Podcast, Recovery, Training

Fatigue management with James Teagle and Lachlan Kerin | EP#204

 October 21, 2019

By  Mikael Eriksson

Fatigue management with James Teagle and Lachlan Kerin | EP#204

TTS204 - Fatigue management with James Teagle and Lachlan Kerin

Scientific Triathlon coaches James Teagle, Lachlan Kerin and Mikael Eriksson get together to discuss fatigue. How much fatigue is acceptable to experience in triathlon training, how can you manage fatigue, and how do you adjust training and other factors if you end up carrying too much fatigue?

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:

  • Acute versus accumulated fatigue and how they should be treated differently. 
  • Different kinds of fatigue: peripheral (muscular), central (nervous system), mental, and general. 
  • Managing fatigue through training: repeatable training weeks vs. two weeks hard, one week easy. 
  • Assessing fatigue with objective and subjective measures (perceived fatigue, motivation, RPE, performance, heart rate, HRV, etc.)
  • When and how should you adjust training (or lifestyle factors) for fatigue? How do you know when enough is enough?

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Q: How fatigued should you feel when training?

I've heard that a training week shouldn't be so hard you can't repeat it 4-5 weeks in a row, but they also say you need to push your body to get super compensations. How can you evaluate fatigue? What to do in the last hard week before an easy week?

3:50 -


  • With acute fatigue it's usually fairly clear where it's coming from. It may be a big session, or a particularly challenging one - e.g. very hot and causing dehydration. 
  • Acute fatigue is quite manageable, which is the difference between it and chronic fatigue which can take a long time to alleviate.

    Chronic fatigue builds up days, weeks and months.
  • These are not necessarily caused by training - acute fatigue could come from a poor night sleep, whereas chronic fatigue could be your day job becoming really stressful while maintaining the same level of training.
  • Accumulated fatigue could come from doing 11% in sessions over 5 days, or it can be from doing 101% in all sessions over 3 months. 


  • Acute fatigue can be alleviated with rest, but accumulated fatigue builds up over time. 

    It makes you feel lethargic, and can reduce your motivation to training or life in general. 

    It's important to manage fatigue before it gets to chronic fatigue. 

Different types of fatigue you can feel

9:26 - 


  • Fatigue is fatigue, wherever it's coming from - they need a slightly different approach but it'll have an impact on your performance no matter where it's coming from. 
  • You need to approach the types slightly differently, the list I have are:

    - Metabolic fatigue: caused by excessive training with inadequate recovery.

    - Central nervous system fatigue: lack of good motivation and power production.

    - Peripheral nervous system fatigue: more localised in your muscles, you may feel a lack of power from certain muscles.

    - Psychological fatigue: feeling nervous will increase your psychological fatigue, or it might be from outside training. 

    - Environmental fatigue: need to ensure you have something to motivate you - keeping everything the same can increase this type of fatigue. 
  • There will be times you can push through fatigue but it's important to identify where it's coming from 
  • E.g. with psychological fatigue, if it's coming from a competition you need to identify that, but if it's coming from outside of training you may need to address it. 
  • Metabolic and central nervous system fatigue need to be addressed as soon as possible, and shouldn't be left to get too far. 
  • Ideally you don't want to let any of these fatigues get too far. 


  • There is interplay between all types of fatigue. 
  • From a coaching perspective, any fatigue needs to be identified, and over time we can then decide if it becomes concerning. 
  • If we can look back and see if there's a reason for the fatigue that we expect it may be less concerning. 

    But if it's been building up over time, and we assess this through objective and subjective data, it becomes concerning. 
  • It is certainly concerning if it's in your day to day life and is affecting things outside of training. 

How to manage and get rid of fatigue

15:34 - 


  • The two areas that are most easily addressed are nutrition and hydration.

    If we look back and you'e lacking energy availability in sessions, that is easily addressable in the short term. 

    Getting the fluid balance right in your body can really help, and may support you getting out of fatigue without needed to address your training load.
  • Sleep is another factor that is slow important. 

    For some people it can be an easy factor to address, but not always - e.g. small children waking you up in the night. 

    In situations where you can't address it easier you may need to address the training, by not doing sessions in the morning or putting hard sessions later in the day. 

    You may even need to back off the volume and keep the quality there. 
  • Sleep hygiene is also easily addressed - getting off electronic devices 30 minutes before bed can help. 
  • Doing things such as meditation or mindfulness can make a big difference to your mental health and stress levels, which can improve fatigue as well. 
  • If fatigue is affecting your bio-mechanics, particularly in running and swimming, it really needs to be addressed. 


  • Remember why you're doing the training - you're not training to be tired, and you don't need to be tired from training. 
  • You're training to be a better athlete, and this involves rest, nutrition, stretching and mobility, getting your head in a good place etc. 
  • Yes you can accept fatigue, but don't keep pushing against it when it increases. 

    If you have a coach you can discuss it with them, but generally you need to be smart about the training you're doing. 

    If you need to miss a couple of sessions to get yourself out the hole, that's the right thing to do. 

Repeatable training weeks or a ratio schedule?

21:01 -


  • Whatever you do, it needs to be consistency because this is what drives performance improvements and adaptations.
  • I personally prefer 4-5 week repeatability with making sure you've got enough rest in there. 

    The first thing you plan in is the rest!
  • With this approach you want to make sure the weeks aren't impossible. 

    You should have a bit of tiredness but you can tick off each week and know it's doable. 
  • At the end of 4-5 weeks you might consider having a rest week before the next block. 
  • In terms of 2 week on/1 week off - I've seen a lot of athletes do this, and I do think it works really well if you're someone who pushes themselves hard but has a lot of other life stuff going on. 

    It might help to have two weeks going fairly hard, then a week off where you have some down time and pull back the hours (20 hours down to 12 hours). 

    You need to do this consistently too.
  • You need to choose what works better for you and what fits more easily into your life. 
  • For me, I'd rather go 4-5 week because it allows consistency, but for some athletes it's just not possible. 

    If you can get more consistency in the 2 weeks on, 1 week off, then go for this. 

    It also allows more of a mental break which can be beneficial. 
  • For age groups training 10 hours a week, it again depends a lot on what else they're doing in their life. 

    You need to consider their job and working hours, and the other aspects of their life.


  •  I personally get more worried with the 2 weeks on, 1 week off if they use the 1 week to catch up on life. 

    Filling that 'week off' with lots of things outside of training that can also cause fatigue does eventually catch up in time. 

    Eventually the one week off isn't usually such an easy week anymore. 
  • I think the 2-3 weeks hard, 1 week easier, works for the elite athlete who has more time and doesn't do much outside of sport. 

    In terms of the majority of people, and self-coached athletes, I think the repeatability is better. 
  • For self-coached athletes, pick some key sessions that you want to do during the week and then depending on what happens during the week with work etc you can adjust to reflect that. 
  • Consistency over time for the majority of the year is the most important thing. 
  • You should never be afraid to take a week when everything in under 75% - you won't lose any fitness! 

    If life happens and you require an easier you, don't be afraid to put it in. 
  • You need to be clear about what the minimum effective dose of training is, and for many this is less than you might expect. 


  • I find I often change the pattern based on where they are in the season. 
  • Right now, I have athletes coming back from their time off so we'd aim for something that is repeatable week in week out. 

    As we get closed to race specific preparation we may go for harder weeks, and so it may change to 2 weeks hard, 1 week easier. 
  • It also depends how prone the athlete is to fatigue. 

    E.g. if the athlete is prone to fatigue but is a very good athlete, the 2 weeks on, 1 week rest may help them manage this fatigue. 

Assessing fatigue & thresholds for fatigue

32:54 -


  • I use heart rate and heart rate variance (HRV). 

    If your heart rate is getting very low it's a sign of fatigue. 

    HRV is a good assessment but it needs to be measured consistently during training. 
  • The most effective way of monitoring fatigue is by asking the athlete! 

    Working out through communication if it's fatigue and if it looks like unsustainable fatigue. 

    As a coach you build a relationship with an athlete and learn what their normal looks like, and whether they are too fatigued. 
  • Things like sleep disruption, not eating well, low motivation etc adds up, but the best way to catch fatigue early is to have an honest and frank conversation. 
  • You're generally trying to avoid excessive fatigue, but there should be an element of fatigue in their programme. 

    You need to identify if it's just fatigue from a certain session that you'd expected, or is it accumulated fatigue that's getting too much, which you can gather from the conversation. 
  • You could have a really good training plan, but maybe something happens in the family life or a big project kicks off at work. 

    As a coach you can't see this on TrainingPeaks, you just see the fatigue, so you need to be communicating with the athlete so you can make decisions taking into account all the variables. 

    You can quickly identify whether it's unusual, and if it is you may need to adapt what you have planned. 


  • I've had a few examples this year where the athletes family have been sick and their heart rate is going up over a few days, until they finally end up on the verge of sickness. 
  • I personally use HRV4Training, which I think is a very good programme.

    I don't necessarily use it day to day for my athletes, as it can easily be depressed for one day, but if I'm seeing a trend over time where the HRV is down I would look into it. 
  • I've had a few athletes working with Whoop Strap lately. 

    We've found that the first month or do is a teething period while it gets used to your body. 
  • If an athlete is reporting lack of sleep, particularly when coupled with high RPE in training you can guess fatigue is coming from there. 
  • A good litmus test for athletes is swimming without equipment. 

    When you're genuinely very fatigued, your swim form is usually the first thing that suffers. 

    If athletes are reporting that they're struggling in the pool to maintain form, particularly in long intervals, it's usually a good sign that you need to back off on the other disciplines. 
  • Looking at the bike and heart rate to power or pace, sub-threshold intervals should have this measure come down over time. 

    But high end VO2max intervals, if we see the heart rate being lower or suppressed it may be a sign of fatigue.

    It shouldn't always be a sign of gaining fitness, it can be suppressed because you're too tired. 


  • The most important objective measure is performance. 

    I tend to use a '3 day rule' - if something happens for 3 consecutive days or quality workouts (e.g. reduced performance) it's a call to look into things and ask the athlete how they're feeling. 
  • It should be combined with perceived fatigue and perceived effort the athlete is reporting in those sessions. 

    If they are finding they are more fatigued, or it's taking more to make the effort, it could be a sign of accumulated fatigue. 
  • It doesn't mean you need to change things right away, but if you start to accumulate too much fatigue then you may need to make changes. 
  • I use HRV4Training and find it brilliant, but it shouldn't be used in isolation - it needs to be combined with performance data, self-reported sleep quality and quantity and other self-rated metrics. 
  • Often looking at the baseline trend changes in HRV, this can be really useful for identifying fatigue. 

    You just need to ensure you remain in touch with how you feel, and don't rely totally on this metric - but it can provide a good guide. 

When to make changes due to fatigue

46:35 -


  • I never want an athlete to get to a point where they don't enjoy the sport anymore. 

    We are doing this for enjoyment!

    If I see an athlete getting towards that, I'll be quite worried. 
  • If it's a motivation and mental fatigue, it doesn't always mean you need to put in an easy week, you might need a week with more variability (e.g. terrain or session type). 

    Giving the athlete the chance to go out and do what they want for a week and be unstructured could also be the solution. 
  • Objectively, if I see more than 3-4 days of elevated morning heart rate, I will have a conversation with the athlete. 
  • Just looking at TrainingPeaks doesn't mean much, you need to chat to the athlete to gain context for the data. 
  • In terms of performance, we don't want to get to a point with fatigue where athletes are unable to push the intensity they have been previously, unless there has been a break that could explain it. 

    This is probably when we need to take a step back, understand what's happening and have an intervention. 
  • If we get to the point where they can't complete the same number of reps, it's definitely a worry. 

    If they did 280 watts this week, whereas they did 300 watts last week, but they got the same amount done it's probably not really a concern. 

    Threshold is a moving target, it's not the same from day to day so a little variability is acceptable. 
  • The addition of ERG mode to the masses means athletes are often chasing one number without changing it and listening to the body so much, which isn't always a good thing. 

    This is one of the biggest reasons athletes get accumulated fatigue in the first place. 

    This is a result of technology development, it's often not the athlete's fault. 
  • With heart rate, if it's more than 5-10 over for 20 minute intervals you'd be a bit worried that there's something going on. 

    Similarly if you see athletes doing VO2 efforts and they're not getting above 70.3 heart rate, it's probably a good sign to back off. 


  • You can't just identify one factor that indicates fatigue. 
  • You need to look across multiple sessions before you can identify this, and you need the qualitative data from the athlete too. 
  • Athletes are very emotional and can be quite reactive after training sessions. 

    It's important to look at the bigger picture, and make the decisions to pull back on training intensity. 
  • It's important to try and not react to one bad sessions, but be able to leave a session in the past and view the big picture. 


  • For me if there's 3 consecutive days where something seems to be out of the norm - e.g. perceived effort is high, performance is low etc. 
  • This is when we need to have a discussion, try to identify the root cause and then make adjustments if and as they are needed. 
  • There's no formula or equation, but you need to make some sort of root cause analysis and dig a little deeper. 

How far to push in race prep 

57:22 - 


  • For me it's down to the athlete. 

    If you have a good history of pushing yourself hard and recovering well, then push yourself to the limit where you feel quite fatigued before your taper. 

    However if you have an athlete who may be older or doesn't recover as well, then make sure you don't push yourself too hard. 
  • Consistency is what makes you a good athlete, so consistently training and following a structure that brings on your ability level is what is important. 
  • You shouldn't get to the end of your training phase and think you need to smash it because you're not where you need to be, you need to consistently build this up over time. 
  • If it's an 'A' race it's probably okay to take more rest. 

    Being fresh into races has a massive impact, and it's remarkable how fresh you can get without losing any fitness. 

    It's important to not be afraid to pull back from training going into races. 


  • If you're getting to the last Sunday before a taper, and you're praying for a taper to improve you, it's like hoping for a miracle. 

    You probably overdid it a bit and haven't had enough time to recover. 
  • Learning to take a day off is really important - professionals do this a lot. 

Take home advice

1:02:07 - 


  • Don't be afraid to take some time to adapt to the training. 

    Adapting is another part of training, and if we're not getting adaptations it's quite useless! 
  • Trust in yourself to back off, which is something a lot of athletes struggle with. 


  • As an athlete you've got to be prepared to take the recovery to ensure you're getting the best out of your training. 
  • You want to make sure that you don't repeat mistakes - there will be times you do push too far, but identify the factors that cause that and what it feels like to make sure you don't repeat it again. 
  • Learn what allows you to be consistent in training and apply that on a weekly basis.


  • Your body has no idea what you had planned, it only knows what you're actually doing. 

    Don't be afraid to adjust based on how you feel, but also on the objective and subjective markers. 

Links, resources and contact

Links and resources mentioned

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.

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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.

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