As all freedivers with a minimum of experience know, water conditions greatly influence our performance, and a depth easily reached in the Red Sea is not as easy to reach in the Mediterranean, and even more difficult in a lake.
But what specifically influences performance?
The factors which condition our performance are many, some are suggestive, a classic example of which is low visibility. Almost all freedivers, when diving with low visibility (lower than 5 meters), do not have the same abilities as in clear, crystalline waters – seeing the finish point always offers reassurance, especially when we’re not expert divers. It’s a bit like driving in the fog or with low visibility. When at the wheel, as well as going slower, we are less relaxed and sure, and with freediving more or less the same thing happens.
There are also objective limits which change our performance. Personally, I mostly suffer water temperature and current. In cold water the feeling of well-being definitely decreases. Feeling the chills reduces our relaxation a lot and, consequentially, our performance. To be comfortable in cold waters we must have thicker wetsuits, but this means changing our weighting, wearing more kilos which makes our way of staying in the water less natural as a consequence.
With the current, however, it is harder to maintain a good descent trajectory, and going down along the cable takes double the effort. As well as a greater effort to descend, it is also harder to win against the force of the current which tends to move us away from our point of reference. In cases where there is a particularly strong current it is not possible to descend.
From my experience in the Mediterranean, aside from in exceptional circumstances, the current is usually found at the superficial layer of the sea, that which goes from the surface down to 30/35m.
Another limit to a freediving descent is rough sea. This condition means the relaxation and breathing phase is difficult. Particularly agitated sea makes our discipline impossible.
GG
Gianluca
14th November 2017
Italy 
