Can walking up and days hills maybe around 2 miles the morning of blood work cause my creatinine levels to rise and my gfr to lower? The day of my blood work I went hunting from around 6am till around 1130 am drunk maybe 10-16oz of water it was a fast blood test so hadn't ate since around 7pm the night before. Got finished hunting went to get my blood drawn around 1230 and my creatinine level had rose from 1.00 to 1.4 my BUN went from 12 to 14 and my gfr went from 87 to 59 I'm just wondering if what I had done that morning and the days leading up to my blood work affected my results. I had also started riding bike a couple days before with my daughter in the evenings. Thanks