Sleep deprivation is a multi-factorial health issue that may trigger a cascade of serious medical conditions. More on this in a little bit, but nonetheless, it has a significant impact on the body, including the autonomic nervous system (ANS) that regulates many of the automatic processes — heart rate and blood pressure. The connection between sleep deprivation and HRV is relevant in connection to the activity of the ANS, as HRV has been found to be a reliable indicator of ANS function and overall health.
HRV and the autonomic nervous system
Studies have shown that sleep deprivation can cause a reduction in HRV, particularly in the high-frequency range, which is primarily influenced by the parasympathetic nervous system. The parasympathetic nervous system, or PNS, is responsible for calming the body, reducing stress, and maintaining balance and homeostasis. It is particularly active during times of rest and sleep.
When you are asleep, there is a shift in ANS activity from sympathetic dominance (fight-or-flight response) to parasympathetic dominance (rest-and-digest response), which helps the body relax and prepare for restorative sleep. However, when you are sleep deprived, this natural shift in ANS activity is disrupted, leading to reduced HRV.
When it comes to dissecting HRV, we look at high-frequency and low-frequency HRV which each have their own relationship with the autonomic nervous system.
Sleep deprivation and low/high-frequency HRV
The reduction in high-frequency HRV during sleep deprivation is thought to be due to an increase in sympathetic nervous system activity, which is responsible for the body’s fight-or-flight response. This increased sympathetic activity during sleep deprivation can lead to a state of hyperarousal, making it difficult to fall asleep and stay asleep, perpetuating the cycle of sleep deprivation.
Additionally, sleep deprivation has been associated with an increase in low-frequency HRV, which is influenced by both the sympathetic and parasympathetic nervous systems. This increase in low-frequency HRV may reflect an increase in sympathetic nervous system activity when you’re sleep deprived, which can lead to increased stress and anxiety, and negatively impact your overall health.
Reduced HRV is associated with an increased risk of cardiovascular disease, metabolic disorders (i.e obesity), and poor mental health outcomes, including depression and anxiety. Chronic sleep deprivation has been linked to an increased risk of these health conditions, highlighting the importance of getting enough quality sleep.
In conclusion, sleep deprivation can significantly impact HRV, leading to a reduction in high-frequency HRV and an increase in low-frequency HRV, which can negatively affect overall health and well-being. Therefore, it is essential to prioritize healthy sleep habits to maintain optimal HRV and overall health.
Whether you want to monitor your own health or you’re working with patients, measuring HRV nocturnally may serve as an essential tool to help to quantify how certain levels of sleep deprivation may affect HRV and overall recovery.