Are your hormones in tune? Mounting evidence suggests that exposure to light at night -- whether you're asleep or awake -- might play a crucial role in cancer, diabetes, and obesity. The World Health Organization classified "circadian disruption" as probably carcinogenic, and light at night is considered by some to be an endocrine disruptor that may affect melatonin, cortisol, ghrelin, leptin, and testosterone. "Most people think, and the drug companies want you to think, that waking up at night is bad for you," says Richard Stevens, ., a cancer epidemiologist at the University of Connecticut health center. But that's not the case, he says -- it's exposure to light at night that's the problem. "If you wake up at night, as most of us do, that is a period of quiet wakefulness -- stay in bed, in the dark, and enjoy it," Stevens suggests.
When measuring testosterone levels, it is critical to determine the levels of both free and total testosterone to understand the cause of any observed symptoms of deficiency (Khosla et al 2008).
Because of difficulties with equipment standardization and inter-laboratory variability, it is recommended that physicians consistently use the same local laboratories and gain familiarity with the accuracy, precision and definition of normal values for the assays offered in their communities (Morales et al 2010).