INSULIN, EXERCISE, DIET – WHAT’S THE LINK ???
Insulin derived from Latin – insula means “island”, is a peptide hormone secreted by beta cells of the pancreatic islets, is considered to be the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of glucose from the blood into liver, fat and skeletal muscle cells. When you eat, your blood glucose levels rise, and this makes pancreas to release insulin, so the glucose can be stored as energy for later use. Without this pancreatic function, it makes the person to become either type 1 diabetes or advanced type 2 diabetes, and your blood sugar levels may rise dangerously high, or drop too low. Obesity and sedentary lifestyle are the main predeterminants of poor metabolic and vascular health. Our focus has to be in mainly understanding the mechanisms underlying health improvements by physical activity and the food we consume.
WHAT CAN WE DO?
It’s not that we have to have a well-built gym, or we have to go to the trainers to have us healthy and fit. There are various studies showing that, we can have a proper sensitization of insulin if we do our physical activities in a day to day basis regularly in our home provided with minimal supervision.
Advancing age is the primary risk factor for cardiovascular diseases (CVD) and the leading cause of morbidity and mortality in the developed world. Increased arterial dysfunction, marked by impaired vascular endothelial-dependent dilatation (EDD), is a key antecedent of age-related CVD risk. Impaired EDD is mediated by increased superoxide-related oxidative stress, inflammation, and consequent decreased bioavailability of the vasodilatory molecule nitric oxide (NO).
LINK BETWEEN INSULIN AND NITRIC OXIDE
Insulin resistance increases with age, is an independent predictor of age-related CVD. There is an evident link between insulin action and arterial function. Insulin signals in skeletal muscle, adipose tissue and liver for nutrient storage and maintenance of euglycemia. Insulin also signals in the vascular endothelium to increase production of endothelial NO-synthase and to ultimately promote vasodilatation.
Furthermore, there is a clear link between
»insulin sensitivity and
»vascular endothelial function.
STUDIES OVER THE YEARS ABOUT PHYSICAL INACTIVITY.
1. Seals and Holloszy et al., (1984) *Master athletes have similar insulin sensitivity to young trained adults, physical activity may preserve insulin function with advancing age.
2. Rogers et al., (1990) 10 days of physical inactivity significantly decreased insulin sensitivity in masters athletes.
3. Rinder et al., (2000) Exercise training enhances endothelial function in healthy older adults.
*Master athletes – athletes regularly doing physical exercise or athletic events and above 30 years of age.
In a study by Reidy et al., in 2018, found that physical inactivity-induced insulin resistance may be due to impaired vascular endothelial function. Three hours of sitting has been shown to significantly decrease vascular endothelial function in healthy adults. In contrast, it takes 4 days of bed rest to induce insulin resistance, where there is no effect after 1 day.
Another study by Scott et al., in 2019, proposed a plan Whether home based exercise can mitigate insulin resistance and vascular dysfunctions while eliminating potential barriers of exercise adherence like not able to access to facilities.
He summarised his study by increased eNOS/NOX concomitant with improved endothelium dependant dilatation and insulin sensitivity; the two early markers for CVD and T2DM – i.e., endothelial dysfunction and insulin resistance can be delayed or even prevented, with just virtually monitoring home based exercises.
REGULAR ACTIVITY IS MUST
Individuals who regularly perform exercise (i.e. who are exercise-trained) are characterized by elevated insulin sensitivity compared to untrained individuals. So, it is necessary that to maintain regular exercise, so that insulin sensitivity can be maintained. And the main thing lies in doing physical activity in a regular basis. Another study by, one of the forerunners Heath et al., in 1983, that the high-level insulin sensitivity in individuals who were regular exercisers (45 min/day, 5–7 days/week for at least 6 months) could be lost quickly after sedentary behavior (of only 10 days duration), and then essentially fully restored after performing only one exercise session.
Hereby, the evident point lies not in just doing exercise and leaving in middle, similarly not by just doing erratic exercises, but lies in the fact that all the insulin sensitivity, physical activity, diet, all been intertwingled with one another and these are the early detectors of Cardio Vascular diseases. Keeping that in mind, we have to encourage and motivate the population, not only to just do the physical exercise, instead we have to motivate the persons and the family members to keep an eye on them, provides the benefits and betterment of the individual and society.
1. Cartee GD. Mechanisms for greater insulin-stimulated glucose uptake in normal and insulin-resistant skeletal muscle after acute exercise. Am J Physiol Endocrinol Metab. 2015;309:949-59.
2. Heath GW, Gavin JR 3rd, Hinderliter JM, Hagberg JM, Bloomfield SA & Holloszy JO. Effects of exercise and lack of exercise on glucose tolerance and insulin sensitivity. J Appl Physiol. 1983;55:512–7.
3. Steenberg DE, Jorgensen NB, Birk JB, Sjoberg KA, Kiens B, Richter EA & Wojtaszewski JFP. Exercise training reduces the insulin-sensitizing effect of acute exercise in human skeletal muscle. J Physiol. 2019;597:89–103.
4. Cesar A. Meza. Home exercise reduces cardiometabolic disease risk. 2019;597(24):5745-47.
5. Frye J, Clayton ZS. Physical inactivity-induced insulin resistance: could alterations to the vasculature be to blame?. J Physiol. 2019;597(2):375–6.
Dr. VinothKumar. N