Her area of expertise is the role of sleep and the biological clock in human performance. She has worked extensively with organisations such as Air New Zealand, Helicopters New Zealand, South African Airways and Boeing Commercial Airplanes to help them understand and manage fatigue in their environment. She has also consults to the Serious Crash Investigation Unit and the Transport Accident Investigation Commission on the role of fatigue in serious incidents. Alongside her consultancy work she oversees a range of research projects investigating the relationship between sleep and physical and mental health. Leigh is also a contributor to the Coach Accelerator Programme run by High Performance Sports New Zealand; focusing on helping coaches better manage their sleep and performance and the sleep and performance of their athletes.