Recording steps, monitoring heart rate, and tracking sleep status, with the advancement of technology, smartwatches, smart bands, and other smart wearable devices are becoming the “first line of defense” for ordinary people in managing sleep. So, how reliable are smartwatches in monitoring sleep quality?
To accurately answer this question, we first need to understand the evaluation indicators of sleep quality.
First, let’s look at the integrity of sleep structure.If you wake up and deep sleep accounts for 18% to 25%, and rapid eye movement sleep accounts for about 20% to 25%, with fewer than 3 awakenings and each lasting less than 15 minutes, it can be considered that the sleep structure is relatively complete.
Second, look at sleep continuity. Healthy individuals should generally have a sleep latency of less than 30 minutes, and sleep efficiency should be greater than 85%.
Third, examine circadian rhythm characteristics. During sleep, body temperature generally drops by 0.5 to 1 degree Celsius, and melatonin peak concentration can reach five times that of daytime levels.
Fourth, assess the stability of physiological parameters. In a healthy sleep state, the respiratory rate should reach 12 to 20 breaths per minute, and blood oxygen saturation should be maintained above 95%.
Smartwatches primarily use green or infrared light to illuminate the skin, capturing minute fluctuations in blood flow to detect heart rate and blood oxygen levels, while also using a three-axis accelerometer to sense wrist movement, distinguishing between turning over and getting up, thereby constructing an individual’s sleep model.
Since smartwatches cannot directly monitor brain waves, their accuracy in sleep staging is significantly affected by individual differences. Currently, the average accuracy of mainstream smartwatches in sleep staging is between 75% to 85%. Therefore, overly focusing on the monitoring values of smartwatches may lead to sleep anxiety.
A sleep study published in The Lancet pointed out:“The best sleep monitoring device is your awareness of your own state.” A simple way to judge sleep quality is to look at daytime functioning; as long as your subjective perception of daytime functioning is not affected, your sleep is healthy. Therefore, there is no need to be anxious about the fluctuations in the values on monitoring devices.
If sleep is indeed poor, it can also be self-regulated through some scientific methods, including:
01Light Control Method
Exposure to nature and sunlight during the day, avoiding blue light from phone screens for 2 hours before bedtime.
02Temperature Intervention
Taking a hot bath before bed, with a temperature drop being key to aiding sleep, while keeping the room temperature at an ideal 18 to 22℃ .
03Sleep Environment
The curtain blackout rate should be above 95%; soundproofing or using white noise at 40 to 50 decibels to mask environmental noise.
04Exercise
Moderate-intensity exercise increases slow-wave sleep, and resistance training combined with aerobic exercise can enhance the effect.
05Diet
Eating protein at lunch to avoid drowsiness, and consuming carbohydrates at dinner to increase sleepiness, while avoiding coffee, smoking, and alcohol before bed.
If the above self-regulation methods are not effective, it is important to seek professional medical help in a timely manner for a sleep medicine evaluation and further intervention.
Source | First Affiliated Hospital of University of Science and Technology of China, Anhui Provincial Hospital
Editor | XU Qiuyang Editor | GU Pan
Organizers | Anhui Provincial Cyberspace Administration, Provincial Government Information Office
Platform Construction and Technical Support | Anhui New Media Group
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