Strange, you did not need proof from Tight-and juicy, so I dont think that it is proof that you need.
All of the mentioned excercises are backed by science. Do I have to search for you to believe it?
Furthermore:
The placebo effect is a scientific concept. And faith is meant in this context. You basically programm your unconsciousness to become calmer.
I dont exactly know what you want to know, because if you google secular meditation you find mainly Buddhist meditations and that is what you do not want. But those are the meditation that are backed by science.
I think it's quite simply that I could tell that
@Tight_N_Juicy 's advice came from what works for her personally, and it's very much non-spiritual and secular (and that's what I asked for). Some of it could apply to me very well (secular angle, finding your centre, nature and ritual focus), some of it occasionally well and occasionally not so well (cannabis, I'm an on off user with a recent few months on due to bereavement and just entering an indefinite break for some extra mental clarity), and other parts just don't apply to me personally (I don't think I could personally enter a deep sense of relaxation with very loud music). So essentially, I can take some tips from her personal methods. I feel that you, on the other hand, are still pushing the spiritual side of meditation, which I've been clear in stating that I'm not interested in it because I find it very off putting.
I think believing that meditation can work for you personally does play a role, but then again, it's well known that deep breathing exercises alleviate stress. One other method I could use is in activating the mammalian dive reflex by simply sticking my head underwater, which gives the same results as meditation and mindfulness (slower heart rate, deeper breathing due to holding your breath and it blocks out a lot of noise making it very peaceful). It's just you can only do that for half a minute or so at a time, and It's hardly very practical. I think the links between a state of deep relaxation and the mammalian dive reflex are more strongly linked than the placebo effect.
Science backs up all forms of deep relaxation (including Buddhist meditation and the mammalian dive reflex), not just Buddhist meditation, which I've been quite explicit in not being interested in. The reason why is (frankly and absolutely no offence meant to anyone who is Buddhist, you do you) I think Buddhism is bollocks. I don't believe in reincarnation, achieving "enlightenment", spirituality and I don't think its focus on linking desire with suffering is healthy at all.
To provide an analogy, it sounds like you're giving advice to a vegan who's trying to increase their protein intake for better exercise performance and muscle mass building and looking for tips on how to do that in a plant based diet, by constantly repeating "why don't you just have a steak and cheese sandwich?"