Been doing some reading and came across this:
Although air movement is very beneficial for our plants, there also negative effects of too much air movement especially with your more mature plants. If leaf surfaces are cooled too much, your plants leaves can literally curl up. This unfortunately reduces the amount of active photosynthetic material on the leaves. Extensive strong air movement can cause your plants leaves stomata’s to close up, as your plants will try to alleviate any water loss, thus ultimately this process will stop the exchange of oxygen and carbon dioxide, leading to reduced or stopped photosynthesis.
Am I the only one that didn’t know this?! Argh. Well. Definitely room for improvement on the next grow!