Read Team Danmark (in Danish), I have tried to translate it here below:
‘There is very little information on how the coronavirus affects athletes in hard training. But athletes and everybody else should not be doing extremely exhausting training at the moment, as this can possibly result in an increased risk of infections.’
‘Studies have been made in the past that support the theory that there can be a so-called ‘open window’ after very hard training (ie extremely exhausting training) where the immune system may be weakened in the hours after training. The theory is that you after hard training is more susceptible to infections, and the theory is supported with studies on marathon runners, which show increased prevalence of respiratory tract infections in the days following a race.’
‘That is why Team Denmark recommends that you do have extremely hard practices during these weeks and that you as always are careful with regards to overtraining. This advice is regardless of whether you have contracted the coronavirus or not, explains the Team Denmark director, Lone Hansen.’
I (RÃ³kur) would like to add to this story, that any alternative training that you start doing now in principle is something that your body is not used to, and that you, therefore, have to then be even more careful.