A renewed focus on fatigue in light of long covid means we now have a better understanding of the body-brain pathways that cause it, offering fresh targets for new treatments
Health 6 September 2025
By Dana G. Smith
Peter starin
IF IT feels like you have been running on empty recently, you aren’t alone. Amid the turmoil of the past few years, a bone-weary sense of tiredness has become a familiar part of life for many.
Fatigue might be the most universal experience of the pandemic. It is one of the primary symptoms of both covid-19 and long covid, as well as the burnout and depression that have accompanied the stress of the past two-and-a-half years. Even Zoom fatigue, exhaustion brought on by video meetings, has become a recognised phenomenon.
One silver lining of all this is that it has brought fatigue, both in its everyday and more persistent forms, to the forefront of the scientific agenda. For decades, fatigue was dismissed as a fuzzy symptom with no clear biological origin.
Now, research is revealing that it is the result of an ongoing conversation between the body and the brain about how much cellular energy is available. A better understanding of the many pathways involved is bringing hope for tackling it. With chronic fatigue affecting nearly 1 per cent of the global population (a number that could now be an underestimate due to long covid), and 25 per cent of healthy people reporting regular struggles with fatigue, finding new avenues for relief has never been more important.
There are many different drains on our energy that can act as triggers of fatigue. Exhaustion can follow a bout of flu, a hard workout, a long day at the office or it can be due to a post viral syndrome such as long covid. While these causes of fatigue are very …
