Slow wave sleep, also known as normal phase sleep or slow eye movement sleep, refers to the third and fourth sleep stages. Slow wave sleep can be divided into four stages from shallow to deep. The first and second stages are shallow sleep, and the third and fourth stages are deep sleep. Deep sleep period is of great value to the recovery of spirit and physical strength. In the whole slow wave sleep, parasympathetic nerve activity is dominant, which can cause heart rate to slow down, blood pressure to reduce, gastrointestinal activity to increase, muscle relaxation in the whole body.
Generally, about 20% of healthy adults sleep in slow wave sleep every night. If you sleep for 8 hours at night, the slow wave sleep time is more than 90 minutes. However, deep sleep is affected by many factors, such as age, physical activity and so on. So there is no uniform standard for how long deep sleep takes.
Especially at the end of high-intensity training, runners need more high-quality sleep to promote physical recovery. If the sleep quality is high enough, the next day you can continue to carry out low-intensity training, otherwise you need to let the body continue to rest.