A question

Hello Roei.

A quick answer from me:

First of all: Since you dont know about the basics of freediving a warning for you: Freediving is fun - however you should allways have someone wathing you, a buddy in the water who knows about basic freediving. Secondly you need knowledge about freediving to make it safe.

Your question is a basic question in freediving. You can find lots of info about freediving in general on this forum, and that basic info will answer your question. Have a look at the beginners section, theres a sticky thread with tons of information - some a bit outdated but still a good read.

If you got time and money also do a course, that is the best thing

In short I'd say it's because you spend energi going down + stronger diverespons + a mental aspect... More reasons might exist. But read a little on the forum, deeperblue is quite an information treasure....

roei - Actually, I find it easier to hold my breath at depth. You will find as you learn proper techniques that you might also experience the same. Being properly weighted and using the proper duck dive can get you down with very little energy. And as Baiyoke said, always train with a buddy.