One in eight people who were admitted to the hospital with Covid had heart inflammation and damage to the body's organs.
Some people who had Covid were left with long Covid, a condition that has been called long Covid.
Some experts have warned that Covid could result in a generation affected by disability and that fewer than a third of patients who have ongoing Covid symptoms after being hospitalized feel fully recovered a year later.
Covid can take a toll on a range of organs according to researchers who are tracking the progress of patients who were treated in hospital.
They say the severity of ongoing symptoms appears to be linked to the severity of the Covid infection.
Prof Colin Berry, of the University of Glasgow, said that even fit people can suffer severe Covid-19 illness and that members of the public should take up the offer of vaccinations.
Berry said that the study shows that there is evidence of abnormality at one to two months post-covid and that it ties in with the likelihood of ongoing health needs one year later.
159 people were hospitalized with Covid between May 2020 and March 2021.
Patients were given questionnaires to complete after being discharged from Covid, and the team carried out a range of scans and blood tests. The results were compared with a group of people who had not had Covid.
The authors write that the people who had been hospitalized with Covid showed several anomalies, including in the results of their scans.
One in eight of those who were hospitalized for Covid were found to be very likely to have myocarditis by experts. Dr Andrew Morrow from the University of Glasgow said that this led to a lower health-related quality of life, greater illness perception, higher levels of anxiety and depression, and lower levels of physical activity.
The likelihood of myocarditis was higher for healthcare workers and those with acute kidney injury.
Morrow said the findings reinforce the importance of the vaccine programme and novel treatments that have reduced the number of severe cases of Covid-19.
The results show that those who had been hospitalized with Covid were more likely to need outpatient secondary care or be referred for symptoms consistent with long Covid, with death and re-hospitalisations also much higher in this group.
The study provided important insights into the prevalence of clinically adjudicated myocarditis and its association with long-term symptoms in those hospitalized with Covid early in the Pandemic.
The presence of persistent heart inflammation was not assessed during the later follow-up, few participants had received a Covid jab, and the Covid variant involved were unlikely to be the Omicron lineages that are prevalent today.
Current-day estimates of myocarditis may differ from this study due to differences in vaccine effects.