PUTAL, SLOVENIA - FEBRUARY 5: Davor, a 53 year old programmer writes code and works on computer while walking on a treadmill on February 5, 2021 in Putal, Slovenia. He had his veins in his leg bypassed and cannot stand for longer periods of time. As he is computer programer he usually walked 30km per day on average while writing code. Davor got infected with COVID-19 in September 2020, since then he can walk maximum of 4 km per day as he suffers the long term disease, leaving consequences on his ability to focus and to maintain the energy. After contracting the Coronavirus, some people suffer a chronic form of Covid-19, with symptoms that persist for months after infection including fatigue, breathing difficulties, shortness of breath, hair loss and skin rashes. The World Health Organisation (WHO), currently working to trace the origins of the Sars-CoV-2 coronavirus, has recognized long Covid-19 as a real pathology. (Photo by Matic Zorman/Getty Images)