Inclusion Criteria:  Male or Female, aged 18 - 35 years old. Exercise at least three times a week on a regular basis. Participant is willing and able to give informed consent for participation in the study.  Exclusion Criteria:  Known to have a significant acute or longstanding medical illness that limits their exercise capacity. Develop symptoms of anosmia, cough or fever between agreeing to participate and completing the exercise, suggesting they may have developed COVID-19.