If you suffer from nightmares, night terrors or sleepwalking, you are most likely experiencing a disruption to your slow wave sleep cycle.

More broadly, though, not having enough slow wave sleep is about not getting enough deep rest, which will have serious impacts on your body. “Sleep is an evolutionary necessity,” Jacobson says, “We can go without food and water for certain periods of time, but if we go with extended amounts of sleep deprivation usually there is some significant effect.”

You might notice your immune system slowing down or a breakdown physiologically in how your body heals and repairs. You might notice problems with processing emotions and memories. You might see hormonal issues. You might even see mental illness, given that there has been significant research linking a lack of sleep with a rise in anxiety (weighted blankets could help), depressive episodes and other problems with your mental health.

Sleep is absolutely crucial to our bodies and our minds, and slow wave sleep is an important part of that process.

Slow wave sleep: what is it, and why is it so important for your mental health?