The effects of suborbital spaceflight stressors on populations with cardiac comorbidities (including with implantable cardiac devices): a review

Fewer than 30 people have flown on suborbital flight profiles, yet estimates suggest that 10,000s of people may take such flights in the next 10-20 years, largely due to the increasing interest in commercial companies offering these experiences. However, the physiological effects of these flights on populations with cardiac comorbidities are poorly understood, and there is little focussed research in this area. As such, regulatory authorities have limited information on which to base guidance for operations, suborbital vehicle manufacturers and experience providers. The need for such information also relates to life support and protection systems of vehicles, as well as informing the education and training requirements for the passengers. Additionally, members of the general public who are likely to be able to afford such flights may have quite different physiology and co-morbidities compared with the professional astronaut populations who have thus far experienced these flight profiles. Cardiovascular disease affects around 7.4 million people in the UK alone (British Heart Foundation, 2020), so it is likely that a significant proportion of suborbital spaceflight passengers may be affected by this. We believe that a systematic review considering the effects of suborbital spaceflight stressors on this population would be beneficial for the success of commercial spaceflight. To date, no systematic reviews have been undertaken to evaluate the limited data currently available on cardiovascular disease.