Is there a way to monitor the air in my fitness class?
Not every facility will have a carbon dioxide monitor, but it’s worth asking your facility if they have one in the group fitness room and whether you can check it. If the carbon dioxide levels are below 600 parts per million (the closer to 500 the better), it’s a sign that the room ventilation is adequate for exercise. If the numbers start to increase, ask to open a window or door — or leave the class. When Dr. Marr was attending an indoor swimming pool, she noticed ventilation levels in the room were poor, so she left.