Why that time matters
Dr. Berg later focused specifically on 2 a.m., explaining how the body’s circadian rhythm is meant to work. Normally, cortisol is lowest around 2 a.m. and peaks around 8 a.m. In his case, the cycle was reversed—he felt alert at night and exhausted in the morning.
Long-term sleep deprivation, he noted, has been linked to serious conditions including heart disease, dementia, and diabetes.
Ways to lower cortisol at night
Dr. Berg says there are strategies that may help reduce cortisol levels while sleeping and prevent those early-morning awakenings. One of the most important, he says, is magnesium.
A lack of magnesium can cause muscle tightness, cramps, and heightened cortisol. He explained that stiffness in the back or leg cramps—especially when pointing the toes—can be signs of deficiency.
Magnesium also supports muscle relaxation, calms the nervous system, and can help reduce anxiety and irritability. Dr. Berg recommends taking magnesium supplements in the evening before bed.
He added that magnesium levels in the body are typically lowest around 6 a.m., which may help explain why certain medical issues—such as heart attacks, strokes, and restless leg syndrome—often occur in the early morning hours.
