Well, long rests relate to natural healing, witch does not occur on the Astral Plane, so not really. As a DM you could personally rule otherwise though.

Time variance is a whole other matter, for witch there's no defined answer on the source books in relation to the Astral, so any DM can do as they like.

Quote from gsas93 >>

Well, long rests relate to natural healing, witch does not occur on the Astral Plane, so not really. As a DM you could personally rule otherwise though.

 That's not correct. Natural healing occurs just fine on the astral plane.

Quote from SagaTympana >>

That's not correct. Natural healing occurs just fine on the astral plane.

For instance, if you take a long rest on the astral plane, there is no reason to think you would not regain your hit points as long as there was not some unrelated effect preventing you from doing so.

Quote from SagaTympana >>

Quote from gsas93 >>

Well, long rests relate to natural healing, witch does not occur on the Astral Plane, so not really. As a DM you could personally rule otherwise though.

 That's not correct. Natural healing occurs just fine on the astral plane.

I provided the quotes from the official books a few comments before, witch say it does not occur at all, both on 3.5e and 5e. If the official books are not official lore enough in your point of view, then I guess nothing more can be said.

Quote from TexasDevin >>

Quote from SagaTympana >>

That's not correct. Natural healing occurs just fine on the astral plane.

For instance, if you take a long rest on the astral plane, there is no reason to think you would not regain your hit points as long as there was not some unrelated effect preventing you from doing so.

Well I did provide the official books quotes witch say you can only regain hit points in the Astral Plane through magical means, so there is actually an effect preventing it.

Of course, that doesn't mean a different magical effect provided after beeing in the Astral Plane could not replace that effect though. That's why I would agree with Haravikk's strategy with the catnap spell for instance. Another idea could be the magical effects of a dead God body, witch the official books on both editions state to be able to overwrite the effects of the Astral Plane, but that would deppend on the particular dead God body, since each has its own effects.

Quote from gsas93 >>

Well I did provide the official books quotes witch say you can only regain hit points in the Astral Plane through magical means, so there is actually an effect preventing it.

 You provided 3rd edition book quotes. This forum is for 5th edition. The rules of older versions of the game are not relevant. There is no such rule in the current edition of the game, the one this forum is about.

Quote from SagaTympana >>

Quote from gsas93 >>

Well I did provide the official books quotes witch say you can only regain hit points in the Astral Plane through magical means, so there is actually an effect preventing it.

 You provided 3rd edition book quotes. This forum is for 5th edition. The rules of older versions of the game are not relevant. There is no such rule in the current edition of the game, the one this forum is about.

I provided 5th edition quotes as well, but I can do so again, if you didn't see those. I'll also add some others I only referenced but did not quote.

"Creatures on the Astral Plane don’t age or suffer from hunger or thirst. For this reason, humanoids that live on the Astral Plane (such as the githyanki) establish outposts on other planes, often the Material Plane, so their children can grow to maturity."

5e Dungeon Master's Guide (page 47)

"The Astral Sea, like Wildspace, is a void; however, it is not an airless one. Here, you can breathe normally and exist indenitely, never aging and never needing food or drink. You can propel yourself through the Astral Sea with the power of your mind alone, though many astral voyagers wisely travel in well-armed ships, for this place is the home of a host of fearsome creatures. Here travelers might meet the petried hulks of dead gods and swirling pools of color that serve as portals to other planes of existence."

2022 Spelljammer Book - Introduction

"Because these dominions are part of the Astral Sea, they are timeless; nothing ages there, and creatures can survive there indefinitely without food or drink."

2022 Spelljammer Book - Astral Dominions and Dead Gods

"The Astral Sea not only has gravity (see “Gravity Planes” above) but also breathable, comfortable air. But is the air real, or does this heavenly realm merely trick creatures into thinking they’re breathing? In the Astral Sea, one can never be certain. All that really matters is that a creature can survive indenitely in the Astral Sea, never aging and never feeling hunger or thirst."

2022 Spelljammer Book - Traversing the Astral Sea

There's also many references to the previous spelljammer books on previous editions and the planar handbook as well, regarding stuff like how long travel takes in the Astral Sea, how gravity works, the composition of githyanki crews on pirate ships, how big a crew can be maintained on such voyages in relation to the ship size and such. Both on the rule books and the adventure books. The most recent books are quite vage on several subjects that have been defined previously though. We end up having to find bits and pieces scattered between several small books instead of having a single complete source for it. The best thing that could happen really would be a new and updated release on the planar handbook with all that stuff compiled in a more comprehensive guide.

Not a single thing you quoted references long rests. 

It mentions not needing food or drink and not aging. But this is not what long rests are for. I mean warforged don't need to eat or drink and don't age. Epic level offers boons of ageless immortality. Several features may allow you to not need food or drink. Some even let you go without needing to sleep.

Yet, regardless, a long rest can still be taken to rest, heal and regain expended energies and resources.

So, again, you've still not quoted anything at all that mentions not needing a long rest in the Astral Plane.

Quote from Cyb3rM1nd >>

Not a single thing you quoted references long rests. 

It mentions not needing food or drink and not aging. But this is not what long rests are for. I mean warforged don't need to eat or drink and don't age. Epic level offers boons of ageless immortality. Several features may allow you to not need food or drink. Some even let you go without needing to sleep.

Yet, regardless, a long rest can still be taken to rest, heal and regain expended energies and resources.

So, again, you've still not quoted anything at all that mentions not needing a long rest in the Astral Plane.

I quoted the citation of the timeless feature on the 5th edition spelljammer book, witch does the same as saying time does not flow, therefore long rests do not work regardless. I never said you'd never need resting, I said the Astral Plane is timeless and that is the reason why natural healing does not happen, as well as poisons do not take effect while on the Astral. I also provided alternatives through witch to generate magical effects that provide the oportunity to rest (spells, dead gods) as well as the references of those examples, such as githyanki hiring clerics and such. All of those are within the spelljammer books and dungeon master's guide.

You are misinterpreting "timeless" to mean "nothing advances in time" or "time does not advance".

That is not what is meant by the description. The description is to detail creatures do not age. The environment does not deteriorate over the ages, etc. It's not to say time ceases to exist for everything within. If that were the case, then the moment you enter you'd be frozen in place forever - because you, being part of time, would be unable to progress forward in time there. So the question is, do you think the intention was for campaigns to effectively stop, roll new characters ending, the moment the party steps within?

No.

At the end of the day you are inventing an a rule from your inference and forgetting that a rule does what it says. There is no rule that says "while here, you cannot benefit from healing from a long rest". 

If time did not exist in a creature while there then they'd be unable to benefit from a long rest - be it healing or regaining spell slots etc. Yet, spelljammer books introduces races that spend many years there. 

Let's provide another example about "no natural healing". This would mean no wound ever closes. No bleeding stops. Every tiny little nick, a mere papercut, could pose a serious risk to survival. Cut an ankle? Didn't check coz it didn't really hurt and you barely noticed? Now you be leaking blood, non-stop. What of battles? What if you get many cuts and bruises (noting that a bruise is basically internal bleeding - blood vessels that are broken and leak under the skin), well with no natural healing that bruise is just going to swell, and swell, and your cuts will run and run. 

I don't think it was intended that minor injuries would risk your life. I don't see some abundance of healing potions and everyone having cure wounds in this spelljammer book, so either WotC decided 'let's make the most brutal hardcore and dangerous D&D adventure in history' or your over-fixation on a descriptive word choice of "timeless" is not what you think it is.

Dunno 'bout you but I be going with the latter.

So unless you can actually quote the RULE that SAYS creatures cannot gain natural healing in the Astral Plane, then you've got nothing, sorry.

Quote from Cyb3rM1nd >>

You are misinterpreting "timeless" to mean "nothing advances in time" or "time does not advance".

That is not what is meant by the description. The description is to detail creatures do not age. The environment does not deteriorate over the ages, etc. It's not to say time ceases to exist for everything within. If that were the case, then the moment you enter you'd be frozen in place forever - because you, being part of time, would be unable to progress forward in time there. So the question is, do you think the intention was for campaigns to effectively stop, roll new characters ending, the moment the party steps within?

(...)

 

 That logic is actually wrong, since the Dungeon Master's Guide specifies that the Astral Plane is a plane of thought, ether and spirit. Similarly to the outer planes, witch are also planes of thought, ether and spirit. Where souls would go for the afterlife. Those things do not need time to pass or even exist.

I believe you are confusing the concepts of the Astral Plane (a "between place" for minds, souls and spirits) and the Phlogiston or the Flow (the thing that exists on the Material Plane between all crystal spheres). The crystal spheres, the phlogiston and the flows between the spheres are all in the Material Plane, witch most certainly needs time to exist. Those are more akin to the Wildspace in that fashion. The Astral Plane on the other hand is a spiritual thing, where time is meaningless and the experience of time is exclusive to each creature that traverses there.

From that point forward, everything else you said is based on a conceptual mistake, you see. And if there's no time, there's no long rest.

Quote from Cyb3rM1nd >>

 

(...)

Let's provide another example about "no natural healing". This would mean no wound ever closes. No bleeding stops. Every tiny little nick, a mere papercut, could pose a serious risk to survival. Cut an ankle? Didn't check coz it didn't really hurt and you barely noticed? Now you be leaking blood, non-stop. What of battles? What if you get many cuts and bruises (noting that a bruise is basically internal bleeding - blood vessels that are broken and leak under the skin), well with no natural healing that bruise is just going to swell, and swell, and your cuts will run and run. 

(...)

That's precisely the reason why the githyanki city is located on a dead god body, witch has its own magical effects overwriting the general effects of the Astral. That's precisely why the githyanki use settlements on the Material Plane, so that their children can grow to maturity. That's precisely why they hire clerics.

That's also the reason why spells like the catnap spell exist. Same as the reason why it'd be a good idea to stop in between different Wildspace areas for resting and trading. There's a lot of content related to that.... Based on all those things I see no reason to bother discussing the definition of timeless...

Nope, still not seeing the quote that says "creatures cannot gain natural healing in the Astral Plane".

"The Astral Plane is the realm of thought and dream, where visitors travel as disembodied souls to reach the Outer Planes."

5e Dungeon Master's Guide

"Because these dominions are part of the Astral Sea, they are timeless; nothing ages there, and creatures can survive there indefinitely without food or drink."

2022 Spelljammer Book - Astral Dominions and Dead Gods

Those two are the only two quotes you really need to understand it. I'm sure everything else I quoted and/or referenced you can certainly find yourself if you actually have the books... That beeing said, believe what you will, it'll be a DM rulling anyway. :D

And again, neither of those state you can't benefit from long rests or natural healing.

And I do have have the books. All official 5e ones, including spelljammer. Not a single one states Astral Plane restricts rests or healing in any way. 

I think the best evidence that the rules that govern biological processes on the Astral are found in the Githyanki entry of Mordenkainen's Tome of Foes, 'Only the Best Survive':

"The githyanki raise their young in hidden crèches that they construct in far-flung places on the Material Plane. Such measures are necessary because birth and growth are impossible on the Astral Plane, whose occupants don’t age."

That said, there doesn't appear to be anything in 5e to suggest healing doesn't work as normal.  In fact they changed magic to work normally on the Astral, essentially making it just like anyplace else and robbing it of its uniqueness.  Overall 5e design is meant to make everything easier for players, or at the very least, equally not terrible.  Being a cleric who can't cast spells on the Astral is kind of lame for the player, I suppose, but it's clearly not the lack of Divine and Arcane spells designations driving the decision, as the plane is now littered with 'Astral Dominions'.

So, as in every other place in 5e, the Astral is another location where it's all but impossible for PCs to actually die, in practice, (except at low levels, that probably shouldn't be floating around in the Astral for the most part.)

Quote from gsas93 >>

"The Astral Plane is the realm of thought and dream, where visitors travel as disembodied souls to reach the Outer Planes."

5e Dungeon Master's Guide

 

"Because these dominions are part of the Astral Sea, they are timeless; nothing ages there, and creatures can survive there indefinitely without food or drink."

2022 Spelljammer Book - Astral Dominions and Dead Gods

Those two are the only two quotes you really need to understand it. I'm sure everything else I quoted and/or referenced you can certainly find yourself if you actually have the books... That beeing said, believe what you will, it'll be a DM rulling anyway. :D

 As long as we're bumping this, I wanted to illustrate that this is an example of "A + B = C" logic, which is by definition not RAW or even necessarily RAI.

It's also incorrect because it says the realm is timeless. The only mechanical way that rubs off on the creatures within the realm is explicitly stated.

If you wish to houserule things because you feel the mechanics would better reflect the lore, than feel free to do so. But you shouldn't cherry-pick rests as the only casualties of this logic - the bodies of all creatures should completely freeze when they enter the plane. No movement, no weapons, no spell components, no physical actions can be taken. The PCs become formless entities of thought with entirely different rules governing how they move, how they perceive, how they interact with the world, and basically every other aspect of the game. It's the Matrix in D&D. Have fun writing that up.

It's really not cherry picking.  This is something the designers changed about an existing setting in the game when they updated editions.  You have a predetermined outcome you've decided on and I actually agree with your conclusion, but it is a surprising removal until you consider the designer's intentions.  Streamline rules, empower players, no "traps", cross-setting versatility.  In light of these design requirements, the rule seems obvious, still sad to see it go.

And, for the record, parsing how all of those different things work is kind of fun.   

Your speed is a mental effort, so really you never are moving. If anything, the plane is moving at your will to decrease the distance between you and your destination.

Freezing requires heat exchange, it's not a given and the average kinetic energy of the medium, whatever it is, of the Astral is a temperature of around a human(oid) body per 5e which describes it as like a moderate day in a temperate region.  It's really appropriate when you see all the aquatic inspired life, because it's almost like you're in a luke-warm bath.  Spells that exchange heat still work.   You will still freeze from cone of cold.  I wouldn't allow a nonmagical bonfire to be lit though, which might explain why githyanki have always been heavily involved in pyromancy. 

Time exists on the Astral as a series of states, definitively things change from one state to another.  Rather, the specific issue that dictates what happens on the Astral is what happens by will and otherwise.  A mental effort needs to be exerted for anything to move, change, transpire on the Astral.  Psychic winds, for example, move because they will manifested.  Biological processes, generally speaking aren't.  You could argue about sympathetic and parasympathetic activity as it relates to the will or mind, but neither is happening if the process isn't connected to something like a brain.  Look again to the githyanki, and their psionic attributes, or to the Astral projection that allows travel through the Astral by creatures in other planes.  The chief difference between those travell9ng with a silver cord and those on the Astral plane, proper is the fact that the body has joined the mind, which is what moves about and changes states in the Astral.  The body is just along for the ride: another reason healing and biological processes are separate from general Astral Plane mechanics.

Which brings us to perception, which is not achieved by light hitting a retina or pressure fluctuations trsvellong through a medium and detected by effected corporeal tissue, it is anwholly separate experience mapped onto those sensory pathways, which is why an astrally projected creature can perceive despite their body not being on the Asteap plane at all.

I think the rule is the rule.  I ultimately decided not to houseruke differently.  I just had a player stick a rift in a handy haversack and decided they ended up on the Astral, now i am looking at what that means for them now that their here.  I'm going with 5e rules for it. Healing is totally normal, but it really doesn't make sense.

Incidentally, I unless there's an errata injavent seen yet for it, the rules of Astral mechanics seem to be at odds between sources in 5e.  Either movement is 3x Int score (DMG) or 5x Int score (SJ:AiS).  I think there are some rough edges on the Asteal Plane mechanics, is all I'm saying.

Now processes aboard a apelljammer, there's an interesting question. Seems most things work more normally around gravity planes. Could be the presence of mass functionally creating some temporal effects.  Still necessitates will.  

Now here's a mechanical question: the fishing mechanic.   The table describes things as being edible, implying they could be eaten. It never says when, though.  If there's no biological processes at work, it won't rot, so you can take your catch with you as long as your journey through the Astral lasts, but if there are no normal biologicalprocesses, what would happen if you tried to eat it while on the Astral Plane?  

Questions like this are what make unique settings fun to try and immerse oneself and do some world-building and roleplay. There shouldn't be a specific rule for all of these things. The more rules and 'options' the desifners present, the more limited we are in how we play the game - exceptions procong rhe rule. 

Instead, we should figure out the fine rules if our worlds ourselves.

"This is how things are, so it implies that..., from which we can infer that...," and so on.  That is the fun of world building and really what a role playing game setting should encourage.  You just dismissed it like it was undesirable. If you're not into worldbuilding or roleplay, may i suggest chess? 

While I do like the old lore, I choose to use the new mechanics fie 5e, for now, which do pretty clearly indicate the Astral, in 5e, is more or less just another place.

"Survival on the Astral Plane

Survival is relatively easy on the Astral Plane – the realm is timeless, so characters need not eat, drink, breathe or even sleep if they do not want to. Decay, illness, even the onset of poison is halted on the Astral Plane. Dying here takes effort"

"Timeless: Age, hunger, thirst, poison, and natural healing don’t function in the Astral Plane, though they resume functioning when the traveler leaves the Astral Plane."

Source: 5e SRD

Classic Play – The Book of the Planes, copyright 2004 Mongoose Publishing Ltd. via 5eSRD.com

So, it looks like I was wrong. Legally, i can't make up an Astral plane where biological processes like healing don't function, kr Wizards can sue me because it infringes on the rules of 5e, even though it's not in any of the books, apparently. Lol. (Unless I reference the OGL, etc...)

Quote from Wile_E_Coyote >>

"Survival on the Astral Plane

Survival is relatively easy on the Astral Plane – the realm is timeless, so characters need not eat, drink, breathe or even sleep if they do not want to. Decay, illness, even the onset of poison is halted on the Astral Plane. Dying here takes effort"

"Timeless: Age, hunger, thirst, poison, and natural healing don’t function in the Astral Plane, though they resume functioning when the traveler leaves the Astral Plane."

Source: 5e SRD

So, it looks like I was wrong. Legally, i can't make up an Astral plane where biological processes like healing don't function, kr Wizards will sue me bw abuse it infringes on the rules of 5e, even though its not in any if the books, apparently. Lol.

I looked through the 5e SRD and that text is found nowhere in it.