What is it?
Sleep duration is simply the amount of time an individual is asleep. This measure is essential to quantify, as it directly impacts physiological and psychological parameters in the short and long term, impacting health, performance, and longevity.
What does it measure?
Sleep duration is the total sum of time spent asleep, regardless of sleep stage. Using combinations of heart rate, heart rate variability, breathing, motion, and pulse waveform data, approximating sleep versus awake time is possible.
Biostrap uses inputs from all the listed measurements to estimate light sleep, deep sleep, and time spent awake; therefore, the reflected sleep duration is the sum of light and deep sleep.
Correlation with health conditions
Total sleep duration is a commonly reported metric and highly correlates with health outcomes. Sleep is vital to regulating biological processes, allowing adaptation, recovery, and preparation. Many repair processes occur during sleep, with surges in growth hormones and reduction in stress hormones.
Physiologically, increased sleep duration has been shown to reduce stress, improve cardiovascular markers (e.g. heart rate, heart rate variability, and arterial stiffness), reduce weight gain, improve immune function, and lower risk of all cause mortality and varying diseases. As such, sleep appears to improve physiological pathways robustly.
In addition to physiological effects, increased sleep has many cognitive benefits, including improved memory, problem-solving, and reaction speed.
Normal or acceptable range
The American Academy of Sleep Medicine recommends at least 7 hours of sleep per night for adults aged 18-60 years. The National Sleep Foundation recommends supplementing this recommendation with 7-9 hours of sleep per night for adults aged 65 years and older.
Biostrap records users’ sleep each night, and from this data, we can gather average values of distinct populations.
Interpreting Trends
Considering the broad health implications associated with sleep duration, tracking sleep duration over time is recommended, so individuals may notice trends in their behavior. Including sleep duration into longitudinal metrics can either explain or rule out other physiological trends and therefore is included in Biostrap biometrics, allowing users and remote monitors to have a broader view of individual health.