Permanently exhausted... trying to do too much, or just exhausted by life?

I'm 48 now, and diagnosed, and I recognise what you're saying, both the feeling that I don't have the capacity that I used to have, and the contrast between fatiguing and energising activities. I also recognise the problem of trying to find a bar to measure it by, though maybe a little less so since my diagnosis (or rather the awareness I've gained since my diagnosis led me to peer-to-peer advice such as here.)

The fact that the fatiguing activities include social skills and sensory over-stimulation do make me suspect that what you're experiencing is burn-out from maintaining the self-control to function in environments that make a lot of demands on autistic traits. Left unchecked, this is the kind of fatigue that can build over time, and can lead to a much more serious shut-down state, where the brain forces rest by simply shutting down some functions. You might find this article about autistic burn-out a useful read - not all of it will necessarily apply to you, but it might give you some more clues about whether that is what you're experiencing.

Part of managing this, you've already mentioned - making time for the activities that re-charge you by giving those worn-out brain functions a rest. Brisk walks in the greenery do wonders for me too, but other interests and activities in a peaceful environment and which don't make social demands can be equally effective. Making it known that I can't be contacted at these times also helps; my phone, email notifications etc. get turned off when I'm recharging myself so that I won't get interrupted by a social interaction.

Not letting it build up is key to the problem, I think, so I try to find small ways to let out a bit of the stress throughout the day wherever possible. For example; at social occasions, I will now find excuses to sneak out for a walk around the block, admire the garden for a bit, talk to just one friend in the kitchen, or even just to sit on the toilet with headphones on for a while, rather than forcing myself to be present for the whole thing. I've found that most people are OK with just saying; "I'm a bit fried, just nipping out for a bit.", so mentioning autism isn't usually necessary. I also make sure that people understand in advance that me leaving early is no reflection on them, and have an escape plan prepared so that, as a last resort, I can bail out without embarrassment or needing help. I don't make silly excuses for this or for non-attendance any more; they just lead to social complications, so I'm honest that I just have poor stamina, but that I still appreciate invites, and do enjoy people's company when I'm up to it.

Spotting the early warning signs helps a lot, too. For me, it's when I notice that my understanding of conversation is faltering, when I struggle to find a word every other sentence, when background sounds start to dominate my hearing, hand-eye co-ordination starts to get sloppy, rising heart rate or butterflies in my tummy, etc. These may be different for you depending which traits you most struggle with, but generally speaking, you could call any of them signs of anxiety.

I do think that my tolerance has decreased as middle-age has come upon me, but it is also very variable depending on what's going on in my life; it's always worse when there are other sources of stress to contend with, or if I attend too many social events close together. However, managing it, and being honest enough about it to compromise with other people, have definitely helped a lot. Coping with a few little wobbles here and there is much easier than pretending that I'm fine until I have a huge crash that takes weeks to recover from.

I'm 48 now, and diagnosed, and I recognise what you're saying, both the feeling that I don't have the capacity that I used to have, and the contrast between fatiguing and energising activities. I also recognise the problem of trying to find a bar to measure it by, though maybe a little less so since my diagnosis (or rather the awareness I've gained since my diagnosis led me to peer-to-peer advice such as here.)

The fact that the fatiguing activities include social skills and sensory over-stimulation do make me suspect that what you're experiencing is burn-out from maintaining the self-control to function in environments that make a lot of demands on autistic traits. Left unchecked, this is the kind of fatigue that can build over time, and can lead to a much more serious shut-down state, where the brain forces rest by simply shutting down some functions. You might find this article about autistic burn-out a useful read - not all of it will necessarily apply to you, but it might give you some more clues about whether that is what you're experiencing.

Part of managing this, you've already mentioned - making time for the activities that re-charge you by giving those worn-out brain functions a rest. Brisk walks in the greenery do wonders for me too, but other interests and activities in a peaceful environment and which don't make social demands can be equally effective. Making it known that I can't be contacted at these times also helps; my phone, email notifications etc. get turned off when I'm recharging myself so that I won't get interrupted by a social interaction.

Not letting it build up is key to the problem, I think, so I try to find small ways to let out a bit of the stress throughout the day wherever possible. For example; at social occasions, I will now find excuses to sneak out for a walk around the block, admire the garden for a bit, talk to just one friend in the kitchen, or even just to sit on the toilet with headphones on for a while, rather than forcing myself to be present for the whole thing. I've found that most people are OK with just saying; "I'm a bit fried, just nipping out for a bit.", so mentioning autism isn't usually necessary. I also make sure that people understand in advance that me leaving early is no reflection on them, and have an escape plan prepared so that, as a last resort, I can bail out without embarrassment or needing help. I don't make silly excuses for this or for non-attendance any more; they just lead to social complications, so I'm honest that I just have poor stamina, but that I still appreciate invites, and do enjoy people's company when I'm up to it.

Spotting the early warning signs helps a lot, too. For me, it's when I notice that my understanding of conversation is faltering, when I struggle to find a word every other sentence, when background sounds start to dominate my hearing, hand-eye co-ordination starts to get sloppy, rising heart rate or butterflies in my tummy, etc. These may be different for you depending which traits you most struggle with, but generally speaking, you could call any of them signs of anxiety.

I do think that my tolerance has decreased as middle-age has come upon me, but it is also very variable depending on what's going on in my life; it's always worse when there are other sources of stress to contend with, or if I attend too many social events close together. However, managing it, and being honest enough about it to compromise with other people, have definitely helped a lot. Coping with a few little wobbles here and there is much easier than pretending that I'm fine until I have a huge crash that takes weeks to recover from.

Thank you Trogluddite, lots of really useful insights and warning signs in your comprehensive reply - very much appreciated :-)