Am I overtraining or is it likely another cause e.g. Long Covid?

I am currently suffering with severe exhaustion but not really any other significant symptoms hence I am querying overtraining as post viral fatigue seems unlikely. I am not aware of having had Covid but cannot exclude asymptomatic infection & Long Covid is now thought to be increasingly common. I do not really follow any training plan besides consistency & variety or aim for any periodisation. I do favour endurance/aerobic rather than intensity due to muscle strain susceptibility & a lifelong chronic back issue.

My resting HR has recently plummeted (due to Premature Ventricular Contractions often at 1:1 ratio see ECG). This has happened last in June 2021 where in fairness I was training a bit harder. I have recently stuck to mainly aerobic exercise yet it has has recurred. My sleep is never particularly great & Garmin Sleep & overnight Body Battery Recharge stats are likely unreliable due to PVC issue. HRV is recorded using the HRV4 app & so should be more reliable as I try to exclude PVCs from those recordings.

I can see no particular correlation between loads or intensity and rarely do any exercise in Z5 or above. But am I in subconscious denial? I would be appreciative if anybody with experience of what overtraining would look like can take a look & suggest the best path forwards as I am at a loss. I am reluctant to take total rest unless I can see a clear necessity as generally weeks off (albeit single ones only) in the past have done little for my subsequent energy levels. Although dropping my training load for an extended period did work last year with cardiac issue it has taken forever to regain any sort of fitness.

I did have cardiac scans etc a couple of years ago and was told that there was no problem & the PVC issue does resolve during exercise. It occurs mainly at lower RHR levels & I never get palpitations. As I have had the PVCs for many years I am viewing them as more a symptom of my current fatigue more than a cause. But I could be wrong as my recovery time could be compromised by the decreased cardiac output & hence my “Body Battery” is lower?

Hopefully other people might also learn from any advice or discussion that this post might generate. Many thanks in advance.


I forgot to say thanks to David at Intervals for creating such a useful tool for thorough analysis of such a wide variety of metrics.


Lots of good info and tracking. I have a few thoughts but my primary questions are:
• Do you get regular blood tests?
• Are they comprehensive?
• When was the last test?
• Do you have a good doctor or at least someone to look at them objectively (rather than from within allopathic sick-care)?

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Excluding all your non-activity problems, it doesn’t look like you’ve had much recovery/de-training in your training in the area highlighted. Your weekly training volume might seem doable, but I certainly would recommend reducing your training load every 3-4 or at worst case 5 weeks. Consistency includes rest.


Here are two graphs showing what the recovery weeks looks like in a progressive training load. Week 4 being the detrained week.


Can you upload the graph in much higher res?
It is hard to see exactly but couple of simple thoughts:
-without even simple training plan and some simple periodisation it is very easy to get overtrained when you ride a lot. Constant load for 8 weeks is much more risky than even much higher load but with rising persiodisation and rest weeks. /Training is a signal for your body to build muscles and adapt but adaptations take place during rest period, without it you just cumulate fatigue and go backwards, at some point your body will show you this way or the other (ilness, injury etc ) that it needs time to rest.
-you can compare 360tss load rode as 10-30-50-70-90-110 progression and same load but rode as 6x60tss .First will give you fitness and (with proper rest) build stamina, second one will give you chronic fatigue. If you ride 60tss after the first it will be a rest ride (just a half of what you body is prepared for). 60tss ride after 6x60tss is just another day of cumulated fatigue. From graph/fitness perspective both will rise the graph (it is just a rolling average) I’m trying to explain why your type of riding is making hard to build fitness as you said. On top of that 60tss rode as endurance is not the same as tempo or treshold. From your graph it looks like you are trying rise your fitness graph as fast as possible with strong hard efforts. Without proper amount of base/endurance it is taxing for your body.
-2/5 of the graph on the left side is very load heavy (much more tempo and treshold work over endurance rides, like 3 to 1?). Such amount of tempo work is risky without periodisadion.
-after that hard season on the left no proper rest, still tempo and vo2max rides (i know volume is much lower)
-if you feel tired you should rest, graphs can’t predict overtraining and your graph are kind of useless while you are not training and just riding. They can make more harm skmetimes.
-if the fatigue graph is not corresponding with your real perception, maybe your hr/power zones are set incorectly.
-most of the cyclists have to learn it hard way, but listening to your body is very important.
-if i was you i would take one week of proper rest physicaly and metaly (go to cinema, meet friends) and in your free time i would watch at least some basic training stuf like (wko5 annual training process for example). I mean if you are afraid that you will lose fitness, those podcasts and training basics will make you regain much higher fitness then you had in no time and with much lower risk of injury or overtaining
-ofc i would continue to investigate medical problems where needed.


Many thanks for your reply.

I do not get regular blood tests, my last was 2 years ago as a part of my Age 50 Wellness check that led to the Cardiac Investigations. I am a retired nurse & so agree that they could be important & illuminating. My hesitancy is that I want to explore other causes before costing the NHS even more money having being cleared from a very comprehensive blood & cardiac test perspective relatively recently & when I was probably exercising at a similar intensity. Also I suspect that if the GP took a look at my Intervals account they would quite understandably simply tell me to take a few weeks off. The cardiac tests were reviewed by a Consultant who I worked with & more importantly does regular marathons himself so his all clear would likely be more meaningful than an unfamiliar GPs. I do realise that health metrics can change in 2 years though so I will likely seek blood tests in a few weeks if my fatigue has not improved at all.

Interesting comment for two reasons:

  1. Agreed. Allopathic medicine doesn’t want people pushing themselves.
  2. I wonder if there’s some self-knowledge about the state of your training, i.e. having trained very consistently (good) without at least a small time of rest (not nec. good). (As has been mentioned above.)

Blood tests are important every year, more often for athletes or when any issues are indicated. I hear you about not wanting to add cost to NHS, but the cost is much greater for sick-care than it is for health-care. Better to see trends over time and catch issues early than letting them grow and requiring much larger investments to correct.

Thanks for your detailed reply.

I have included the day to day load/discipline chart above for the period to which you refer. I cannot disagree that I did not do proper rest weeks but instead used heavy v light days and different disciplines to give certain muscles a bit of a rest throughout the week. I tend to dislike the periodisation method as I tend to struggle with the last intense week of the cycle where I end up very achy & with compromised sleep quality. Instead I have tried to use Form, HRV, RHR & exercise intensity to avoid over training. During that period my run intensity was tempo but swim & ride intensity was light. I had thought/hoped that that might be a workable compromise to allow me not to neglect any discipline. Triathlon is difficult in trying to fit in quality sessions for the different disciplines. That is partly why I tend to avoid Z5+ sessions as that does tend to compromise other disciplines as well as raise my injury risk significantly. With running I tend to have to use hills to achieve Z5+ as speed increases my stride length & subsequently transmitted shock (over-striding at speed). With rides I seem just to lack the leg strength to get high intensity. I realise that I neglect strength work tending to rely on high resistance/hill run & hand paddle/fins with cardiac exercise to build any strength. To fit in weights would take cardiac exercise time away. Perhaps that might need to happen. Also lack of rest weeks could also be why I am weak. Then I could better follow a cyclical load pattern. However I am not really competitive or interested particularly in events/racing & so focus on health & stamina. I do admittedly therefore deliberately run/ride on tired legs as part of this stamina focus. I am in awe how competitive triathletes manage to fit it all in!

I am also aware that I am perhaps tending to anchor to past performance & hold the view that the body is generally stronger/more capable than the mind would have us believe. For example when Eddie Izzard did his month of Zwift FMs I decided to do a month of Sub 2 HMs (with hills, Alpe & Ven Top & final Sub 4FM) which was a stretch for me at the time & I was amazed to do it relatively comfortably. It did not really wipe me out as I am currently experiencing with lower training loads. I did sensibly ease back afterwards & swap to more cycling for a while in my defence. I did pick up a hip/groin strain in May 2020 but that was because I swapped to running on a manual TM & stretched my stride length a bit too far. Perhaps the chronic strain from January made me more susceptible but I did not feel that it was an obvious trigger.

I’m not altogether against your training methodology. The images are still rather low image when I view them so I’m guessing a bit, but what I see are two main things:
• There’s a lot of Z3+4 for this level of consistency. You might be better off with more Z1/2 that has a lower recovery cost.
• The number of days off started increasing. I’m guessing this was for recovery. Indications of an issue were growing weeks ago.

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Many thanks for your thoughts & time taken in replying. is a great site/forums for both generous individual advice & hopefully group learning from what others do.

I have probably addressed some of the issues in my reply to Gerald. Hopefully the shorter time span screenshot in that reply might give sufficiently high detail. If not then I can post a shorter time span.

I am tending to think that high volume, low intensity is perhaps as risky in terms of over training risk/chronic fatigue as lower volume, higher intensity cyclical training. To address this would mean a radical change in my training style & not something I want to try out before I am fairly sure that this is my mistake. As I said to Gerald I am perhaps anchoring to my previous ability to seemingly cope with high volume, low intensity. And to relying on RHR, HRV, Ramp etc to give indicators of over training. I am not particularly aiming to build to a high level level of fitness as in a target CTL. I mainly want to feel like I am maintaining a good level of fitness generally to justify my time investment i.e. averaging say 10hrs training per week & also to be relatively competent (not expecting to be competitive) in the three disciplines.

In terms of you saying that you felt that I was trying to raise my CTL quickly with hard efforts, that was not really my intention at all, quite the reverse in many respects as I explained to Gerald’s reply. I agree that there is quite a bit of orange/Tempo stuff as well as higher ATL/significant Ramping during the month of HMs. Quite a lot of orange stuff though is actually only just above the Z2 threshold which I tend to view more as a “fuzzy threshold” rather than a “cliff edge”. I do find it difficult to measure my thresholds as I am trying to use power rather than HR. However, my power thresholds are generally one zone (in 7 zone system) higher than my HR ones presumably due to HR lag in interval workouts & my ability to hit much higher power when running uphill than on the flat (my over striding issue). So if I had used HR as the ATL/CTL guide rather than power then that period you referred to would have come out quite a bit less intense than it might appear. I appreciate that this might sound like a functional exercisoholic (as opposed to cyclical binge exerciser) trying to justify their addiction! That is perhaps I might subconsciously tend towards drip drip exercise loading pattern rather than intensity (“binges”) with rest periods. No highs but no cold turkeying either.

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You say that you ride/run on tired legs. Have you considered doing a Z1/2 ride AFTER doing a harder run?

Many triathletes I have spoken to over the years believe it should only be done as “ride and run” and not the other way around. The benefit of reversing it, is to get the benefit of a harder workout (run) that has a more impact on the body compared to a low intensity ride that builds fatigue over time but makes the harder workout (run) even harder.

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That “fuzzy threshold” grew a bit too much fuzz over time. High volume, low intensity is probably not inherently risky but it does require respect.

I know Ultra-running coaches who agree with your methodology, but they are careful to recognise when the body isn’t absorbing. Think of the cost of recovery increasing exponentially as intensity increases above Z1, and as volume increases.

Thanks for your reply. I wanted to capture the acute & subsequent detraining phase hence I included a longer time span.

I have replied to Lukasz since your post and so this might answer some of your query about the amount of Z3/4. I did sort of appreciate the over training risk after my month of HMs & decide to detrain a bit without feeling as though I particularly physically needed to necessarily.

It does sound so easy to work out the thresholds in theory but as I explained I am struggling due to the power v HR load issue. I accept that power would suggest higher loading than HR & perhaps I am doing something incorrectly. I wanted to use power with running so that it correlated with using power in cycling but I am definitely less convinced by its worth. If I just ran flat & so faster to generate intensity then perhaps it would be easier but hills seem to completely mess thresholds up as I feel that my running threshold/critical power etc is a moving beast. On the flat my CP is probably 230-240W without risking injury. However at e.g. 8% gradient that seems far too low & so training zones feel that they need to shift up. I did try to get opinions on this on the Stryd FB site but got no clear resolution to how I might manage it better.

I have also swapped to using Xert in the last 6 months or so which has further complicated things. Trying to assess loads & recovery whilst doing multiple disciplines using their method is difficult not only due to different thresholds as mentioned but also trying to combine the physiologically different effects of multiple discipline to get a single freshness/recovery score.

I suppose that it would be easier to follow a properly formulated training plan but I dislike the usual duathlon/triathlon favouring of cycling. I appreciate that it is perhaps heresy to say this here but cycling is my least favourite discipline & done mainly to ease impact. I have tried in the past (honestly I have) to follow them but end up swapping running & cycling workouts around which defeats the science behind them. Also as previously mentioned I struggle with the intense weeks. That is the issue when I have tried 80/20 regimes. I can do it with running using hill intervals but cycling tends to end up being Z4 rather than Z5+ as I am just too weak I think. And adding in weights sessions would make doing three disciplines (none of which I would not really want to drop ideally) prohibitively time consuming or end up in serious exercise addiction. If I was to drop any it would be cycling (heresy I know) and then I would grieve the loss & the very expensive clothes horse (Wattbike Atom G2 with rockerplate)!

I have done that in the past and perhaps should go back to that more. I perhaps am underestimating the stress/impact of an easy running interval/cooldown in terms of recovery effect v easy “brick” cycle and treating all Z1/2 load as equivalent. It is certainly worth trying out. I do tend to do run/swim, ride/swim days rather than run/ride days. But lately my swims have tended to be more Z3/low Z4 probably (assuming my thresholds are accurate) so not a recovery session after the high volume/low intensity ride or run earlier in the day. Many thanks.

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I don’t think a formulated plan is essential. Many of the best ultra-athletes adjust day by day.

I get that. For some of us it’s very, very costly—physically and thus mentally and thus physically.

Keep in mind that 80/20 is by session. When translating that into TIZ it’s more like 90-97%/2-10%.

These have a huge load on the body.


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I do not think of Z2/3 as being “intense” but I take your point & have read others mention that exponential increase in recovery time needed though previously I would have regarded that only probably Z4+.

You are probably correct in that I am assuming that my RHR, HRV, Garmin data etc is reflecting whether I am absorbing rather than going with my gut feel or viewing lower/decreasing muscle tone as being recovery related versus a consequence of “doing too much cardio”. Having been a nurse I tend to favour objective measures/scientific data rather than trusting my gut. I am pretty indecisive generally (reading far more widely than is probably healthy for clear decision making) & so my mind tends to control how I physically feel (or my perception at least) & is easily swayed. But the Garmin data when combined with the heart issue is likely making the hard data unreliable especially at the moment. doesn’t help a data/theory nerd like myself either with such comprehensive tools at hand. Perhaps running “naked” is a way to avoid this. Cycling “naked” might chafe a bit too much though!

You are not alone. IME, most athletes underappreciate the cost of >Z2, and high volume Z2.

No wearable is able to detect the load in the tissues. There are blood markers that provide information, but unless you have access to a lab for regular testing you have to be very sensitive in your skills to listen to the body; this requires developing intution which is not the thoughts coming from the mind.

I tend to disagree actually. allows graphing of subjective wellness data. These help with reading between the lines, IMHO.

:joy: Good attitude! :call_me_hand:

I am very strange perhaps in that I prefer hills. Running up Alpe de Zwift & Ven Top was great although admittedly I did use gradient adjusted pace for the Sub 2 time rather than flat pace so you are indeed right that it was harder. I am still amazed at managing that month with little prep & seemingly little physiological penalty.

80/20 is a confusing title for the regime. I will have to read more about it to ensure that I do it properly if I decide to stick to that regime.

Just watching the Sub7/Sub8 Triathlon Challenge & feeling guilty at struggling with my training regime & loads. They are truly superhuman.

Thanks for all the advice.

I can’t answer your question as well as the other guys have done, but what I can say is that sudden fatigue hit me 4 weeks after my 3rd jab and then again 4 weeks or so after that. Took the advice of @Howie and went for a blood test. My bloods were OK, but the doctor said that there is a great deal of this sudden fatigue and that it is being taken seriously and is being tested and researched, but so far they haven’t found a reason for it.