Sleep Score Interpretations (1/n)

A new ongoing series...

We’re going to have an ongoing series on this blog where one of us (or a guest) shares their sleep data from a tracking device along with notes of their behavior/activities that day, which might include things like what they ate, did they exercise, and did they drink any caffeine or alcohol. We’ll then briefly do our best at playing Sherlock Holmes to connect the dots between the day’s behaviors and the sleep tracker’s data.

We might also throw in some posts that look at data changes over longer periods of time when a major lifestyle change has been made. For example, going on a hardcore ketogenic diet, eliminating caffeine or increasing cardio workout frequency.

The three of us wear sleep trackers religiously and it has been a truly red-pill experience (the one that Neo took, thereby transporting him into the real world). For example, we’ve noticed that for each of us even drinking one glass of wine just before bed has a negative impact on our sleep. Two glasses nukes our sleep quality completely.

Ben has noticed that if he eats a large meal it needs to be 4 hours or more before bed otherwise he experiences a significant decrease in sleep quality. For Laura the figure is 3 hours.

You’ve probably heard that you shouldn’t drink caffeine in the afternoon, but what if we told you that even drinking to much caffeine at 9am could make you toss and turn more at night (something a sleep tracker will pick up)? Tossing and turning lowers the amount of deep and REM sleep you get.

The main takeaway is this. There is enormous value to be harvested for every single person by understanding their own unique physiological reactions to their lifestyle, daily activities and food/drink intake. What has a negative impact on one person’s sleep (certain foods, proximity of eating to bed, etc) might not negatively impact someone else. The only way to find out about your own biology is to start tracking it.

While all people are unique, to borrow an idea from Mark Twain - our experiences rhyme. That’s where the big value is going to be in these posts. You won’t be just like us, but you can use the experiences we post here as a starting point to begin ferreting out possible connections between activities, lifestyle and sleep quality.

With that introduction out of the way we’re going to explain category by category what data sleep trackers are capturing and why it’s relevant. This post will be linked at the top of all future sleep score interpretation posts for reference. In future posts we’ll work on the assumption that everyone knows what HRV and RHR mean and whether it’s best if they are low or high - for example. If you forget what anything means you can always click the link and check back here for the overview.

Most of the text below is pulled directly from the Oura Ring app - which is the primary sleep tracking device the three of us use.

Time in bed. Practically speaking Time in bed means the amount of time you are horizontal. If I am in bed and reading sitting up the Oura ring is smart enough to detect that and won’t count that time. That said, the Oura is not smart enough to know if I am listening to a book on tape laying down and mostly still. It also sometimes gets confused even if I am laying down on my belly and reading a book so long as I’m very still.

Total sleep. This one is self explanatory. Oura knows when you are actually sleeping by observing your movement and pulse data.

Sleep efficiency. Sleep efficiency reflects the percentage of time spent asleep compared to time spent awake while in bed. For adults, sleep efficiency of 85% is a sign of peaceful and uninterrupted sleep. It’s common for sleep efficiency to slightly decrease with age.

Resting heart rate (RHR). RHR is a good measure of your recovery. It’s the number of times your heart beats per minute when you’re at rest. Normal resting heart rate for adults can range from 40-100 bpm. Intense training, a late meal, elevated body temperature, or even thoughts and emotions, such as stress or excitement, can keep your heart rate up during your sleep.

Restfulness. Restfulness tracks your wake-ups, excessive movement, and getting up from bed during your sleep. It takes into account all your sleep, including naps. Everyone moves and wakes up during sleep, but too much tossing and turning can have an effect on your sleep quality. Restless sleep is less restorative than uninterrupted sleep, and it’s usually the cause of daytime sleepiness. Disturbances can be caused by things like stress, noise, bed partners, pets or different foods.

REM. Associated with dreaming, memory consolidation, and creativity, REM (rapid eye movement) sleep plays an important role in re-energizing your mind and body. REM sleep includes all your sleep, including naps. REM sleep makes up anywhere between 5-50% of your total sleep time. On average, the optimal amount for healthy adults starts from 1.5 hours, but slightly decreases with age. REM is regulated by circadian rhythms, in other words your body clock. Typically you get more REM sleep during the later half of the night. Getting a full night’s sleep, sticking to a regular sleep schedule and avoid caffeine, alcohol or other stimulants in the evening can increase your chances of getting more REM.

Deep Sleep. Deep sleep is the most restorative and rejuvenating sleep stage. Deep sleep makes up anywhere from 0-35% of your total sleep. On average adults spend 15-20% (1-1.5h) of their total sleep time in deep sleep, the percentage usually decreasing with age. When you’re in deep sleep, your blood pressure drops, heart rate and breathing rates are steady, arm and leg muscles are relaxed, and it’s harder for you to wake up. During deep sleep your muscles grow and repair, immune system is refreshed, and brain flushes out toxins. Usually, you get more deep sleep during the early night. If you want to get more deep sleep, try to keep your sleep schedule consistent and avoid heavy meals, stimulants and bright screens 1-2 hours before bed. Long naps and caffeine in the late afternoon and evening can decrease the amount of deep sleep, whereas exercising regularly can increase it.

Latency. Sleep latency is the amount of time it takes you to fall asleep at night. Sleep latency is only shown for your longest sleep period. Ideally, you should fall asleep within 15 to 20 minutes of lying down. Falling asleep in less than 5 minutes can be a sign of overtiredness. If you have trouble falling asleep, try doing something relaxing, ideally in low light, until you feel sleepy again. For some, it can help to get out of bed, but avoid doing something that energizes you.

Timing. Sleep timing plays an important role in your sleep quality and daytime performance. Ideally your sleep should be aligned with nature’s 24-hour rhythm. Optimally, the midpoint of your night’s sleep should fall between midnight and 3AM, but there can be some variation between morning and evening types of people. If you feel tired during the day, the best time to take a nap is usually early afternoon.

Oxygen Saturation. This is your average blood oxygen level during the night. Stuffy nose, sleeping environment, some underlying conditions like allergy and your overall health may lower blood oxygen levels. Having a blood oxygen level between 95-100% is considered normal.

Breathing Regularity. I’m posting their explanation with graphic below:

Breathing regularity matters because it can tell you whether something is disturbing your breathing, like sleep apnea. Breathing disturbances can cause cascading effects, ruining all aspects of sleep quality.

Already explained resting heart rate, just posting this graph for later reference.

HRV - Heart Rate Variability. HRV reveals how your body responds to training, traveling or stress. HRV is personal, and it’s affected by various factors such as age, health status, and fitness level. Average HRV can vary from anywhere below 20 to over 120. High HRV is associated with rest-and-digest, general fitness, and good recovery. Low HRV is associated with fight-or-flight, stress, illness, or overtraining.

Body Temperature. Body temperature variations can reveal a lot about your recovery and overall health. It’s normal for body temperature to rise after eating, drinking or exercising late, or when sleeping in a warm environment. A sudden rise can also indicate that you’re coming down with something. When this happens, it’s a good idea to take your temperature with a thermometer, and allow yourself to rest. If you track your menstrual cycle, you may spot monthly patterns in your body temperature Trend view. It’s common for body temperature to fall during the first half of the menstrual cycle, and rise slightly during the second half. Oura measures your body temperature while you sleep and shows your average temperature relative to your baseline.

Your respiratory rate is the average number of breaths you take per minute. It is a good indicator of your health status. The typical respiratory rate for a healthy adult at rest is 12-20 breaths per minute. Because breathing is highly individual, it’s best to compare your numbers to your own baseline.

That’s it - the comprehensive overview of each data point we’ll be referring to in future posts. Tata for now!