Joyce McClendon Evans was born in 1937 in Mayfield, Kentucky. She met her husband Joel when they took the same Sophomore Chemistry class at Mayfield High. They would be married in 1956. They moved to Murry in 1967, where Joyce would work on her degree in Physiology and biophysics. Joyce realized she was in over her head with family, home, school, and political activities; for the time being, continuing education got scuttled. By 1968, Joyce shifted from being a teaching assistant in Physics to conducting research at Wenner-Gren Laboratory at the ImU.K. The excitement of cutting-edge experiments and their results pulled her deeper into a lifelong commitment. In the 1980s and 90s, research at Wenner Gren changed direction to include researching cardiovascular changes occurring during and after zero gravity and increased gravitation, such as in high-performance aircraft.

Joyce has advocated that more studies are needed that include both genders since women's and men's physiological differences produce differing results. In particular, there needs to be evidence that the current favorite countermeasure to weightlessness-induced deconditioning, a centrifuge in space, will be nearly as effective in women as in men. Joyce retired from the U.K. in 2019 but continues to research preparing aviators and astronauts in countermeasures to reduce G-LOC (G-induced Loss Of Consciousness) and reduce the cardiovascular deconditioning of weightlessness.