Magnus Cort’s Covid-19 positive heart rate and respiratory rate changes revealed by Whoop

Magnus Cort Nielsen (EF Education- EasyPost) was pulled from the Tour de France before stage 15 on July 17 after returning a positive test for Covid. Data from his Whoop band has revealed interesting changes to his biometrics after contracting the virus. 

Fitness and health tracking brand Whoop is now on the fourth iteration of its wearable band that monitors key health metrics, including heart rate, Resting Heart Rate (RHR), Heart Rate Variability (HRV), and Respiratory Rate (RR) - these metrics can be used to help riders predict their state of recovery and avoid overtraining, as well as “identifying signs of illness sometimes before you actually feel sick,” according to Whoop. 

Whoop has shared data which shows the five days leading up to Cort’s positive Covid-19 test, which reveals how the rider’s RHR slowly increased gradually up from 37bpm, before dramatically spiking up to 47bpm on July 17 - the day he didn’t take to the startline for stage 15. 

The Whoop data also showed a significant decrease in his HRV, which dropped steadily from 99 to 87 from Stage 11 to Stage 14, before then plummeting from 87 to 61 overnight on July 16. 

A bump in RR from 14.5 average breaths per minute to 16.5 was also picked up by Whoop’s data. 

Whoop acknowledges that RHR and HRV can meaninglessly change by a few beats per minute from day to day, having a relatively low "signal to noise ratio". On the other hand, median RR has a much greater "signal to noise ratio", making this metric comparatively “very easy to interpret and trust” says Whoop.

An increased respiratory rate can be a sign of Covid-19 as the virus infects the alveoli. Whoop explains on its site: “Alveoli are the blood/lungs interface at which oxygen passes from the lungs to the blood and carbon dioxide passes from the blood to the lungs. Without functioning alveoli, each respiration does not remove as much carbon dioxide from the blood or provide as much oxygen to the blood as it used to. To make up for the loss of efficiency per breath, the body is forced to undergo more respirations to provide the same blood oxygen supply.”

Up until this point this year’s Tour de France had been going very well for the 29-year-old. The Dane claimed the king of the mountains jersey for the first week of the race after being in the breakaway on both road stages in Denmark, and then he sprinted to victory on stage ten, the second Tour victory of his career. 

He even admitted himself: "I couldn't have dreamed of a better Tour so far for me than this.” Alas, it wasn’t to be anymore…

The whole Tour de France peloton underwent testing on Sunday evening. 150 riders tested negative on the lateral flow tests, and so have been free to continue. Only two riders test results have been sent for further examination, and both of these riders in question are outside the top 20 of the race’s overall classification.