1. Wits Sleep Laboratory, Brain Function Research Group, School of Physiology, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
2. Faculty of Health and Medical Sciences University of Surrey Guildford Surrey UK
3. Department of Human Biology, Health through Physical Activity, Lifestyle and Sport Research Centre & Division of Physiological Science, Faculty of Health Sciences University of Cape Town Cape Town South Africa
4. Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
5. Faculty of Health and Life Sciences Northumbria University Newcastle‐upon‐Tyne UK