Research Outline

Glucose Levels Variability


To understand normal glucose fluctuations during the day and night as well as how physical activity and type of food ingested influence glucose blood levels.

Early Findings

  • Blood sugar or glycemic levels have a normal range from 82 mg/dl to 110 mg/dl, although medical guidelines establish that fasting glycemia should not exceed 100 mg/dl.
  • These levels change after a full meal. In healthy subjects, postprandial (post-meal) glycemic levels should be lower than 140 mg/dl. Higher finds could be an indicator of diabetes or insulin resistance, also known as prediabetes.
  • When it comes to food type, the glycemic index is a useful tool to determine how a specific meal will impact glycemic levels. Foods with low glycemic index lead to a slow release of glucose in the blood while foods with a high glycemic index do so rapidly.
  • Tables have been compiled to include the glycemic index of over a 1,000 different food items, which were published on this 2008 article.
  • Data from continuous glucose monitoring (CGM) has allowed for accurate graphs to be created. It has been reported that diets with high carbohydrate and high glycemic load lead to a greater variability in glycemia levels. Meanwhile, diets with higher fat levels and low carbohydrate show lower variability.
  • Studies have suggested that while glucose levels are highly dependent on food intake, insulin levels are dependent on both food intake and the circadian rhythm.
  • The circadian rhythm is the internal biological clock, which is highly influenced by daylight. It has been seen that insulin levels are lower towards the end of the day, which leads to higher glycemia after dinner than glycemia levels seen after breakfast.
  • Furthermore, it has been reported that people who work during the night -which leads to a misalignment of the circadian rhythm- have lower glucose tolerance. This means that they regularly have higher glycemia levels, predisposing them to suffer type 2 diabetes mellitus.
  • Glycemia levels decrease after exercise, and it has been reported that a constant workout routine improves insulin sensitivity, which would be one of the mechanisms through which glycemia levels go down.
  • The sensitizing effects of exercise when it comes to insulin usually last for approximately 24 hours. In some people, there can be a spike in blood sugar right after exercise, as hormones such as glucagon -which promotes glucose release in the blood- are secreted.

Summary of Findings

  • During this initial hour of research, we were able to provide information about the expected blood sugar levels in healthy subjects as well as how these levels change after a meal or a workout. We have also provided information obtained through continuous glucose monitoring, which is an upcoming trend in glycemic management.
  • In addition, we have identified how different types of meals can influence glucose levels, which could depend on the glycemic index of the food consumed but also on the overall type of diet. We could provide further information about this with continued hours of research.
  • Furthermore, we have provided information regarding the regulation of blood glucose levels by the circadian rhythms and how people with misalignments of this rhythm can have altered glycemic levels. We could provide additional information about situations and diseases that change blood glucose levels with further research.