Back from a cold: when and how to start training again

November is here, and with it the official sneezing season. If you train, you know the dilemma well: three days into the tissues you are already eyeing your trainers, convinced that you are "not that bad really". Good news: there is now some data to help you decide with more than gut feeling (and impatience).

What the study measured

A research team prospectively followed 114 acute respiratory infections in athletic people, both amateur and professional, and published the results in 2026 in the British Journal of Sports Medicine as the AWARE X study. The interesting bit is that they did not settle for "I think it's a cold": they identified the virus behind each case with PCR tests and graded severity according to the International Olympic Committee consensus (mild, moderate or severe).

They then measured three points in the comeback. The median time to return to training was 3.5 days; to return to full training, 8 days; and to return to previous performance, 11 days. Mind the word median: it means half of the people took longer. In fact, the usual range for getting performance back was 7 to 14 days.

Three things that slow the comeback

The study found three factors linked to a slower recovery. The first was the bug itself: flu and COVID-19 meant a longer return than rhinovirus, the classic culprit behind the common cold. The second was how severe the symptoms were at the start: severe cases took considerably longer than mild and moderate ones. And the third is the one that concerns us most: amateur athletes took longer to come back than professionals.

The study summary does not explain why amateurs find it harder, so what follows is our own hypothesis: a professional has a medical team on hand and a life organised around recovery, while you keep going to work, sleep what you can and often come back too soon. Whatever the reason, the practical conclusion is clear: do not copy a professional's timeline.

First things first: training or sofa today?

If you have a fever, you do not train. Nor if you have whole-body symptoms such as aching muscles, chills or the kind of tiredness that glues you to the mattress. And if you notice chest pain, odd palpitations, breathlessness out of proportion to the effort or dizziness, the plan is not "give it a go and see", it is to call your doctor. Once your symptoms have settled into something mild and local (a runny nose or a scratchy throat) and you have gone at least a day without a fever, you can start climbing the steps.

The catch-up trap

The most common mistake is not coming back too early, but coming back in a hurry: cramming into one weekend everything you missed during tissue week. It is exactly the opposite of what works. As we explained when talking about how far to run on Sunday without overdoing it, sudden jumps in load are a bad idea at any time, and even worse when your body has just got over an infection. Lost days are lost; you do not make them up, you accept them.

Flu and COVID: more patience

If yours was flu or COVID-19, expect a longer timeline than for a common cold, because that is what the study showed. And if after a couple of weeks you still feel a tiredness that does not add up, get breathless on efforts that used to be easy or your heart rate shoots up for no reason, do not put it down to being out of shape: get it checked. A slow recovery is far more likely than anything serious, but that call belongs to a health professional, not your watch.

The upside of all this: in most cases we are talking about a few days or a couple of weeks. No season plan breaks because of that. It breaks when you rush back and relapse.