Numbers to know, part 3

I’m asked a lot which metrics are the most pertinent to longevity, and how someone can really get a sense of where they stand health-wise. Here is a continued list from my last two posts (part 1 here and part 2 here) of 5 numbers I would consider important to know:

5. Sleep quality

This final point on the list was a lot tougher to generate, since I think there were several candidates for it that weren’t necessarily straightforward “numbers.” Sleep is critically important to virtually every component of our health. It certainly helps our brain by improving our memory and cognitive function, decreasing our dementia risk by clearing harmful proteins in the brain, demonstrating improvements in mood and avoiding psychiatric conditions, etc. Additionally, it has evident benefits for cardiovascular health, as one need look no further than the dramatic elevations in blood pressure and presence of major adverse cardiac events (i.e. heart attacks, strokes) in the population in the absence of quality sleep. Moreover, potentially its most profound effects are from strengthening the immune system, as clear associations exist between lack of sleep and several of the most common cancers (including colorectal, prostate, and breast), and a host of immune cell types are shown to have improved function with sleep. If that’s not enough, sleep even works at a molecular level within cells in the insulin signaling pathway to improve insulin sensitivity, a metabolic health principle at the very root of each major chronic disease.

Now that we’re sufficiently sold on the importance of good sleep, we assess it with four components: quantity, quality, consistency, and continuity. Quantity is of course how much we sleep (we want 8 hours of total sleep time), quality refers largely to the breakdown of staging and other metrics like heart rate variability (HRV), consistency is when we go to sleep and wake up each day (we want these times as consistent as possible, affecting sleep quality and overall circadian health), and continuity is how restful we are through the night, avoiding movement or wakeups.

This is all easiest to do if you have a sleep tracker device, which I cannot recommend highly enough. I have heard that there are other good devices out there, but still the most accurate and affordable appears to be the Oura Ring, which I have used extensively but have no affiliation with at this time. Oura will not only accurately record exactly when you are asleep vs. awake (remember, when you go to bed is not the same as when you fall asleep for counting “time asleep”), but it provides probably the best estimate of sleep staging among the wearable devices, which is critical to ensure you’re not selectively deficient in any kind of sleep. It also is the most accurate of the common sleep wearable devices for determining heart rate variability (HRV), which is an important metric for gauging recovery and readiness that most devices don’t even measure. Other related components like resting heart rate (RHR) and body temperature are included, and even movement or restlessness throughout the night. It will show all your raw numbers (which we recommend prioritizing for tracking purposes), but also present the data in easy-to-interpret summaries and scores, which can be helpful to gauge your progress or personal day-to-day changes.

As I mentioned, when it comes to devices, there are other options at either extreme. If you want to go crazy, I am dreaming (no pun intended) of trying Eight Sleep, which is essentially a mattress pad which can stage your sleep and change temperature to accommodate the stage of sleep you are in, facilitating higher quality for each particular window of time due to sleep’s significant regulation by temperature. This is incredible and seems to be practically an all-in-one sleep solution device, but it will cost you thousands of dollars. On the other hand, if you already have an Apple Watch, this can provide a basic assessment of sleep quantity and staging, although there are more question marks over its accuracy.

Honorable mention: DEXA scan

The DEXA scan is a body composition test that is starting to become much more common in the general population. Rather than going on about the specifics and alternatives, I’ll refer you to Nick’s recent post where he discusses the basics. Note, though, that we don’t just care about body fat percentage here (in fact, it might even be one of the less relevant numbers on there).  Among the numbers we care about most are appendicular lean mass index (ALMI, gauging how much metabolic reserve we have in the form of lean muscle), visceral fat (seeing how much fat we have over our organs, which contributes far more to inflammation and disease processes than subcutaneous fat), and bone mineral density (BMD, seeing how at risk we are for mechanical issues like osteopenia and osteoporosis).

Honorable mention: comprehensive cancer screening

Most of the time, cancer screening is not as much a number as it is a binary yes/no, but I mention it because it has to be among the tests where we are most aggressive. Of the major chronic diseases, cancer is perhaps the one where we have the least tools for prevention, and therefore our best strategy is to be proactive, early, and frequent with screening. Current guidelines are far too conservative for starting ages and regularity of surveillance; stay tuned for future posts on our thoughts for timing and frequency, but also ask your doctor as soon as possible about staying ahead on these tests (namely for colorectal, breast, cervical, lung, and prostate cancer).

Subscribe to our monthly newsletter

Support our community projects

DISCLAIMER:

All content and information provided on or through this website is for general informational purposes only and does not constitute a professional service of any kind. This includes, but is not limited to, the practice of medicine, nursing, or other professional healthcare services. The use of any information contained on or accessed through this website is at the user’s own risk. The material on this site or accessible through this site is not intended to be a substitute for any form of professional advice. Always seek the advice of a qualified professional before making any health-related decisions or taking any health-related actions. Users should not disregard or delay in obtaining medical advice for any medical condition they have, and should seek the assistance of their healthcare professionals for any such conditions.