Can you leave the board while its your move?

Was watching coverage of the Tata Steel tournament and it was mentioned that you are not allowed to leave the board while its your move. Was mentioned that one needs to talk to the arbiter to get permission first. 

Is this a FIDE rule? USCF rule? I've never heard of it before. 

What's really going to blow your mind is what if I were away from the board while the opponent makes a move? That does in effect mean I'd be absent from the board during my turn. 🌝

Events can have their own rules in addition to normal rated play rules for a given federation.

I hadn't heard of that rule either. It's probably designed to reduce the opportunity for electronic assistance. It must be either a FIDE rule or one established by the event...I regularly play in USCF tournaments and have never been advised of such a rule.

For the record, I never leave the room during my move, but occasionally find it necessary to stand up to relieve soreness in my lower back. In such cases I stay at the board and continue to decide what (all too often stupid) move to make.

Ok good, wanted to make sure it wasn't common knowledge because I haven't followed it and sometimes have gotten up when it's my move to go to the bathroom.

@WSama, I don't think the rule applies if you are not at the board when the opponent moves. In the tourney in question, the other player made a move to reach time control, and immediately the player whose turn it was got up to take a break. The opponent looked up at him, perhaps surprised, and the player on-move gestured in the direction of the arbiter (which the commentator explained he was going to ask for permission). 

I've never heard of this rule either. It isn't a rule I am used to: at least not for the USCF events I've attended. My guess is that Tata Steel event (individually) came up with this rule because those games were being watched (online via recording, chesstv, audience in person etc.) and it doesn't help the ratings if the player isn't even at the board. I would imagine that the reason for this rule is an aesthetic one like this for the viewers.

I concur. I don't believe it's a rule as it is more of a policy to improve aesthetics of the tournament. In all my years of USCF OTB play, I would routinely walk around the room at look at other boards. I was both thinking about my position, but stretching and enjoying the other games in progress as well. I would use that as an opportunity to see firsthand what some of my upcoming opponents might be playing against me. 

The USCF is probably the only modern country that does not implement this rule. In most country, you cannot leave the board (not just the venue) when on your time. NOR can you eat at the table, NOR can you write down your move before playing it, NOR do you offer a draw before having played your move. There are many small rules that the USCF does not implement during tourneys and franckly, it sometimes takes the fun out of playing there.