Lettie’s research interests span the effects of exercise on immunity, inflammation and infection in the general population and those with specific long-term conditions, to the impacts of exercise on immune cell function and infection risk in elite athletes. She has recently been awarded project funding from Heart Research UK, the National Ankylosing Spondylitis Society, and Yakult Honsha. Lettie retains her interest in performance sport and collaborates with the English Institute of Sport on joint-funded projects aiming to maximise performance health.