Diaphragmatic breathing reduces postprandial oxidative stress - Martarelli et al. (2011)
Key Points
High blood sugar causes oxidative stress
Diaphragmatic breathing reduces blood sugar, increases insulin, and reduces oxidative stress after eating a meal
The positive effects of diaphragmatic breathing on oxidative stress are likely due to activation of the parasympathetic nervous system
The Breathing Diabetic Summary
This study was motivated by a previous paper that showed that seated meditation lowered the blood sugar of type 2 diabetics (notes coming soon). What the current authors set out to investigate was whether a similar exercise, diaphragmatic breathing (DB), could also lower postprandial blood sugar (i.e., after a meal is eaten). This is important because even nondiabetics experience a moderate spike in blood glucose after a meal. And, more importantly for us, this moderate postprandial spike in blood sugar can cause oxidative stress. This paper wanted to see if using DB to reduce postprandial blood sugar would also reduce the associated oxidative stress.
The participants of this study were asked to consume a 900-calorie breakfast comprised of 80% carbs, 10% fats, and 10% protein. Then, 10 minutes after the meal, one group performed diaphragmatic breathing for 40 minutes while the control group sat quietly and read a magazine. Blood samples were taken before the meal and 1 hour and 2 hours after the meal. They measured blood glucose, insulin, reactive oxygen metabolites (ROMs, which are an indicator of oxidative stress), and biologic antioxidant potential (BAP, which measures antioxidant status). Heart rate also was measured throughout the entire experiment.
The results showed that DB increased insulin and reduced blood glucose, leading to a smaller postprandial blood sugar spike. This is consistent with the Wilson et al. (2013) study, which showed that relaxation breathing reduced blood sugars after an oral glucose tolerance test. They also found that antioxidant status (BAP) was significantly increased in the DB group compared to the controls. Thus, diaphragmatic breathing might be a way to combat oxidative stress associated with high blood sugar. Finally, the heart rate of the DB participants also was significantly lower 60 minutes after the meal.
All of these results can be explained by a shift into a parasympathetic state, which would lower heart rate and increase insulin production. This is consistent with the findings of Wilson et al. (2017). If you’re a type 2 diabetic, these results are immediately applicable and you can begin using DB as a way to increase insulin production. The reduction in oxidative stress (via the increase in antioxidant status) seen here is important to all diabetics, who often experience hyperglycemia and thus suffer from higher levels of oxidative stress and its negative side effects. Let’s start using Principle 1 today to increase insulin, lower blood sugar, and decrease oxidative stress!
Abstract from Paper
Objectives: A number of studies suggest that postprandial hyperglycemia produces oxidative stress, leading to complications associated with diabetes. However, hyperglycemia-induced oxidative stress may affect groups of people other than diabetics, such as smokers and athletes with specific diet plans. Based on previous reports that seated breathing meditation reduces hyperglycemia, the present study was designed to determine the effects of diaphragmatic breathing on postprandial plasma glycemia, insulin, oxidative stress, and antioxidant levels in athletes with normal glucose metabolism.
Design: Data collected before and after consumption of a 900-calorie breakfast composed of 80% carbohydrates, 10% proteins, and 10% lipids were analyzed. Ten (10) minutes after the meal, 8 subjects spent 40 minutes performing diaphragmatic breathing in a quiet place. The other 8 subjects, representing the control group, spent the same time sitting in an equivalent quiet place reading a magazine.
Subjects: Data from 16 amateur male cyclists age 30.12 – 4.9 years ( – SD) were analyzed. Their mean height and weight were 177.81 – 5.3 cm and 71.40 – 5.2 kg, respectively. All subjects underwent a physical examination and were determined to be in good health.
Outcome measures: Blood samples were collected immediately before the meal as well as 1 hour and 2 hours after the meal, and plasma levels of glucose, insulin, reactive oxygen metabolites, and biologic antioxidant potential were determined. Heart rate was also recorded.
Results: Results show that in normal subjects, acute hyperglycemia induces free-radical production while reducing the antioxidant levels ( p < 0.05). Diaphragmatic breathing reduces heart rates ( p < 0.01), increases insulin ( p < 0.05), reduces glycemia ( p < 0.01), and reduces free-radical production as indicated by the higher antioxidants levels ( p < 0.05).
Conclusions: Diaphragmatic breathing, likely through the activation of the parasympathetic nervous system, increases insulin, reduces glycemia, and reduces reactive oxygen species production.
Journal Reference:
Daniele Martarelli, Mario Cocchioni, Stefania Scuri, and Pierluigi Pompei, (2011) Diaphragmatic breathing reduces postprandial oxidative stress, The Journal of Alternative and Complementary Medicine, 17 (7), 623-628, DOI: 10.1089/acm.2010.0666