@rrr1952
Hi, For me strenuous exercise/ work drops my GFR, fortunately it does rebound. I have a bad habit of working until I drop, literally, the thought of stopping before completion isn't how I work. The habit of a lifetime is hard to stop.
I try to keep to the same pattern when having blood drawn at around the same time of day, this gives me a more stable record of how my kidneys are doing. By watching my test results I know what I can get away with and what I can't. Some medications can rob me of kidney function quickly and I stop them when this happens. Gabapentin is one of the worst. I don't let anything or anyone mitigate my kidney health, including my Dr's anymore.
For me painkillers rob me of kidney function so if absolutely required I will use opioid based pain relief only, it happens very rearly having a high tolerance of pain. Stay away from dark coloured sodas as the chemical colouring taxes the kidenys.
I reduced the amount of red meat to one small meal per week, cut the amount of salt I was using to minimal and don't do anything stupid, mostly! I watch the colour of my urine to tell me if I'm hydrating enough or not, works well for me.
Thirteen years ago I started with zero kidney function, managed to push it up to GFR 63 with extreme dietry and lifestyle changes. I'm 73 now and have relented to a more suitable diet and lifestyle, kidney function is down to GFR 42 and reasonable stable. I have enough function to see me out and am more concerned with other health issues that have come along to test me.
Cheers