Stable plasma ghrelin levels was shown in 11 studies using either short [25,132,133,134] or long-term [26,137,138,139,140,141] or very long-term [153] aerobic training [25,26,132,133,134,137,139,140], resistance [141], or combined training [138,153] in active [133], inactive [140], trained [132,134], healthy overweight/obese [25,137,139,141,153], and clinical obese with type 2 diabetes mellitus [148] or osteoarthritis [26]. The gene discussed is GHRL; the disease is type 2 diabetes mellitus.