Blood Sugar: The Most Important Data Point You Can Measure For Your Health

A couple times a year I spend a week or more waking up each morning, stabbing my finger with a needle and dropping some blood onto a stick.

Sounds fun right?

Well at least more fun than my morning cold shower 🥶.

Why make myself bleed each morning?

To measure my blood sugar and make sure it is optimal. Having optimal blood sugar is one of the most important data points you can measure for your own health.

Chronically elevated blood sugar has been tied to many diseases, from heart disease[1], cancer, and alzheimers. It is no wonder when we look at all cause mortality, AKA dying of anything, the higher your fasting blood sugar the greater your chance of dying[2]. Unfortunately due to the increased presence of processed foods high in carbohydrates and the lack of physical activity in today’s modern world, a majority of people have higher than normal blood sugar[3].

Before we look at how to determine your blood sugar level let’s talk about what your blood sugar should be.

One of the best ways to determine how well you are managing your blood sugar is to look at what is called your fasting blood sugar level. All this means is you measure your blood sugar after not eating or drinking anything except for water for 12 hours. For example, if you finish eating at 6 PM you would only drink water until 6 AM or after the next day at which point you would perform the blood sugar measurement.

Your blood sugar is commonly measured by your doctor when they send you to get blood work done. If you look at the report from your doctor or the lab itself it might be called fasting glucose. Luckily you do not need to go get blood drawn in order to measure your blood sugar, you can measure it at home by yourself with a simple blood sugar meter.

Once you have your own meter, I would suggest measuring your blood sugar first thing in the morning after a 12 hour fast for 7 days in a row. This will give you a nice average of what your fasting blood sugar looks like. You will likely see changes day to day, but a 7 day average will give you a good idea of what it looks like on average.

The question then becomes what optimal fasting blood sugar should be?

According to the CDC[4]

“A fasting blood sugar level of 99 mg/dL or lower is normal, 100 to 125 mg/dL indicates you have prediabetes, and 126 mg/dL or higher indicates you have diabetes.”

We also have research that shows what the average blood sugar is by age[5].

Looking at this data, it looks like blood sugar goes up with age.

Again we have to ask ourselves, is that a good thing?

If we take the CDCs guideline of being below 99 mg/dl, men look pretty good up until age 50, women look pretty good well into the 70s and 80s. That is not bad right?

The interesting thing comes when we look at fasting blood sugar and it association with all cause mortality[6].

The Y-axis of the above graph shows us the hazard ratio of dieing of all causes. Anything above 1 indicates an increased risk of dying. On the X-axis we have fasting blood sugar. If we look at what blood sugar level intersects with a hazard ratio of 1 we see it’s between 80-90 mg/dl regardless of your age.

Remember the CDC said anything below 99 mg/dl is “normal”.

Unfortunately the normal person is not healthy[7], so you likely want to be better than normal when it comes to blood sugar.

Now if you are reading this and thinking there is no way your blood sugar is too high because you workout on the regular or are an athlete, you might want to think again.

In one study that looked at the blood sugar of 10 sub-elite athletes, 4 out of 10 of the athletes spent 70% of the time above 106 mg/dl. You might be thinking, that is not that bad considering they may have been eating meals with carbohydrates in them. True, except that does not include the 2hrs after their meals! Three out of ten athletes had a fasting blood glucose level in the pre-diabetes range, 100-125 mg/dl! Only 3 athletes had a fasting blood sugar below 90 mg/dl! Only one athlete spent significant time at around 70 mg/dl and that was primarily because they did not eat as much[8].

Below is the data from the study. The column labeled FBG is their fasting blood sugar in mmol/L. I have translated those numbers to mg/dl which is what is commonly used in the US and is in red color. Also pay attention to the column PBF which is their body fat percentage. These athletes were not overweight either!

Based on the research around fasting blood sugar, it appears that a fasting blood sugar between 80-90 mg/dl is an optimal range for pretty much everyone. We also know that just because you are a lean active individual that it doesn’t mean that your blood sugar is automatically within this healthy range.

If you want to determine your own fasting blood sugar, you can easily purchase your own blood sugar meter and test at home. Perform the test in the morning after not eating for 12 hours for 7 days in a row and calculate your average fasting blood sugar. If you land between 80-90 mg/dl you are doing great.

If you fall above 90 or below 80 you will want to start to look into why. There can be a number of reasons why your blood sugar may be above or below the optimal range including, sleep, stress, diet, gut health, and many more reasons. Basically any environmental mismatch can cause your blood sugar to be outside the optimal range. If you need help addressing some of these lifestyle factors you can get a ton of free information by joining my newsletter, just enter your email below.

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  1. (n.d.). Glucose Control and Cardiovascular Disease – NCBI – NIH. Retrieved November 24, 2020, from
  2. (2017, August 15). Association between fasting glucose and all … – NCBI – NIH. Retrieved November 24, 2020, from
  3. (2018, November 28). Only 12 percent of American adults are metabolically healthy …. Retrieved November 24, 2020, from
  4. (n.d.). Diabetes Tests | CDC. Retrieved November 27, 2020, from
  5. (2017, August 15). Association between fasting glucose and all … – NCBI – NIH. Retrieved November 29, 2020, from
  6. (2017, August 15). Association between fasting glucose and all … – NCBI – NIH. Retrieved November 29, 2020, from
  7. (2018, November 28). Only 12 percent of American adults are metabolically healthy …. Retrieved November 27, 2020, from
  8. (2016, June 14). Blood Glucose Levels of Subelite Athletes During … – NCBI – NIH. Retrieved November 24, 2020, from

2 thoughts on “Blood Sugar: The Most Important Data Point You Can Measure For Your Health

  1. Jennifer Corbet April 8, 2021 — 6:20 pm

    Good info. Thank you. I am curious what you have to say about post-exercise fasting blood sugars. Without exercise, I am within the ranges you specify. Post-exercise, however, I am much higher (sometimes as high as 135, then it drops later). Thoughts?

    1. Hi Jennifer, thanks!

      Exercise will cause the release of glucose into the blood stream to fuel your movement, especially when the exercise is intense. Therefore if you test your glucose post exercise, even in a fasted state, you can see a rise in blood sugar. So what you are seeing is not uncommon at all and nothing to be alarmed about.

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