Depth of sleep

# What is sleep depth? Sleep depth refers to the extent to which sleep is restorative and regenerative. It is an essential component of sleep and varies in the different sleep phases. The sleep cycle consists of several phases, which can be divided into two main categories: Non-Rapid Eye Movement (NREM) sleep and Rapid Eye Movement (REM) sleep. The deepest depth of sleep is reached in non-REM sleep, particularly in stages 3 and 4, which are often referred to as "deep sleep". # Sleep cycle During deep sleep, the body is most relaxed, heartbeat and breathing are reduced to a minimum and brain activity shows characteristic slow waves, the so-called delta waves. This phase is crucial for physical recovery, cell repair and the immune system. Memory consolidation, in which experiences and information are transferred from short-term memory to long-term memory, is also supported by the deep sleep phase. A lack of deep sleep can lead to tiredness, reduced cognitive performance and increased susceptibility to illness. The depth of sleep is therefore an essential feature of sleep that determines the quality and recovery of sleep. During a normal sleep cycle, the body goes through several stages, ranging from light sleep (non-REM stages 1 and 2) to deep sleep (non-REM stage 3) and REM sleep. In the deep sleep phase, important processes such as muscle growth and the release of growth hormones are supported. The immune system is strengthened and the brain consolidates memories and learns. > ## Good to know > > Some people naturally have deeper sleep phases than others due to genetic variants, which can lead to better recovery and higher cognitive abilities, even if the total sleep duration is shorter. # Factors of sleep depth Various factors can influence sleep depth, including age, stress, environmental conditions (e.g. noise and temperature), physical activity and genetic predisposition. While sleep depth naturally decreases with age, there are methods and lifestyle habits that can contribute to restful and deep sleep. People who sleep deeply enough tend to wake up refreshed and rested, while those who sleep too little often suffer the consequences. # What do genetics have to do with it? Sleep depth is not only influenced by external factors such as stress, diet and environment, but also by genetic factors. Research has shown that certain genes and their variants, known as single nucleotide polymorphisms (SNPs), play an important role in the regulation of sleep depth. These genetic variations can influence how deeply a person sleeps, how long they stay in the different sleep stages and how restorative their sleep is. The SNP rs679711 is located in a non-coding region of the WNCG gene, which is classified as "within non-coding gene". Although this SNP is not directly located in coding regions, it may affect regulatory elements or genes involved in the control of sleep processes. Variants of this SNP may affect the expression of neighboring genes involved in the regulation of sleep architecture and sleep depth. Differences in the alleles of this SNP could lead to different sleep depths by affecting regulatory networks that modulate neuronal activity and sleep quality. The TLN2 (Talin 2) gene plays a role in cell adhesion and signaling in cells. Variants of this SNP can influence neuronal activity and thus the regulation of sleep architecture. Research suggests that certain alleles of this SNP may be associated with altered sleep depth, meaning that people with this genetic variation may experience deeper or less deep sleep stages, affecting their sleep quality. The SNP rs73598374 in the ADA gene (adenosine deaminase) is associated with sleep depth. The ADA gene codes for the enzyme adenosine deaminase, which plays a key role in the degradation of adenosine, a neurotransmitter that regulates the sleep-wake cycle. Variants of this SNP can alter the activity of the enzyme ADA, which in turn affects the concentration of adenosine in the brain. These changes can modulate sleep depth, as adenosine plays an important role in regulating sleep pressure and sleep depth. Individuals with certain alleles of rs73598374 could therefore have a different depth of sleep, which could affect the quality of their rest.