Mental health work asks people to sit closely with other people's distress for a living, and how sustainable that becomes depends on the systems around them.
Work that asks a great deal of a person
Mental health work, clinical and non-clinical alike, asks people to sit closely with distress, uncertainty and sometimes danger, day after day, often while carrying a heavy and unpredictable workload. Reception staff absorb difficult calls before anyone else does; support workers hold steady through crises; clinicians make judgement calls that matter a great deal to another person's life. This is demanding in a particular way. The tiredness that follows is not only physical, and it does not always lift with a good night's sleep or a weekend off.
Burnout is a systemic problem, not a personal one
The exhaustion, detachment and loss of a sense of effectiveness that can build up in this kind of work is often called burnout, and it is worth being clear about what it is not. It is not a character flaw, a lack of resilience, or evidence that someone has chosen the wrong career. It tends to arise where demanding emotional work is combined with heavy caseloads, unclear expectations, little sense of control over one's day, and not enough time to reflect on what the work has involved. Related to it, but distinct, is the strain that can come specifically from being repeatedly close to other people's trauma, which can leave its own mark even on someone who is otherwise coping well with workload. Neither is fixed by telling the individual to try harder to look after themselves, though personal habits do matter.
What tends to help
What protects people doing this work is rarely one dramatic change but a set of ordinary, structural things: caseloads that are realistic rather than aspirational, protected time set aside to reflect on difficult cases rather than squeezed between other tasks, clear channels for raising concerns without it counting against someone, and a working culture in which asking for support is treated as ordinary practice rather than as an admission of failure. Regular supervision, whether from a senior colleague or a trained peer, gives people a structured place to put down what they are carrying before it accumulates. So does simply working somewhere that takes the question seriously at a service level, rather than leaving it to be solved individually, case by case, by whoever is struggling.
None of this removes the difficulty of the work itself, which will always ask something real of the people who do it. But how sustainable that work is, over a career rather than a single hard week, depends heavily on the systems built around it: staffing, supervision, culture and the ordinary permission to say that something has been hard. Anyone finding the work harder to carry than usual is encouraged to raise it with a supervisor, manager or their own care team, in whichever direction feels right.