A day of rest … more critical in the Virtual Racing World? A HRV case.

A day of rest … more critical in the Virtual Racing World? A HRV case.

I phoned a great ultra-running buddy of mine in Hong Kong last week for a chat.  He and I, last August, ran in Chamonix, at the Ultra-Trail Mont Blanc 57km OCC (11,000ft elev.) race.  In our conversation, he said something that’s been on my mind since endurance athletes around the world have been forced into the new virtual-racing scene.

I asked my friend if he’s been training or competing in the virtual races. He replied, saying, ‘No, I’m training on the real thing, the real world.’  Knowing Hong Kong trails this did make me envious, but I went on to ask him whether he thought virtual racing was more comfortable than the real-world?   We both laughed it off and talked about other things.  However, this is precisely the thought that has been on my mind,

Do you think the Virtual Racing world is easier on you?  Hmm.

Do you think the simplicity of  ‘entering/starting a race’ could trigger a less serious attention to race-prep and race-recovery?

Any thoughts, that since entering a virtual race without all the overhead (travel time, accommodation, costs etc.) there could be a trend to over-frequent racing?

Do you think, the concept of ‘seasons’ will disappear, as racing becomes an always-on experience throughout the whole year?

Well, to be clear, I enjoy the experiences of Strava, Zwift and iFit virtual worlds, and the group rides-runs and races on Zwift and Ironman VR.  Clearly, virtual training-racing is here to stay,  and has embedded itself into the endurance athletes lifestyle forever.

Now – back to the question – of virtual racing, and whether it’s easier on you or not (vs. real-life racing).

I’ve been using Heart-rate variability (HRV) on and off since 2015, mostly as a proxy to understand my current stress-recovery levels. More specifically, I am using it to measure my rate of recovery, Also, factors that lower my HRV (weakened stress-response, overactive sympathetic nervous response), and factors that raise it (balanced sympathetic/parasympathetic nervous system tone).  This ‘variability’ is measured in milliseconds (ms), as you will see in the charts below.  Actually, it was really through HRV that SFuels first came into contact with Dr. Dan Plews, since he had been conducting so much research there.

Let me show you my HRV data (I use WHOOP Strap 3.0, 24×7 on my arm) across the first several weeks of Ironman VR racing, and at least for me how my body responded –

VR1 Race: HRV Response

Here is my daily data from March 30 to April 5, 2020. For the VR1 race (simulating a 70.3 race), I did my 5Km run on Friday night, 3rd April (after deciding over dinner to do the race 😊). I did the 90km bike, immediately followed by the 20km run – all on Saturday morning.

Thursday, Friday, and Saturday (blue dots – highlighted as ‘A‘ in the left chart below) were tracked by WHOOP as high ‘Strain’ days.  In WHOOP, ‘Strain’ is a calculated number, using your resting heart rate average, HRV data, actual training efforts, sleep, and other factors like alcohol, meditation, caffeine, etc. So it’s no surprise that my recovery-rate (green/yellow dots)  began to trend down on Saturday and Sunday (highlighted as ‘B‘).  You can see my HRV (highlighted as ‘C‘ on the right chart), also trending down.  My HRV dropped from over 90ms on Friday, to just under 60ms by Sunday.


Now these shifts in HRV would generally occur, whether you raced in the real-world, or raced in the virtual world. Actually, there is a genuine benefit of virtual racing, in that all the stress of packing for a race, booking flights, airports, car-travel, finding accommodation, race-registration, racking bikes, disappears in the virtual racing world.  You just get your gear on, head into the pain cave with your race nutrition (less if fat-adapted, and using SFuels😊)  and get started when you want.

However, it maybe this very thing, this simplicity, this frictionless experience that feeds a bigger watch-item for athletes – and that is, over-frequent racing.  It’s is just so attractive to race the next weekend again, and that’s just what I did!

VR2 Race: HRV Response

I know there is a whole play out there on doubling down on two races on the same weekend, or consecutive weekends. Indeed, this is happening in the ultra-running scene.  Maybe it is just my age, but that’s not something I’ve practiced in real-world racing – how things change in the virtual-racing world!

So, here is my data for VR2, a simulated Olympic distance race that was held the following weekend after the VR1 70.3 race.    Again, I ran the 3km on Friday night, and then the 40km bike and 10km run on Saturday morning. I use Zwift for biking, and NordicTrack/iFit for running (with Garmin).


It’s interesting to see that with lower strain on Sunday 5th and Monday 6th, my recovery-rate, rapidly moved back to recovered levels by Tuesday (highlighted as ‘A‘ on the left chart).  You can see my recovery returned to normal on my Tuesday HRV measurement, with it back in the 90ms range (‘B‘ on the right chart).

However, this is where you begin to see the fragility and difference of the nervous-hormonal system recovery, discreet from musculo-skeletal recovery.

On Wednesday and Thursday (highlighted as ‘C‘ on the left chart), I trained lightly, but you can see my HRV (highlighted as ‘C‘ on the right chart) dropped-down, and was unable to hold, or return to the healthier 90ms HRV level. I would also emphasize that I recorded an inferior sleep of 5Hrs (consistent with overactive sympathetic nervous response) on Friday night. So, Saturday morning arrives, and with poor sleep, a lowered HRV pre-race – I start my 40km bike, and complete my 10km run.  No surprise, everything crashes to red, with recovery-health in the 30-40% range (highlighted as ‘D‘ in the left chart). Again, you can see this in my HRV data (highlighted as ‘D‘ on the right chart), with measurement at ~55-56ms levels, which is about 25-30% less variable than my healthy-recovered self.

Discussion:  It’s more than ‘just’ the legs –

My training in nutritional medicine has my post-race recovery regime including high-dose whey protein isolates (70-80grams/day), high-dose Glutamine (~6-10gr/day), Vitamin C (~5grms per day), heightened sodium/potassium electrolytes, and all with a lowered carb, higher-fat diet. A lot of this is the basis of our SFuels product portfolio, like our SFuels LIFE bars, our SFuels LIFE, SFuels Train and Race products.

I’m not trying to give a sales pitch here on endurance nutrition. However, with this nutrition approach I was back in the backyard attending to our lawn and garden, both afternoons after racing – with very little soreness, just some general tiredness. Quality targeted nutrition, and lowered carb consumption will support rapid muscle (micro-tears, etc.) recovery, and lowered inflammation.  It will also support gut recovery, the issue here being heat triggered gut membrane permeability, resulting in systemic inflammation.  This is well documented in the research literature – but you can read our paper on ‘The Ultra Gut’ here.

I could highlight further nutritional compounds and herbal extracts which can support adrenal exhaustion and nervous system imblanace. These may be valid, however, I get to that in a follow-up paper. But, if we are to sequentially race weekend to weekend in this virtual world or even to race year-round, with no seasonal break, then I think there’s more we’ll need to pay attention to, than purely nutrition.  And that’s quality rest, and techniques to elevate your HRV back up to healthy norms (sympathetic-parasymathetic balance). 

Re-establishing Parasympathetic Tone: Breathing and Sleep

Stress in all its forms, is sensed by many bodily systems, but aggregates into a sub-conscious (be thankful for that) understanding in the brain, via the autonomic nervous system (ANS).  As earlier referenced, there are two sides to the ANS, the sympathetic (SNS) nervous system and the parasympathetic nervous system (PNS).  It’s the sympathetic side that is being heavily stimulated with all this racing, by elevating the heart rate, increasing blood pressure, shunting blood from the digestive system to the working muscles. Conversely, the parasympathetic system brings that blood supply back to the digestive system, it calms the body down, and enables quality rest, and sleep.  When our racing and training is so ‘frequent’ our SNS can become hyperactive, effectively leaving our parasympathetic nervous system weak, and unable to help the body recover.  Classic signs are heightened blood pressure, poor circulation to the digestive system, inability to get to sleep, restless sleep, or light sleep.

Now everyone’s different, their constitution, age, culture and current life-stress unique. So, for me – here is my weekly sleep data, the week following the VR2 race, and two weeks after the VR1 race –

sleeppost imvr2You can see here, that based on all my data being tracked 24/7, and the algorithms WHOOP runs on my data – WHOOP recommends that I need 8hrs 45mins sleep on Monday the 13th.  Here is where the downward spiral of an over-reactive SNS begins to show. You can see that I am increasingly unable to get the sleep required (grey line) and the sleep-debt (green line) continues to grow until I realized what is happening.

I needed to STOP, take a real-pause, a real break in training-racing. On Saturday, I did zero training, I walked the dog, I took a 1Hr midday nap, I had a spa, I rested inside most of the day. On Saturday night, I went to bed at 8.30pm (yes, that’s right) with no iPad, no phones, no books, no lights.  I did several minutes of 4-7-8 breathing at night and through the day, to work on resetting my PNS (detailed research study here).  I crashed on Saturday night and enjoyed almost 9hrs of sleep.  I won’t show it here – but it was a high percentage of quality deep and REM sleep.  Sunday, was also no training, just rest.

Sunday – my recovery number: ‘94%’.  My HRV, is trending back up (currently 74ms).

In this virtual racing world we are living in (it’s here for the long-haul), don’t be confused in thinking that you’re an invincible digital avatar on Zwift!


We need to remember that virtual racing is still blood, hearts, muscles, sweat, and one super-smart brain.  Like all of us, I want to be at my best when I face every starting line – whether real-world racing, virtual racing, or just going after my PRs.

Your body knows when enough is enough – so listen to it, and play it safe.  Watch your sleep patterns pay attention if you have difficulty starting sleep, restless sleep (try HRV app/cloud service like WHOOP), and also watch your digestive system (indigestion, reflux, loss of tone, etc.). These will be tell-tale signs that your SNS is over-hyped, and your downward spiral has begun.  Write this, all in the interests of you Going Longer.

See you at the starting-line team.  Go Longer – Team SFuels.

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