can subject to overtraining at their own level. 
  • For example, at the muscular level when you increase the load the final step is injury. Similarly for temporal regulation, the final step is heatstroke. 

    Each time a main function of the performance reaches its own limit it endangers the athlete, and the performance. 
  • When we try to increase overall load in an athlete at a sufficient level to induce fatigue without overtraining, it's important to consider how each factor will adjust. 
  • Training is about periodisation of the performance related functions. 

    We have to take care not to overload each one of them. 

Achieving functional overreaching

16:44 - 

  • In studies we have found that 3 weeks of increasing training volume, without changing the proportion of training intensity, does not guarantee you will induce overreaching. 
  • However we have also found that 3 days of competition are sufficient to induce the first signs of overreaching. 
  • Basically there is no strict rule of the number of days needed to induce this state. 

    A few days are sufficient if you accumulate several factors associated with functional overreaching, such as higher volume at high intensity, plus lack of recovery, plus stress. 
  • It's often the case for amateur athletes that 10 days are enough to induce non-functional overreaching if you make no changes to your training.

    Half of these days would also be sufficient to dissipate the fatigue and its effect. 
  • However, this is only an average, and many factors will impact on how long it takes to achieve functional overreaching, or to move into non-functional overreaching.

    For example, in very well trained athletes, it may take a little longer. Conversely, lifestyle factors such as professional or family stress may make you reach non-functional overreaching sooner.  

Identifying non-functional overreaching 

22:44 - 

  • The first thing athletes may notice are changes to sensations both at rest (mood, memory etc) and during exercise (pain, perceived exertion). 
  • The second indicator is the reaction you have. 

    You will be more hungry, more inpatient, more aggressive. You may receive bad feedback from friends about your behaviour, which can help you diagnose this state. 
  • The final step is the physiology, where you see heart rate changes, heart rate recovery and heart rate variability.
  • The more of these you accumulate, the more you should consider your risk of overreaching. 
  • If we consider non-functional overreaching as reduced performance and increased fatigue, I believe that 100% of amateur athletes have already experienced this. 

    This is because outside of training they accumulate professional stressors. 
  • The reasons for overreaching in amateur athletes will be different for professional athletes, who normally only experience it as a result of increased training volume. 
  • For amateur athletes, the frequent activation of the central nervous system during the day outside of training leads to nervous fatigue. 

    This leads to falling deeper into the fatigue continuum. 

Neurological changes in non-functional overreaching

26:51 - 

  • 3 years ago, we did a study aiming to investigate what happens in the brains of athletes leading to functional overreaching after three weeks of overload. 
  • The fMRI data showed a reduced activation of the frontal area of the brain. 

    This is the part associated with complex mental operations. 
  • This was present only in non-functional overreaching athletes, not functional overreaching athletes. 
  • The results were precisely the same for people who were asked to do a 6 hour task in the fMRI and those who attended a normal work day.

    This means that you can have a source of stress that could be different (physical versus mental), but it causes the same effect at a nervous system level.
  • I think this is why amateur athletes will have experienced this state, because they are accumulating other stressors throughout the day. 
  • This doesn't mean all athletes need to decrease their training volume, but they have to take care of the external parameters which may be increasing their stress load. 

Practical tips for amateur athletes


  • Amateur athletes do still need to increase their training load, because you need to induce a certain level of fatigue to see improvements. 
  • However, you don't want to go deeper into the fatigue process, which can happen if you increase the training load to high, over too long a period of time. 
  • This can be accelerated by external factors which much be monitored and considered when assessing for non-functional overreaching. 

Impact of different types of training and disciplines on fatigue

32:51 - 

  • We know that both intensity and volume can lead to non-functional overreaching. 

    High intensity training as been associated more with non-functional overreaching, and low intensity may be beneficial for central nervous system recovery. 

    High intensity can induce changes in immune functioning, and it requires a high level of self regulation in order to push harder and tolerate pain. 
  • The higher the level of constraint on the organism, the greater the chance of overreaching.

    If you want to be 100% sure that you are overreached, first do running, then cycling, then swimming. 
  • From my research, we managed to consistently induce non-functional overreaching by increasing time spent at high intensity. 

Nervous system recovery

35:29 - 

  • The amount of recovery time you need depends on how much load you want to keep on the athlete. 
  • If you do 2 high intensity sessions on consecutive days, you have to be careful about how your muscles will respond. 

    You will likely see an improvement in performance, but on the muscular level it may lead to an intolerance and the athlete may become injured. 

    It's important to monitor how the athlete is managing using fatigue scales and RPE scales, as well as at the local level to ensure they are not developing an injury. 
  • To stimulate the athlete at the cardiovascular level without increasing muscle load you can conduct sessions in the heat chamber for example. 
  • In general, recovery recommendations are made on averages. The standard 2-day recovery guideline is because when you complete a hard session you induce a high level of constraint at the muscular level which progressively dissipates 36-48 hours after the session. 

    This does not mean it cannot be faster or slower in individual athletes. 
  • Athletes need to adapt their training to their personal response. If you are not recovered, you know not to complete the next hard session, or move it to later in the week. 
  • It's important for athletes to self-monitor their training load, and their stress load from other lifestyle factors, and make the necessary adjustments to their training plan. 
  • Many factors have been shown to change when you are in non-functional overreaching states (HRV, HR, RPE) but the consistency changes across individuals. 

    Due to this, subjective values are very important to monitor your fatigue. 

    Use subjective values as a complement to objective values. E.g. every time you use Heart rate, try to couple it with sleep quality and muscle soreness. 
  • Once you have selected the values you will monitor, try to do so at least 4 times a week to ensure consistency. 

    It's important to have repeated measures during the week to have a reliable point of view on how you're reacting to increasing training. 

    Once you do this, you can look at weekly patterns to see how you respond to various training factors. You can learn how you react according to a given stimulus. 
  • It's important to learn to work with each variable you include in your training parameters. 

Practical application

46:29 - 

  • Most training platforms include the opportunity to record a lot of these factors such as RPE, fatigue etc. 
  • Use these to improve your consistency with monitoring. 
  • There are also apps such as HRV4training which can be used to monitor heart rate variability and it syncs with other platforms. 
  • Even putting a notebook by your bed to jot down how you feel when you first wake up can be a good way to start looking at your sleep. 

Future developments in overreaching

47:33 - 

  • At the technologic level, research is trying to build tools to enable simple unbiased, low-cost, sensitive, reliable measures for coaches or athletes directly to use to measure this. 

    It's complicated because at the moment there are specific factors which are very effective (e.g. lactate measure) but we can't easily access this in everyday life. 

    Some are also very expensive, and some subjective measures may be unreliable. 
  • At the statistic level, research is accumulating data which is helpful because soon we should be able to say which kind of populations are more pre-disposed to overreaching and what factors may influence this. 

    This will help establish recommendations and guidelines for athletes, potentially giving them a percentage predisposition based on their training plans. 

    However, it will not be at the individual level for the athlete, so it's an in-between step for what we have now and what we hope to eventually achieve. 

Rapid Fire Questions

50:46 - 

  • What is your favourite book, blog or resource related to triathlon?
  • What is a personal habit that has helped you achieve success? 
    • Thinking across the field and applying to personal practice, and thinking we only know a little about the body. 
  • Who is somebody in endurance sports or your field of expertise that you look up to?
    • There is a German triathlete with long hair who raced at Kona last year, but I can't remember his name! 

Key takeaway

  • There are a combination of stressors from both in and outside training that can lead to non-functional overreaching.

    Make sure you are aware of the significant impact outside of training factors can be. 
  • We're not all the same in terms of how much training stress and volume we can handle, and your ability to manage training stress can change based on your life changes too. 

Mikael's personal experience

  • I was injured from December 2017 - April 2018. During this time I was only swimming and biking, and some months I couldn't actually cycle. 
  • In April I began to slowly get back into running, and only in May was I able to begin proper run training, and get back to my usual level of training. 
  • I improved a lot, but then I started to have problems on the swim in May, when I began ramping up the cycling and running. My muscles felt like spaghetti and I couldn't really get to any harder efforts. 
  • Towards the end of June and July I began having the same issues on the bike and run, and I was unable to get my heart rate up in the same way. 
  • I took 3-4 days completely off training, but then began training again as I had the Finnish Olympic distance Nationals at the end of August. 

    These were more than enough for me to recover, and I found I was able to get back to sweet spot intensity work. 
  • The last few weeks before the National Championships went well and I performed well in the race. 
  • I then took a week of a transition period, where I was training but it was lower than usually, and then had 3 weeks of hard training before Ironman Cascais 70.3, where I won my age group. 
  • I then had 7 weeks until the last Portuguese half distance race, which I was feeling excited for and felt in good shape. 
  • My training block started really well and I felt fitter than I had ever been before. However I then started to experience the same sort of issues with my muscles feeling empty and decreases in heart rate. 
  • It culminated in a brick workout where I had intervals in the bike, and I felt like I was bonking on the warm up! It was easy zone 3 intervals and I just about managed to hit them, but it wasn't a pretty workout! I attempted the run, and my legs just weren't responding at all. 

    I was running at high zone 1 and my heart rate was 10-12bmp lower than normal - it was 110bpm when I was doing 5min/km. 
  • I talked to my coach and we agreed I probably didn't recover enough from my first bout of non-functional overreaching. If I had recovered well then I probably wouldn't have had a reoccurrence as we'd changed my training following that - doing less training above my lactate threshold for example. 
  • At that point we ended my season and I took two weeks off. I'm now back training and feeling excellent. It's been an interesting learning experience! 
  • For me, changing careers a year ago and moving to Portugal, working long hours and training long hours is a lot to manage. This shows how important this is to consider. 
  • After the two weeks I took off I got back to training and I was performing really well - just to show that you don't need to be afraid of this time off if you need it. 

Links, resources and contact

Links and resources mentioned

    Connect with Cyril Schmit

    Connect with host Mikael Eriksson


    Hi! I'm your host Mikael,

    I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.

    I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show. 

    I sincerely want you to contact me to

    • Send me feedback
    • Give constructive critic​ism 
    • Request topics and guests for the podcast
    • Send me your triathlon-related questions 
    • Tell me that you've rated and reviewed That Triathlon Show so I can give you a shout-out on the show and tell you how much it means to me!
    Subscribe to That Triathlon Show and never miss an episode!


    Let's discuss this episode and the topic in general. Post any comments or questions in the comments below. I'll be here to reply and take an active part in the conversation, so don't be shy! 

    Mikael Eriksson

    I am a full-time triathlon coach, founder of Scientific Triathlon, and host of the top-rated podcast That Triathlon Show. I am from Finland but live in Lisbon, Portugal.

    Please contact me if you have feedback on the podcast or want to make suggestions for improvement or send in a question for a Q&A episode.

    If you are a long-time listener and appreciate the value the podcast brings, please consider taking a couple of minutes for leaving a rating and review on iTunes/Apple Podcasts, or wherever else you can think of leaving a rating and review.

    {"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

    Explore our products and services