If the idea is to avoid the effort of exercise, perhaps it would be worth considering the possibility that the effort itself is essential.
- Impact and stress strengthening the muscles, bones and tendons / ligaments
- energy use that leads to better sleep
- increased blood flow, development of new capillaries, stretching of blood vessels
- if you exercise outside, exposure to sunlight
- the release of all the associated neurochemicals
I have a suspicion that anything designed to mimic exercise would hurt as much as the actual thing given that so many of the benefits of exercise involve damaging bone and tissue then repairing it
My point is that, even though we might find even more ways to improve/modify our bodies, they will come with slew of risks that are just not worth it if you can achieve it naturally.
On another note, I feel like there is severe muscle inflation in media which would distort how fit a person should be. You really do not need to kill yourself in the gym or hop on a some reddit-approved juices to get very fit. Just gotta experiment and find a comfortable full body workout that you can do consistently, like you brush your teeth every day.
That's part of why steroids were and sometimes still are used medically for people with cancer and other wasting diseases. It makes them eat more (they're usually strongly appetite inducing) but they also just help develop muscles even if sedentary.
(Of course it would be far more effective to also engage in high intensity resistance training.)
Cortico steroids usually result in muscle mass loss.
...The men in the testosterone groups had significant increases in the cross-sectional areas of the triceps and the quadriceps (Table 4); the group assigned to testosterone without exercise had a significantly greater increase in the cross-sectional area of the quadriceps than the placebo-alone group
[0] https://www.nejm.org/doi/full/10.1056/NEJM199607043350101> When I asked Ashley if it was possible to design a drug that mimicked the observed effects of exercise, he was emphatic that, no, this was not possible.
https://diabetesjournals.org/diabetes/article/72/Supplement_...
Even lactate, formerly regarded as simply a waste product, is one.
But sure, a cocktail may be possible at some point, beyond getting a blood transfusion from someone fitter and maybe younger.
Exercise for him is (a) expensive and (b) really really really painful.
If he could take a pill that simulated this it would be amazing for his life.
After a few experiments that felt more like drowning than swimming I finally got the hang of it. But it left me seriously worried about exercise in my future. After all, joint problems are likely going to happen again in my future. And I started to wonder: how do disabled folks do this? It must be incredibly difficult (and expensive!). I really am incredibly lucky across multiple fronts to have the life that I have.
It is really all about working with what capabilities you still have, and maximizing those. Even that may provide enough healing & fitness to get back to a bit of previously constrained activities.