If, possibly due to some sort of nuclear war, brain-eating zombies emerge and try to take over the planet, one of the first people they'll make a beeline for is three-times Olympic rowing coach Terry O'Neill. This is not just because of his collection of Country and Western albums, but as he knows, like, loads about indoor rowing, his brain is necessarily bigger and more nutritious than your average punter. In case this scenario does come to pass, you'd best send your questions into [email protected] quicko. James Thomas: I tend to row outdoors on the patio all the year round. During the recent big freeze I continued to do this and noticed a burning sensation in the lungs after a good session. I find this sort of bracing, but have been told (minus the scientific explanation) that it may be causing some mild damage to the lungs. Surely not? Terry O'Neill: When you breath normally through the nose several things take place. Firstly, there are a number of filters in the nasal passage that stop particles entering the lungs. The other thing that happens is that during the passage of air it is warmed up and if the air outside is dry then moisture is picked up.When you exercise, the tendency is to breath through the mouth and this bypasses the filters. If the air is dry this will lead to throat irritation and could lead to unwanted particles entering the lungs. Depending on what these particles might be, it could lead to lung infection. However, this applies regardless of air temperature when breathing through the mouth. When air enters the lung there is a difference in the partial pressure between the oxygen in the lungs and the carbon dioxide in the blood. Via the process of osmosis, the oxygen passes into the blood across the lung membrane and the CO2 passes in the other direction. If the air is very cold when it enters the lungs then this could affect the partial pressure in the lungs, which in turn would affect the process of osmosis. The effect would be a feeling of breathlessness leading to the need to gulp in more cold air compounding the problem, as it is not the air entering the lungs but the lack of oxygen entering the bloodstream. This could be the cause of the burning sensation and it may last several days seeming to be an infection.As with all medical questions we recommend you check with your doctor if you are in any doubt.