I have never read of any physiological reason for taking rest breaks. That is in over ten years of reading forums.
Well, let me amend that: After a session is over, until the start of the next session, you ARE resting from further stress. But the body is not resting. It is in the process of healing the damage done in the previous session.
It seems to me the question is: How much time do you need between sessions and why?
There is only one way to make gains in PE, and that is to provide enough deforming stress to the erection-restrictive-collagenous tissues which restrain an erection. Either the longitudenal or lateral layers of the tunica, or the ligaments which may hold inner shaft against the pubic bone for many guys. That is it.
Of course, it is really neat that your unit still work after undergoing all of that required stress. A big plus. Therefore, you have to be careful not to overstress, and surely not overstress the soft tissues of the penis, the nerves, blood vessels, skin, smooth muscle, urethra, etc.
These soft tissues, communications, plumbing, protection, etc, do not restrict an erection very much, but are very important. They DO need some period of time to recover from same stresses imposed on the tougher collagenous tissues. Generally within a few hours after a normal session, they are ready to go for most guys, unless there has been overstress.
Next, you have to ask what happens when rest is incurred after deforming collagenous tissues. The answer is, they begin to heal, almost immediately. Deforming collagenous tissues produces crinellations (folds) in the collagenous fibers, much as seen when a rubberband is overstretched.
In healing, these crinellations are bridged over by new collagenous tissue, laid down by the body. In time, this forms a much stronger area, due to more mass, IF the crinellations are not pulled out.
Let me amend that: The new material will be laid down anyway, healing the area. You want the new material laid down in the extended state, not in the retracted state. You also do not want the new material laid across folds, making the area much thicker, but rather laid flat on extended deformed tissue.
Therefore, if you allow enough time for the new material to “set-up”, become strong, in the retracted state, it makes it much tougher to make new gains in the area, new deformations.
Conversely, if you are constantly riding fatigue, session after session, further stressing already deformed tissues, further deformation is easier on these weakened tissues. Your body WILL heal no matter what. You simply want the tough collagenous tissues to heal in the extended state, not in the retracted state. BTW, fatigue is a very good indicator of deformation. Pain is an indicator of injury.
Sometimes, guys DO overstress, overwork. They become very sore, sometimes even suffer pain. This is an indication by the body that an injury is possible, a tear. That is the only reason I know of to take time off, the threat of injury. But that problem is caused again by overwork. Not being smart.
But even if a guy is very sore, if he can hang even one set at greatly reduced weight, he can pull out the crinellations formed from previous micro-damage, and while probably not making further progress, can at least keep from making gains tougher. This minimal work will probably not risk injury.
The best method I have found to make gains is to slowly work up in stress until you are able to reach fatigue early in a session. Then continue hanging, or whatever, at reduced stress while in the fatigued state, always remaining relatively comfortable. If you have to reduce weight (stress) to more than half your max weight, it is best to stop the session. If you do this, it is doubtful you will overstress.
A consistant, dedicated, smooth program; same amount of time, or same number of sets, each day, is the best way to make gains. Problems occur when guys do a one day, intense session. The body must have time to adapt and grow. You cannot make tremendous gains from one session. Not going to happen.
Finally, I can tell you from anecdotal evidence from hundreds of guys, no rest DAYS produces much better, more consistant gains. I have had reports from hundreds of guys who were on an arbitrary schedule that contained rest days, and who had minimal or no gains. Then, when they switched to taking no days off from hanging, suddenly began to steadily gain.
Further, again from anecdotal evidence, I can say that it appears that two or more shorter sessions during the day is more beneficial than a single session of the same time period. This makes sense in that the crinellations would be pulled out more often, giving less opportunity for strengthening.
Now, sometimes a guy reaches fatigue, deforming tissues, and the tissues naturally swell. The outward swell of the tunica causes the shaft to pull back slightly. The shaft seems to shrink and may seem rubbery. This is simply a bodily reaction to the microdamage.
If you take time off, the swelling goes down, and the tissues are able to return to normal length, or even longer because of previous deformations, previous work. The rest did NOT cause any actual gain, but rather impeded future gains.
BUT, if instead of rest days, you were to simply cut back on the intensity of your sessions for a day or two, the swelling would still go down, tissues return to normal, and you would have the added value of having pulled out the crinellations during that time, thereby making more progress.
So while I am not in favor of ever taking rest days, if it can be avoided, reduced intensity days do have value.
There is a lot of other crap involved, but that is the jist. Probably much more than you wanted to know.
Bigger
OKAY FELLAS: I asked BIB/BIGGER the question being debated on this thread about rest days and rest periods. The above is what he gave me permission to post. This to me is what I will chart my PE journey on because this guy of any guy in PE has attained what we all want. He tells me he will not get into a brouhaha over his opinion. It is as it is and it is final in my book.