INS and myalgic encephalomeyelitis/chronic fatigue syndrome: Chronic elevated levels of insulin and proinflammatory cytokines could explain the negative regulation of cortisol secretion, where increased insulin causes a deficient cortisol response to hypoglycemia, as occurs in patients with ME/CFS assessed using the insulin-induced hypoglycemia test [54, 58, 253, 262, 263, 365].