With it seeming very likely the world will still be battling the novel coronavirus next summer, one expert is concerned about how protective masks might exacerbate the impact of extreme heat expected during the Tokyo Olympics.

Before the pandemic's arrival, the heat and humidity of Tokyo's summers represented the biggest health concerns for organizers. But the need for protective masks during the games means previous plans to keep staff and spectators cool may be inadequate.

"Protective masks cover the mouth, and that makes it harder for the body to expel heat, raising the risk of heatstroke," said Masuji Hattori, a Hyogo College of Medicine professor who specializes in the condition.