Three nights, only three nights of bad sleep is enough to reduce the body’s ability to process glucose and this will increase the risk of diabetes, the researchers discovered. The impact of suppressing deep sleep for three nights on young adult is similar to as if they have gained 8 kg to 13 kg.

Deep sleep is the best form of sleep to restore mental clarity. A test was conducted on nine young volunteers who spend five nights sleeping in a laboratory. On the first two nights, they slept undisturbed. The next three nights, speakers near the bed will emit low-level sound whenever their brain patterns indicate they are going into deep sleep. The sound emitted will not wake them up but will drift them back from deep sleep to lighter sleep. After the test, these volunteer showed insulin sensitivity decreased by 25%. Meaning, they will need more insulin to process the same level of glucose.